Molecular Biomarkers for the Treatment of Lung Cancer Personalized Therapy Beyond the EGFR Mutation

91

Leading ArticleMolecular Biomarkers for the Treatmentof Lung Cancer: Personalized TherapyBeyond the EGFR Mutation

Kenichi Suda, MD, PhD^l and Tetsuya Mitsudomi, MD,^Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University,Fukuoka; ^ Division of Thoracic Surgery, Department of Surgery, Kini

92 Kenichi Suda and Tetsuya Mitsudomi

Regarding the treatment of lung cancer, anumber of predictive biomarkers have recentlybeen evaluated to select patients who willbenefit from treatment with specific drugs,and some of these markers have already founduse in the clinic. In particular, oncogenicdriver mutations are now regarded not onlyas key molecules for lung carcinogenesis butalso as distinctly useful molecular biomarkersfor lung cancers with targetable molecules(Figure 1). A well-established example isthe mutation in the gene that encodes theepidermal growth factor receptor (EGFR),discovered in 2004 [1,2].

In this article, we will focus on molecularpredictive biomarkers that appear to beparticularly hopeful, especially those thatindicate potential benefits from treatmentwith EGFR tyrosine kinase inhibitors (TKIs).

Personalized therapy based onmolecular biomarkers in lung cancerAt the beginning of the 21st century,clinicians treated lung cancer as twodiseases, namely NSCLC and SCLC.Treatment strategies, including choice ofdrugs, were usually based on this distinction.However, recent developments in moleculardiagnostic technology and the advent ofmolecularly-targeted drugs are changing thissituation dramatically.

The initial trials of molecular biomarkersin lung cancer were trial-and-error processes.When the first ATP-competitive first-generation EGFR-TKI (gefitinib) wasadministered to patients, no biomarker wasknown that would indicate the effectivenessof this drug. Shortly after, initial observationsidentified East-Asian ethnicity, female sex,never-smoker status, and adenocarcinomahistology as clinical biomarkers for a goodresponse to gefitinib treatment [3].

In 2004, two genetic aberrations of thetarget molecule were proposed as molecularbiomarkers that predict response to gefitinib:.EGF-activating somatic mutations [1,2]and EGFR copy number gain [4]. As thesetwo molecular aberrations often overlap [5],it was difficult to obtain the final conclusionregarding the proper molecular biomarker

until the results of biomarker analyses fromthe IPASS (Iressa Pan-Asian Study) werereported [6]. IPASS was a randomized. PhaseIII study of first-line treatment for never orlight smokers with adenocarcinoma histologyin Asia comparing gefitinib with carboplatin-paclitaxel chemotherapy [7]. In the subset ofpatients whose EGFR status was analyzable,progression-free survival (PFS) was longer inthe gefitinib-treated group of patients withan EGFR mutation regardless of high or lowEGFR copy number, whereas PFS was shorterin the gefitinib-treated group of patientswithout an EGFR mutation and high EGFRcopy number [6].

Molecular biomarkers for EGFR-TKIsin lung adenocarcinomaEGFR mutation as a molecularbiomarker for EGFR-TKIsLung cancers with an EGFR mutation accountfor approximately 40% of adenocarcinomas inEast Asians and approximately 15% of thosein Caucasians. Many in vitro observations andretrospective and prospective studies havereported that lung cancers with an EGFRmutation respond very well to EGFR-TKIs,whereas those without EGFR mutations donot [8]. For chemotherapy-naive patients withlung cancer with EGFR mutations, five PhaseIII trials have demonstrated that the rates ofPFS of patients who were treated with EGFR-TKIs (gefitinib, erlotinib, or afatinib) weresuperior to those of patients who receivedplatinum-doublet chemotherapy [9-13].However, the question of whether EGFR-TKIsprolong overall survival (OS) in lung cancerpatients with EGFR mutations could not beanswered in these trials because of the highcrossover rate between both arms. A historicalcomparison between patients who were treatedbefore and after approval of gefitinib in Japanhas given a strong indication regarding thismatter [14]. OS was significantly longer amongthose who were treated after gefitinib approvalcompared with that in those who were treatedbefore gefitinib approval in patients withan EGFR mutation (median survival time[MST] 27.2 months vs. 13.6 months; p

Molecular Biomarkers for the Treatment of Lung Cancer 93

Figure 1 . Sub-classification of lung cancer patients for biomarker-based molecular targeted therapy.Current and future sub-classification of patients with lung cancer based on driver oncogenes asmolecular biomarkers. A: The frequencies of these oncogenic driver mutations are different betweenpatients with differing pathological histology. Infrequent mutations that cause adenocarcinoma includethose caused by HER2. BRAF. ROS. and MET. The frequencies and suitable molecular target drugsfor each driver oncogene are summarized in Tables 1 and 2. B: There is heterogeneity within lungadenocarcinoma patients with an fCF/? mutation and molecular biomarkers beyond fCFR mutation.Improvement of response might be obtained if the patients with inherent resistance or those withlow efficacy to gefitinib or eriotinib are treated with other EGFR-TKIs or with combination therapy.Note that these molecular mechanisms that confer inherent resistance or low efficacy to gefitinib oreriotinib are not necessarily mutually exclusive. Next-generation ECFR-TKIs include irreversible ECFR-TKIs and/or T790M-specific ECFR-TKIs.

