Cancer BiologyCancer Biology

Tumour MarkersTumour Markers

Prof. Kenneth Bagshawe FRSProf. Kenneth Bagshawe FRS

Tumour MarkersTumour Markers Widest DefinitionWidest Definition

  The concept of tumour markers can The concept of tumour markers can mean anything that helps in the mean anything that helps in the diagnosis of cancerdiagnosis of cancer

In a more restricted sense it refers to In a more restricted sense it refers to the biochemical detection of cancerthe biochemical detection of cancer

Imaging TechniquesImaging Techniques

Detected by:Detected by:

x-ray +/- contrast mediax-ray +/- contrast media

    Ultra sound  Ultra sound  

Computerised Tomography (CT)Computerised Tomography (CT)

Magnetic resonance imaging (MRIMagnetic resonance imaging (MRI) )

    Gamma Camera and radioisotopes Gamma Camera and radioisotopes

(Nuclear Medicine)(Nuclear Medicine)

Cannon BallCannon Ball

Multiple MetastasesMultiple Metastases

Diffuse Metastases-Before and Diffuse Metastases-Before and After ChemotherapyAfter Chemotherapy

Detection of Tumour MarkersDetection of Tumour Markers

Those detected on cancer tissueThose detected on cancer tissue i) Biochemical methodsi) Biochemical methods Oestrogen receptors in breast cancerOestrogen receptors in breast cancer

ii) Genetic methodsii) Genetic methods Mutated genes BRCA1 and BRCA2 in breast cancerMutated genes BRCA1 and BRCA2 in breast cancer

iii) Antibody methodsiii) Antibody methods Carcinoembryonic antigen (CEA)Carcinoembryonic antigen (CEA)

Secreted by cancers into the blood Secreted by cancers into the blood

Detection byDetection by:: Biochemical techniquesBiochemical techniques steroids in adrenocortical cancer steroids in adrenocortical cancer  Immunoassay Immunoassay proteins, glycoproteinsproteins, glycoproteins

Ancient HistoryAncient History

1848 Bence Jones 1848 Bence Jones Multiple myelomaMultiple myeloma

1929 Ascheim-Zondek 1929 Ascheim-Zondek hCG-trophoblasthCG-trophoblast

1932 Harvey Cushing1932 Harvey Cushing Pituitary BasophilsPituitary Basophils

The First Tumour MarkerThe First Tumour Marker

It is known as Bence –Jones proteinuria, a It is known as Bence –Jones proteinuria, a marker for multiple myeloma a marker for multiple myeloma a

malignancy of the plasma cell.malignancy of the plasma cell.

Often referred to as a paraproteinuriaOften referred to as a paraproteinuria

It is a monoclonal gammopathy with any It is a monoclonal gammopathy with any class of immunoglobulinclass of immunoglobulin

Cancers of Endocrine OrgansCancers of Endocrine Organs

AdrenocorticalAdrenocortical PhaeochromocytomaPhaeochromocytoma

Insulinoma Insulinoma Gastrinoma Gastrinoma Carcinoid Carcinoid Medullary Ca ThyroidMedullary Ca Thyroid

CortisolCortisol adrenaline & nor adrenaline & nor

adrenalineadrenaline insulin, C peptide insulin, C peptide gastrin gastrin 5-HIAA 5-HIAA CalcitoninCalcitonin

Ectopic product syndromesEctopic product syndromes

Cancers sometimes produce substances Cancers sometimes produce substances inappropriate to the cell type of origininappropriate to the cell type of origin

   Bronchial carcinomas may produce Bronchial carcinomas may produce

ACTH, parathormone andACTH, parathormone and

human Chorionic Gonadotrophin (hCG)human Chorionic Gonadotrophin (hCG)

Protein markers of common cancers Protein markers of common cancers detected by immunossay in blooddetected by immunossay in blood

Human Chorionic gonadotrophin (hCG)Human Chorionic gonadotrophin (hCG)

