Molecular and Histopathologic Prognostic Factors in Rectal Cancer

Monirath Hav, MD, Ph.D. fellow (VLIR project)

Pathology Department

Ghent University Hospital

Promoters: Prof. Dr. Piet Pattyn & Prof. Dr. Claude Cuvelier

Prognostic value of MSI : a comparative study

• Cambodians : 37 cases

• Belgians : 39 cases

• Criteria : revised Bethesda guidelines

• IHC for MMR proteins MSI testing?

• MSI status prognosis

Literature review

• MSI occurs in 10-20% of colorectal cancer

• MSI in rectal cancer is a rare event (2%), but if present, is strongly associated with HNPCC

M. Nilbert et al. Eur. J. of Cancer, issue 6, June 1999, Pages 942-945

What has been known about MSI in Belgian population ?

• MSI in colon CA : 12.4%

• MSI in rectal CA : 1.11%

• MSI has no prognostic value in colon cancer

Vanessa Deschoolmeester et al.

European Journal of Cancer 44 (2008) 2288-229

Hypothesis & questions

• Is there a difference in MSI status between the 2 populations?

• If yes, is there a difference in prognostic value of MSI?

• Based on your experience, how good is the correlation between IHC for MMR proteins & MSI testing?

MDM2 amplification negatively predicts response to neoadjuvant therapy in rectal cancer

Current study

• 71 cases 59 with neoadjuvant T.

• IHC: MDM2 & p53 on biopsies & resections

• p53 mutation analysis

• MDM2 Fluorescent In Situ Hybridization (FISH) : on biopsies

• Correlation with T downstaging and prognosis

The Two Major Apoptotic Pathways

Ashkenazi A. Nat Rev Can 2002;2:420–430.

Caspase 3, 6, 7

Apoptosis

Pro-apoptotic ligand

FADD

FLIP

DR5

DR4

Cell-extrinsicpathway

Procaspase 8, 10

p53p53

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

SMAC/DIABLO

ChemotherapyRadiotherapy

DNA damage

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

IAP

Cell-intrinsicpathway

BCL2, BCLXL,

MCL1

mdm2

mdm2

mdm2mdm2

mdm2

Hypothesis • Presence of MDM2 overexpression in rectal cancer !

• MDM2 overexpression - wild-type p53

• MDM2 overexpression - absence of p53

• MDM2 overexpression / amplification

no p53-dependent apoptosis

no downstaging (no response to neoadjuvant)

MDM2 Amplification in endoscopic biopsy

Conventional chemoradiation T. does not work Need for combination with targeted T. (i.e Nutlins & RITA inhibit mdm2-p53 binding )

Peri-tumoral inflammation :

favorable prognostic factor in rectal cancer

• Inflammation as favourable prognostic factor in 5 studies:

– EORTC study.– Leuven study.– Cetuximab study.– Shia et al. Am J Surg Pathol 2004; 28: 215.– Knutsen et al. Oncol Rep 2006.

• No prognostic value:

– Perez et al. J Gastrointest Surg 2007; 11: 1534.

• 5 positive studies: time from end neoadjuvant treatment to surgery always < 6 weeks, while at least 8 weeks in Perez et al.

Annelies Debucquoy et al. Eur. Journ. of Cancer 44 (2008) 791-797

The current study

• 71 patients (2005-2008 : stage I – III ; mean FU time = 18Ms ) • 59 cases with neoadjuvant • Interval neoadj-surgery : +/- 6 weeks• Peri-tumoral inflammation (PTI): cut-off 25%• T Downstaging (38 cases) DFS & N+• PTI tumor downstaging • PTI DFS • Tumour deposits DFS

Response to treatment causes tumor damage and necrosis, which increases inflammatory reaction and elicits a specific immune response:

– Peritumoral inflammation correlates with T downstaging, which is a measure of tumor response to treatment.

– Postoperative chemo tends to be effective when inflammation is present.

– Prognostic value of inflammation increases with less time between end of neoadjuvant treatment and surgery (<6 weeks

Node status and DFS

0

,2

,4

,6

,8

1

Cum

. Sur

viva

l

0 5 10 15 20 25 30 35 40Time

N +

N -

Tumor deposits & DFS

P=0.02

0

,2

,4

,6

,8

1

Cu

m.

Su

rviv

al

0 5 10 15 20 25 30 35 40Time

TD +(<3mm)

TD -

Downstaging & N +

P=0.03

-1

0

1

2

3

4

5

6

7

8

9

10

Nod

es in

vade

d

0 1

T downstaging & DFS

P=0.02

0

,2

,4

,6

,8

1

Cum

. S

urvi

val

0 5 10 15 20 25 30 35 40Time

Downstaging

No downstaging

Peri-tumoral inflammation & DFS

0

,2

,4

,6

,8

1

Cum

. S

urvi

val

0 5 10 15 20 25 30 35 40

Time

PTI +

PTI -

Now in need for more FU data from prof. Pattyn

References

1. Vanessa Deschoolmeester et al. MSI has no prognostic value in colon cancer in Belgian population. European Journal of Cancer 44 (2008) 2288-229

2. M. Nilbert et al. Microsatellite instability is rare in rectal carcinomas and signifies hereditary cancer. Eur. J. of Cancer, issue 6, June 1999, Pages 942-945

3. Terry Van Dyke. P53 and tumor suppression. N Engl J Med 356; 1 (2007)4. Jean-Franc¸ois Millau et al. P53 transcriptional activities: A general overview and

some thoughts. Mutation Research 681 (2009) 118–1335. Nadia N Naski et al. The p53 mRNA-Mdm2 interaction. Cell Cycle 8:1, 31-34 (2009)6. Christine M. Eischen and Guillermaina Lozano. P53 and MDM2: Antagonists or

Partners in Crime? Cancer Cell 15, march 3, 20097. Annelies Debucquoy et al. Morphological features and molecular markers in rectal

cancer from 95 patients included in the European Organization for Research and Treatment of Cancer 22921 trial: prognostic value and effects of preoperative radiochemo therapy. Eur. Journ. of Cancer 44 (2008) 791-797