Histologicalclassification

Molecular classification(biomarkers and candidates)

ECFRInfrequent

ALK I mutations

AdenocarcinomaMMMl

Ill 111 KRAS r i i n i n n i ~ r unknown

mH HI H DDR2 ffl ffl eCFR VIII

Squamous cell fffcarcinoma w j^i w w' f-^/.f~.^ ,, ,

ffl ffl U tu FCFR7 Unknown

Lung cancer patients Small cell carcinoma

Low efficacy togefitinib/erlotinib

Low IKB

T790MHI 111 lU 111 HI UJ Minor clone

Lung cancer patientswith EQFR mutation

Higher response togefitinib/erlotinib

M/C UIIUUIIlllllllllIllll Unknown

Candidates for future treatment

Low BIM ECFR-TKIs + BH3 mimetics

ECFR-TKIs + IKK inhibitor

Next-generation ECFR-TKIs

C719X or otherrare mutation Next-generation ECFR-TKIs

Inherent resistance to gefitinib/erlotinib

Exon 20 &insertion ID T790M Next-generation ECFR-TKIs

High HCF expression ECFR-TKIs + MET inhibitor

PTEN" loss ECFR-TKIs + PBK/AKT inhibitorALK : anaplastic lymphoma kinase; BH3: BCL-2 homology domain 3; BIM: BCL-2-like-i 1: D0R2: discoidin domain receptor tyrosinekinase-2; ECFR: epidermal growth factor receptor: FGFRl: fibroblast growth factor receptor-i; HER2: human ECFR-2: IKB: inhibitor of KB;IKK: IKB kinase; MET: hepatocyte growth factor receptor; PI3K: phosphoinositide-3-kinase; PTEN: phosphatase and tensin homolog;TKI: tyrosine kinase inhibitor.


survival was observed in patients withoutEGFR mutations (MST 13.2 months vs. 10.4months; p=0.13). Similar results have alsobeen obtained in patients with lung cancerin analyses that were restricted to those withpost-surgical recurrences [15].

Biomarkers and candidates thatpredict resistance to ECFR-TKIsUnfortunately, even in patients with EGFR-mutant lung cancer, clinicians have noticedthat some of these patients have poor responsesto treatment with gefitinib or erlotinib. Initialreports attributed the difference in responseto the type of EGFR mutation. Patients withthe two most common mutations, exon 19deletion and L858R point mutation, respondedvery well to treatment with an EGFR-TKI;those with a G719X point mutation respondedless well, whereas the presence of an exon20 insertion mutation indicated intrinsicresistance to treatment [8]. In addition, thepretreatment T790M gatekeeper mutation(which is present in approximately 0.5% ofpatients with lung cancer with an activatingEGFR mutation) [16] and loss of thephosphatase and tensin homolog (PTEN)tumor suppressor gene [17] have also beenreported to cause inherent resistance to theseEGFR-TKIs (Figure 1). Furthermore, ina recent analysis using clinical specimensfrom EGFR-mutam lung cancer patientswho showed inherent resistance, Yano et al.observed that high levels of expression ofhepatocyte growth factor (HGF; a ligand ofthe HGF receptor [MET] proto-oncogene)were detected in 29% of tumors and MET gtncamplification in 4%, suggesting that thesemolecules might be biomarkers for intrinsicresistance to EGFR-TKIs in patients with lungcanccT with EGFR mutations [18].

Biomarkers and condidates thotpredict low responses to EGFR-TKIsAmong patients who respond to gefitinibor erlotinib, some patients have a shorterlength of PFS. To explain this phenomenon,Maheswaran et al. analyzed pretreatmenttumor specimens for very minor clones ofthe T790M EGFR mutation using a high-

sensitivity method [19]. Interestingly, veryminor clones of the T790M mutation weredetected in 38% of patients with lung cancerwith an EGFR mutation, and correlated withreduced PFS following treatment with EGFR-TKIs compared with patients who did not haveminor clones of the T790M mutation. However,this is still controversial because Fujita et al.have observed the opposite result [20].

Molecular biomarkers other than EGFRhave also been found to influence the responseto EGFR-TKI treatment. We observed thatEGFR-TKI-treated patients with high levelsof expression of PTEN showed favorablesurvival compared with those who had lowerlevels of PTEN expression [21]. In addition,Bivona et al. identified that FAS and nuclearfactor-KB (NF-KB) signaling mediated thesuppression of cell death induced by EGFR-TKIs [22]. Following this observation, theinvestigators analyzed the levels of expressionof NF-KB inhibitor-a (NFKBIA; also knownas IKB) in patients with lung cancer withEGFR mutations and found that low levels ofNFKBIA expression (which induces a highactivation state of NF-KB) was predictive ofworse PFS, whereas NFKBIA expression didnot predict PFS in those who were treatedwith chemotherapy. Recently, Fabor et al. andNg et al. have demonstrated that low levels ofexpression of BCL-2-like-ll-EL (BIM-EL;one of three isoforms of the BIM protein), andan intronic deletion polymorphism of BIMthat provides decreased expression of BIM-EL, predict worse response to EGFR-TKItreatment in patients with EGFR-mutatedlung cancers [23,24].

In the future, these molecular biomarkersthat predict inherent resistance or low efficacyto EGFR-TKIs in patients with lung cancerwith an EGFR mutation could be importantfor further sub-classification of patientswith EGFR-mmam lung cancer for furtherbiomarker-directed treatment.

Biomarkers post-acquisitionof resistance to first-generation EGFR-TKIsDespite initial (potentially) dramaticresponses, almost all patients with lung


cancer with an EGFR mutation eventuallydevelop acquired resistance to gefitinib orerlotinib. Molecular mechanisms underlyingthis acquired resistance have been extensivelyanalyzed. These mechanisms can be usefulbiomarkers for selecting the appropriatetreatment for these patients after acquisitionof resistance to first-generation EGFR-TKIs.

Acquisition of the T790M gatekeepermutation of the EGPR is the most frequentlyacquired resistance mechanism [25,26]; therate of development of this mutation has beenfound to be up to 68% using a high-sensitivitydetection method [27]. To overcome resistancecaused by the T790M mutation, second-generation EGER-TKIs that bind irreversiblyto EGFR or third-generation EGFR-TKIsthat are designed to inhibit mutant EGFR,including T790M but not wild-type EGFR,are now under development. These novelEGFR-TKIs have been found to be highlyeffective in preclinical models [28,29];however, afatinib (a second-generationTKI) failed to improve OS compared withplacebo in patients who experienced diseaseprogression following treatment with gefitinibor erlotinib in a recent trial [30].

The second candidate of targetableacquired resistance is MET activationby gene amplification [31,32] or by highexpression of the ligand (HGF) [33]. Invitro models of acquired resistance causedby MET activation are highly responsive tocombination therapy with an EGFR-TKI anda MET-TKI [31,33,34].

There are several other candidates ofacquired resistance mechanisms to EGFR-TKIs in patients with lung cancer with EGFRmutation, such as PTEN downregulation,amplification of v-crk sarcoma virus CTIOoncogene homolog (avian)-like (CRKL),activation of NF-KB signaling; activationof the AXL receptor tyrosine kinase(AXL), HER2 amplification, epithelial-to-mesenchymal transition, or conversion toSCLC [35-37]. These molecular mechanismsof acquired resistance might be goodmolecular biomarkers for selecting treatmentto overcome resistance to first-generationEGFR-TKIs in the near future.

/ILK^translocation and ALK-TKIsTranslocation and activation of the anaplasticlymphoma kinase (ALK) proto-oncogenein lung adenocarcinoma was first observedin 2007 [38,39]. Using transgenic mousemodels, several ALK fusion genes (such asechinoderm microtubule-associated proteinlike-4 [EML4]-ALK, kinesin family member-5B [KIF5B]-ALK, or kinesin light chain-1[KLC1]-ALK) that have been identified inpatients with adenocarcinoma have beenshown to be oncogenic and highly sensitive toALK-TKIs [38,40,41]. Although lung cancerswith ALK translocations account for only 5%of adenocarcinomas, development of the ALKinhibitor crizotinib was focused on patientswith ALK fusion genes by applying lessonsthat were learned from EGFR-TKIs [42]; thisresulted in rapid approval by the US Foodand Drug Administration - only 4 years later- after the discovery of ALK fusion genes inlung cancers. This is a typical success story ofdrug development based on patient selectionusing a molecular biomarker.

As with EGFR-TKIs, a retrospective studyhas also been performed to demonstrate theability of crizotinib to prolong OS in patientswith lung cancer with an ALK translocation.Shaw et al. compared 30 ^LA^-translocation-positive patients who were given crizotinib inthe second- or third-line setting with 23 ALK-translocation-positive controls who were givenother second-line therapy, and identifiedsignificantly longer OS in the crizotinib-treated group [43]. Currently, a Phase IIItrial comparing crizotinib with platinum-doublet chemotherapy in the first-line settingin patients with lung cancer with an ALKtranslocation is underway (www.clinicaltrials.gov identifier: NCT01154140). In addition,other ALK inhibitors are now undergoingclinical development [44].

Oncogenic driver mutationsin adenocarcinoma: futurecandidate biomarkersMutations in other driver oncogenes (suchas human EGFR-2 [HER2] [45,46], BRAF[47], and mitogen-activated protein kinasekinase 1 [MEKl] [48]), other fusion genes


Table 1. Oncogenic driver mutations as molecular biomarkers in lung adenocarcinomas.Biomarkers

ECFR mutation

KRA5 mutation

AL/ftranslocaticn

HERZ mutation

ROSI translocation

R7" translocation

MET amplification

6R/IF mutation

MEK1 mutation

Frequencies

40% in Asians;15% in Caucasians

15% in Asians:30% in Caucasians

5%

2%

3%

1-2%

2%

3-5%

1%

Effective drugs or candidates

Reversible ECFR-TKIs: gefitinib and erlotinib

Irreversible ECFR-TKIs: afatinib and dacomitinib

T790M-specific EGFR-TKIs: CO-1686 and WZ4002

Inhibition of molecular targets that cause synthetic lethality

Selumetinib combined chemotherapy

Sorafenib

Crizotinib

Other ALK inhibitors

Trastuzumab combined chemotherapy

Irreversible pan-HER-TKIs: afatinib and dacomitinib

CrizotinibVandetanib, sorafenib, sunitinib

Crizotinib

Sorafenib

Selumetinib

References

[9-12][13][29][64][65][66][42][44][57,58][56,59,60][61,62][51,63][54][66][48]

ALK: anaplastic lymphoma kinase: ECFR: epidermal growth factor receptor: HER2: human ECFR-2: MEK-1 : mitogen-actiuated proteini


Table 2. Oncogenic driver mutations as molecuiarBiomarkers

eCff iv i l l mutation

FCFR1 amplification

DDRZ mutation

MyCampiiflcation

Frequencies

5% in SqCLC

22% in SqCLC

3.8% in SqCLC

3-7% in SCLC

biomarkers in lungCandidate drugs

HKI-272

PD173074

Dasatinib

SqCLC or SCLC.References

[67][68][69]

Aurora kinase inhibitors [70]DDR2: discoidin domain receptor tyrosine kinase-2; ECFR: epidermal growth factor receptor,SqCLC; squamous cell lung carcinoma.

FCFRl : fibroblast growth factor receptor-l:

molecules for AT/i^S-mutation-driven lungcancers are currently underway [64]. Inaddition, a recent clinical trial suggestedthe efficacy of a combination of selumetinib(a MEKl/2 inhibitor) plus docetaxel [65], orsorafenib monotherapy [66], in patients withlung cancer with a KRAS mutation.

Oncogenic driver mutations insquamous cell carcinomas and SCLC:future candidate biomarkersFor the seeond and the third mostcommon types of lung cancer (squamouscell carcinoma and SCLC, respectively),no targeted therapies to inhibit driveroncoproteins have been developed.However, several studies have suggestedthe existence of driver mutations in thesecancers (Figure 1 and Table 2). The EGFRvariant III (vIII) mutation that lacks exon2-7 of its extracellular domain has beendetected in 5% of lung squamous cellcarcinomas [67]. EGFR vlll-driven murinetumors have been shown to be sensitive toHKI-272, an irreversible BGFR-TKI [67].Recently, two other driver mutations - focalamplification of the fibroblast growth factorreceptor-l (FGFRl) gene, and a mutationin the gene that encodes discoidin domainreceptor tyrosine kinase-2 (DDR2) - havebeen reported in 22% and 3.8% of lungsquamous cell carcinoma cases, respectively.Lung cancer cell lines harboring FGFRlamplifications (such as H1581 and H520)were sensitive to a non-isoform-specificFGFR inhibitor PD173074 [68]. Lungcancer cell lines harboring DDR2 mutations(H2286 and HCC366) were also sensitive tothe multi-target kinase inhibitor dasatinib.

In addition, a squamous cell lung cancerpatient who responded to combinationtherapy with dasatinib and erlotinib wasreported to harbor a DDR2 mutationbut not an EGFR mutation [69]. Clinicaltrials for Z)Di?2-mutated lung cancers arecurrently underway.

In SCLC, MYC amplification reportedlyoccurs in 3-7% of tumors. A recent studyidentified that Aurora kinase inhibitors(which inhibit kinase activity of Aurorakinase B) are effective in SCLC cell linesbearing MYC amplification [70].

These driver mutations in lung squamouscell carcinoma or in SCLC might be used asbiomarkers in the near future.

Molecular biomarkers for drugs thatdo not target driver mutationsConventional cytotoxic chemotherapies arestill the "gold standard" for the treatment oflung cancers. For cytotoxic drugs, althoughno molecular biomarkers have been acceptedby the scientific community-at-large, theusefulness of several molecular biomarkershave been suggested from in vitro data orfrom exploratory analyses, and some ofthem are being evaluated in clinical trials.Because many cytotoxic drugs kill cancercells by inducing DNA damage, the levelsof expression of several DNA repair genes,some of which have also been reported asprognostic markers, are candidate biomarkers.For example, in the IALT-bio (InternationalAdjuvant Lung Trial-bio) study, patientswith excision repair cross-complementingrodent repair deficiency, complementationgroup-1 (ERCC-l)-positive tumors byimmunohistochemical analysis survived


longer (i.e. ERCC-1 acted as a prognosticmarker), whereas platinum-based therapysignificantly prolonged survival amongpatients with ERCC-1-negative tumors but notwith -positive tumors (and thus it acted as apredictive biomarker for this therapy) [71].

Expression of target genes has alsobeen reported as a biomarker for cytotoxicchemotherapy. Thymidylate synthase (TS) isthe main target of a multi-targeted antifolate,pemetrexed. In a preplanned subset analysisof a Phase III trial, cisplatin plus pemetrexedresulted in longer OS in patients with non-squamous histology but shorter OS in thosewith squamous cell carcinoma comparedwith cisplatin plus gemcitabine (cisplatinplus gemcitabine showed similar OS in bothhistology groups) [72]. Lower TS expressionin non-squamous histology carcinomacompared with that in squamous cellcarcinoma is suggested to form the molecularbasis of this result [73]. In vitro analysis,which found expression of TS to be predictiveof pemetrexed chemosensitivity, furthersupports this hypothesis [74]. Other candidatetarget genes as biomarkers are summarized inTable 3 [75-78].

The addition of a third agent, amonoclonal antibody targeting BGFR(cetuximab) or vascular endothelialgrowth factor (bevacizumab), to platinumdoublet chemotherapy has been reportedto be effective in some patients. Predictivebiomarkers have also been extensivelyexamined for these antibody drugs. Inbiomarker analyses using data from thePhase III FLEX (First-Line Erbituxin Lung Cancer) study, high levels ofexpression of EGFR (as determined byimmunohistochemistry) [79], but not EGERmutation, EGFR copy number, KRASmutation, nor PTEN expression [80], wasreported as a positive predictive biomarkerfor response to treatment with cetuximab.For bevacizumab, no significant predictivebiomarker has been discovered; high baselineplasma VEGF levels were reported tocorrelate with higher response to treatmentincluding this antibody, but did not predict asurvival benefit [78].

Recent and ongoing clinical trialsutilizing molecular biomarkersPlatinum-doublet adjuvant chemotherapy,the current standard of care for pathologicalstage II-III NSCLC patients after "curative"resection, improves the 5-year survival rateby only 5.4% compared with surgery alone[81]. Because pulmonary resection providesabundant tumor tissues for molecularanalyses, several molecular-biomarker-based clinical trials in the adjuvant settinghave been performed or are ongoing (forfurther information in this area, see thecurrent authors' recent review [82]). Someof these trials have included EGFR statusas a molecular biomarker for the selectionof adjuvant chemotherapy. Although theprematurely terminated BR.19 trial couldnot show the efficacy of adjuvant gefitinibtherapy compared with placebo even in asubset of patients with EGER mutations[83], one retrospective study found thatadjuvant EGFR-TKI was associated with alower risk of recurrence [84]. To confirm therole of adjuvant EGFR-TKI prospectively inNSCLC patients with an EGER mutation.Phase III trials that compare gefitinib withcisplatin plus vinorelbine are now ongoing.In addition, to confirm the efficacy ofbiomarker-tailored adjuvant therapy, severalPhase III trials that compare customizedtreatment with standard treatment are nowongoing. A specific example of such a trial isthe TASTE (Tailored Post-Surgical Therapyin Early-Stage NSCLC) study, in whichpatients are assigned to three groups in thecustomized arm: eriotinib for those with anEGER mutation, cisplatin plus pemetrexedfor those without an EGER mutation and lowlevels of ERCC-1, and none for those withoutan EGER mutation and high levels of ERCC-1, whereas all of the patients in the standardarm receive cisplatin plus pemetrexed.

A biopsy-mandated, biomarker-based,adaptive-randomization prospective studyhas also been performed for unresectable,heavily-treated patients with NSCLC (theBATTLE [Biomarker-Integrated Approachesof Targeted Therapy for Lung CancerElimination] trial) [66]. Following an initial


Table 3. Candidate biomarkers for chemo-therapeutic drugs that do not target drivermutations [71-77].ERCC-1High expression

BRCA-1Low expression

MSH-2Low expression

RRM-1High expression

TSHigh expressionLow expression

Betatubuiin iliLow expression

Resistance to platinum-based therapy

Sensitive to cisplatinResistance to paclitaxeland docetaxel

Resistance to cisplatin

Resistance to gemcitabine

Resistance to pemetrexedSensitive to uracil-tegafur (UFT)

Sensitive to vinorelbine-based therapy

BRCA-l :breast cancer-1; ERCC-1 : excision repair cross-complementation group-1: M5H-2: MutS homologue-2: RRM-1 :ribonucleotide reductase messenger-1; TS: thymidylate symhasa

equal randomization period (97 patients),158 patients were adaptively randomizedto erlotinib, vandetanib, erlotinib plusbexarotene, or sorafenib based on 11 relevantmolecular biomarkers: mutational status ofEGFR, KRAS, and BRAF; fluorescence insitu hybridization (FISH) analysis for EGFRand CCNDl; and immunohistochemicalanalysis for VEGF, VEGFR-2, cyclin Dl,retinoid X receptor-a (RXR-a), RXR-, andRXR-y. Overall results of the BATTLE trialinclude a 46% 8-week disease control rate,suggesting the feasibility of a new paradigmfor a molecular-biomarker-based clinical trial.

Future directions andconcluding remarksAs described above, lung cancerpatients with an EGFR mutation orALK translocation benefit greatly fromindividualized molecularly targeted therapy.In addition, biomarkers are also useful forrapid drug development and successfulclinical trials. Establishment of detectionmethods and the development of molecularlytargeted therapy to other driver mutationsis, therefore, the next step in biomarkerapplication. However, it is also true that a

subgroup defined by a single driver mutationis not uniform, as shown by the heterogeneityof lung cancers with EGFR mutations(Figure 1). In addition, it is unclear whethermolecular biomarkers, usually quantitativebiomarkers, are useful for determiningtreatment with cytotoxic chemotherapeuticdrugs or antibody drugs. To ensure the mostappropriate treatment for all patients withlung cancer, new biomarker exploration aswell as method standardization and knownbiomarker evaluation by investigators,and efforts to obtain tumor specimensfor biomarker analyses by surgeons andphysicians, are needed.

Disclosures: Or. Suda has no relevant financial interests to disclose.Or. Mitsudomi has declared the following financial relationships:speaker's fees from AstraZeneca, Boehringer-lngelheim. Chugai,and Taiho: research support grants from AstraZeneca, Boehringer-lngelheim, Eli Lilly, Pfizer, and Taiho; and consultation fees fromAstraZeneca, Boehringer-lngelheim, Chugai, Clovis, Kyowa HakkoKirin, Novartis, Pfizer, Roche, and Synta.

Address for correspondence: Kenichi Suda, Department ofSurgery and Science, Graduate School of Medical Sciences, KyushuUniversity, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8S82,Japan.Email: ascarisisisrg2.med.kyushu-u.ac.jp

References1. Lynch TJ, Bell DW, Sordella R et al. Activating mutations in the

epidermal growth factor receptor underlying responsivenessof non-small-cell lung cancer to gefitinib. N Engl] Med2004:350:2129-39.

2. Paez JG, Janne PA, Lee JC et al. ECFR mutations in lung cancer:correlation with clinical response to gefitinib therapy. Science2004:304:1497-SOO.

3. Miller VA, Kris MG, Shah N et al. Bronchioloalveolar pathologicsubtype and smoking history predict sensitivity to gefitinibin advanced non-small-cell lung cancer. ] Clin Oncol2004:22:1103-9.

4. Cappuzzo F, Hirsch FR, Rossi E et al. Epidermal growth factorreceptor gene and protein and gefitinib sensitivity in non-small-cell lung cancer.; Now Concer/nst 200S:97:543-5S.

5. Yatabe Y, Takahashi T, Mitsudomi T. Epidermal growth factorreceptor gene amplification is acquired in association withtumor progression of f CW-mutated lung cancer. Cancer Res2008:68:2106-11.

6. Fukuoka M, Wu Yl, Thongprasert S et al. Biomarker analysesand final overall survival results from a Phase III, randomized,open-label, first-line study of gefitinib versus carboplatin/paclitaxel in clinically selected patients with advancednon-small-cell lung cancer in Asia (IPASS).) O/n Oncol2011:29:2866-74.

7. Mok TS, Wu YL Thongprasert S et al. Gefitinib or carboplatin-paclitaxel in pulmonary adenocarcinoma. N EnglJ Med2009:361:947-57.

8. Mitsudomi T, Yatabe Y. Mutations of the epidermal growthfactor receptor gene and related genes as determinants ofepidermal growth factor receptor tyrosine kinase inhibitorssensitivity in lung cancer. Cancer Sei 2007:98:1817-24.

9. Mitsudomi T, Morita S, Yatabe Y et al. Gefitinib versus cisplatinplus docetaxel in patients with non-small-cell lung cancerharbouring mutations of the epidermal growth factor receptor(WJTOGB405): an open label, randomised Phase 3 trial. LancetOnco/2010:11:121-8.

10. Maemondo M, Inoue A, Kobayashi K et al. Gefitinib orchemotherapy for non-small-cell lung cancer with mutatedEGFR. N EngI] Med 2010:362:2380-8.


11. Rosell R, Carcereny E, Gervais R et al. Erlotinib versus standardchemotherapy as first-line treatrtient for European patientswith advanced ECFR mutation-positive non-small-cell lungcancer (EURTAC): a multicentre. open-label, randomisedPhase 3 trial. Lancet Oncol 2012:13:239-46.

12. Zhou C, Wu YL, Chen C et al. Eflotinib versus chemotherapyas first-line treatment for patients with advanced EGFRmutation-positive non-small-cell lung cancer (OPTIMALCTONC-0802): a multicentre. open-label, randomised.Phase 3 study. Lancet Onco/2011:12:735-42.

13. Yang JC-H, Schler MH, Yamamoto N et al. LUX-Lung 3:a randomized, open-label. Phase III study of afatinib versuspemetrexed and cisplatin as first-line treatment for patientswith advanced adenocarcinoma of the lung harboring ECFR-activating mutations. ) Gin Oncal 2012;30(Suppl.): AbstrLBA7500.

14. Takano T, f ukui T, Ohe Y et al. ECFR mutations predictsurvival benefit from gefitinib in patients with advanced lungadenocarcinoma: a historical comparison of patients treatedbefore and after gefitinib approval in Japan. I Clin Oncal2008,26:5589-95.

15. Suda K, Ito S, Mizuuchi H et al. ECFR tyrosine kinase inhibitorsprolong overall survival in CfR mutated non-small-cell lungcancer patients with postsurgical recurrence. J Cancer ResUpdotes 2012:1:102-7.

16. Toyooka S, Kiura K, Mitsudomi T. ECFR mutation and responseof lung cancer to gefitinib. N EngI] Med 2005:352:2136:author reply.

17. Sos ML, Koker M, Weir 8A et al. PTEN loss contributes toerlotinib resistance in f CFR-mutant lung cancer by activationof Akt and ECFR. Cancer Res 2009:69:3256-61.

18. Yano 5, Yamada T Takeuchi 5 et al. Hepatocyte growth factorexpression in ECFR mutant lung cancer with intrinsic andacquired resistance to tyrosine kinase inhibitors in a Japanesecohort. I Thorac Oncal 2011:6:2011 -7.

19. Maheswaran 5, Sequist LV, Nagrath S et al. Detection ofmutations in ECFR in circulating lung-cancer cells. N EngI] Med2008:359:366-77.

20. Fujita Y, Suda K, Kimura H et al. Highly sensitive detection ofECFR T790M mutation using colony hybridization predictsfavorable prognosis of patients with lung cancer harboringactivating ECFR mutation.) Tharac Onco/2012:7:1640-4.

21. Endoh H, Yatabe Y, Kosaka T et al. PTEN and PIK3CA expressionis associated with prolonged survival after gefitinib treatmentin fCFR-mutated lung cancer patients.) Tharac Oncal2006:1:629-34.

22. Bivona TC, HIeronymus H, Parker J et al. FA5 and NF-kappaBsignalling modulate dependence of lung cancers on mutantECFR. Noture 2011:471:523-6.

23. Faber AC, Corcoran RB, Ebi H et al. 8IM expression intreatment-naive cancers predicts responsiveness to kinaseinhibitors. Cancer Discov 2011:1:352-65.

24. Ng KP, Hillmer AM, Chuah CT et al. A common 8IM deletionpolymorphism mediates intrinsic resistance and inferiorresponses to tyrosine kinase inhibitors in cancer. Not Med2012:18:521-8.

25. Kobayashi S, Boggon TJ, Dayaram T et al. ECFR mutationand resistance of non-small-cell lung cancer to gefitinib.NEng/J Med 2005:352:786-92.

26. Pao W, Miller VA, Politi KA et al. Acquired resistance of lungadenocarcinomas to gefitinib or erlotinib is associated witha second mutation in the ECFR kinase domain. PLoS Med2005:2:e73.

27. Arcila ME, Oxnard CR, Nafa K et al. Rebiopsy of lung cancerpatients with acquired resistance to ECFR inhibitors andenhanced detection of the T790M mutation using a lockednucleic acid-based assay. Clin Cancer Res 2011:17:1169-80.

28. Kwak EL Sordella R, 8ell DW et al. Irreversible inhibitors of theECF receptor may circumvent acquired resistance to gefitinib.Prac Nati Acad Sei USA 2005:102:7665-70.

29. Zhou W, Ercan D, Chen L et al. Novel mutant-selectiveECFR kinase inhibitors against EGFR T790M. Nature2009:462:1070-4.

30. Miller VA, Hirsh V, Cadranel J et al. Afatinib versus placebofor patients with advanced, metastatic non-small-cell lungcancer after failure of erlotinib, gefitinib, or both, and oneor two lines of chemotherapy (LUX-Lung 1): a Phase 2b/3randomised trial. Lancet Oncal 2012:13:528-38.

31. Engelman JA, Zejnullahu K, Mitsudomi T et al. METamplification leads to gefitinib resistance in lung cancer byactivating ER8B3 signaling. Science 2007:316:1039-43.

32. Bean J, 8rennan C, Shih JY et al. MET amplification occurs withor without T790M mutations in ECFR mutant lung tumorswith acquired resistance to gefitinib or erlotinib. Prac NatiAcad Sei USA 2007:104:20932-7.

33. Yano S, Wang W, Li Q et al. Hepatocyte growth factor inducesgefitinib resistance of lung adenocarcinoma with epidermalgrowth factor receptor-activating mutations. Concer Res2008:68:9479-87.

34. Suda K, Murakami I, Katayama T et al. Reciprocal andcomplementary role of MET amplification and ECFR T790Mmutation in acquired resistance to kinase inhibitors in lungcancer. Gin Cancer Res 2010:16:5489-98.

35. Sequist LV, Waltman BA, Dias-Santagata 0 et al. Genotypic andhistological evolution of lung cancers acquiring resistance toEGFR inhibitors. Sei Transi Med2011:3:75ra26.

36. Suda K, Mizuuchi H, Maehara Y et al. Acquired resistancemechanisms to tyrosine kinase inhibitors in lung cancer withactivating epidermal growth factor receptor mutation-diversity,ductility, and destiny. Cancer Metastasis Rev 2012:31:807-l 4.

37. Takezawa K, Pirazzoli V, Arcila ME et al. HER2 amplification: apotential mechanism of acquired resistance to EGFR inhibitionin ECFR-mutant lung cancers that lack the second-siteECFRT790M mutation. Concer 0/scov 2012:2:922-33.

38. 5oda M, Choi YL Enomoto M et al. Identification of thetransforming EMI.4-/)i.ff fusion gene in non-small-cell lungcancer. Noture 2007:448:561-6.

39. Rikova K, Cuo A, Zeng 0 et al. Global survey of phospho-tyrosine signaling identifies oncogenic kinases in lung cancer.Ce//2007:131:1190-203.

40. Takeuchi K, Choi YL Togashi Y et al. KIFSB-ALK, a novel fusiononcokinase identified by an immunohistochemistry-baseddiagnostic system for /)L/(-positive lung cancer. Gin Cancer Res2009:15:3143-9.

41. Togashi Y, Soda M, Sakata 5 et al. KLChALK: a novel fusionin lung cancer identified using a formalin-fixed paraffin-embedded tissue only. PloS One 2012:7:e31323.

42. Kwak EL Bang YJ, Camidge DR et al. Anaplastic lymphomakinase inhibition in non-small-cell lung cancer. N EnglJ Med2011:363:1693-703.

43. Shaw AT, Yeap BY, Solomon BJ et al. Effect of crizotinib onoverall survival in patients with advanced non-small-cell lungcancer harbouring ALK gene rearrangement: a retrospectiveanalysis. Lancet Oncal 2011:12:1004-12.

44. Casaluce F, Sgambato A, Maione P et al. ALK inhibitors: a newtargeted therapy in the treatment of advanced NSCLC.7bfget Onco/2013:8:55-67.

45. Stephens P, Hunter C Bignell G et al. Lung cancer: intragenicERBBZ kinase mutations in tumours. Nature 2004:431:525-6.

46. Shigematsu H, Takahashi T, Nomura M et al. Somaticmutations of the HERZ kinase domain in lungadenocarcinomas. Cancer Res 2005:65:1642-6.

47. Paik PK, Arcila ME, Fara M et al. Clinical characteristicsof patients with lung adenocarcinomas harboring BRAFmutations. ) Clin Oncal 2011:29:2046-51.

48. Marks JL Cong Y, Chtale D et al. Novel MEKl mutationidentified by mutational analysis of epidermal growth factorreceptor signaling pathway genes in lung adenocarcinoma.Concer- Res 2008:68:5524-8.

49. Ju Y5, Lee WC, Shin JY et al. A transforming KIFSB andRET gene fusion in lung adenocarcinoma revealed fromwhole-genome and transcriptome sequencing. Genome Res2012:22:436-45.

50. Takeuchi K, Soda M, Togashi Y et al. RET, ROSI and ALKfusions in lung cancer. Not Med 2012:18:378-81.

51. Lipson D, Capelletti M, Yelensky R et al. Identification of newALK ana /?ET gene fusions from colorectal and lung cancerbiopsies. Not Med 2012:18:382-4.

52. Kohno T, Ichikawa H, Totoki Y et al. MFSS-RETfusions in lungadenocarcinoma. Nat Med 2012:18:375-7.

53. Onozato R, Kosaka T. Kuwano H et al. Activation of METby gene amplification or by splice mutations deleting theJuxtamembrane domain in primary resected lung cancers,y r/ioroc Onco/2009:4:5-11.

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