PregnancyPregnancy Trophoblastic disease - ChoriocarcinomaTrophoblastic disease - Choriocarcinoma Germ cell cancers of testis and ovaryGerm cell cancers of testis and ovary   Alfa- feto protein (AFP)Alfa- feto protein (AFP)

Germ cell cancers of testis and ovary Germ cell cancers of testis and ovary

HepatomaHepatoma

  

Protein markers continuedProtein markers continued

Carcinoembryonic antigen (CEA)Carcinoembryonic antigen (CEA)

Colon, stomach etcColon, stomach etc

Prostate Specific antigen (PSA)Prostate Specific antigen (PSA)

CA125- OvaryCA125- Ovary

CA153- BreastCA153- Breast

Measurement of Tumour MarkersMeasurement of Tumour Markers

1930-1963 Bioassays on Urine1930-1963 Bioassays on Urine 1958 Immunoassays- serum1958 Immunoassays- serum 1960 Radioimmunoassay-1960 Radioimmunoassay- serum or urineserum or urine 1968 Immunometric assay1968 Immunometric assay serum or urine-serum or urine- Commercial KitsCommercial Kits 1975 Dip Stick Tests1975 Dip Stick Tests

What Is An Assay ?What Is An Assay ?

0

200000

400000

600000

800000

0 0.002 0.004 0.006 0.008 0.01

Concentration of Reference Standard

Res

po

nse Unknown

Antibody ProductionAntibody Production

Immunogen (Antigen) RabbitImmunogen (Antigen) Rabbit Sheep AntiserumSheep Antiserum MouseMouse Horse etcHorse etc

Antisera contain many different antibodies directed at Antisera contain many different antibodies directed at one or more sites on immunogen (polyclonal)one or more sites on immunogen (polyclonal)

Burnett (1957)- Clonal selection TheoryBurnett (1957)- Clonal selection Theory One Cell - identical antibodiesOne Cell - identical antibodies

Antibody ProductionAntibody Production

Kohler & Milstein (1975) Kohler & Milstein (1975) Immortalise an antibody producing Immortalise an antibody producing

cell cell by fusion with a malignant cellby fusion with a malignant cell

HybridomaHybridoma Hybridomas proliferateHybridomas proliferate Identical (monoclonal) antibodies Identical (monoclonal) antibodies

RISING levels of these serum markers RISING levels of these serum markers

indicate disease progressionindicate disease progression

FALLING levels and slowing of rate of FALLING levels and slowing of rate of increase may indicate response to increase may indicate response to therapytherapy

   BUT interpretation has to take account BUT interpretation has to take account

of the HALF -LIFE (t1/2)of the HALF -LIFE (t1/2)

  

Half Life Of Common Tumour Markers Half Life Of Common Tumour Markers Depends On Molecular WeightDepends On Molecular Weight

MW TM T1/2(D) ROUTEMW TM T1/2(D) ROUTE <70 hCG, PSA 2.3 renal<70 hCG, PSA 2.3 renal 70 aFP 6 mixed70 aFP 6 mixed   > 70 all others 10 hepatic > 70 all others 10 hepatic   

Median Doubling TimesMedian Doubling Timesreflect different growth rates of cancersreflect different growth rates of cancers

CANCER TM T2(D)CANCER TM T2(D) Choriocarcinoma hCG 3Choriocarcinoma hCG 3 Germ cell aFP 6Germ cell aFP 6 Breast CA153, CEA 30Breast CA153, CEA 30 Ovary CA125 30 Ovary CA125 30 Pancreas CA199 30Pancreas CA199 30 Colon CEA, CA199 30Colon CEA, CA199 30 Prostate PSA 128 Prostate PSA 128   

Cell NumbersCell Numbers

Time Scale- Cell NumbersTime Scale- Cell Numbers

Human Chorionic Gonadotrophin-Human Chorionic Gonadotrophin-(HCG) C-Terminal Peptide(HCG) C-Terminal Peptide

Normal Placental VilliNormal Placental Villi

hCG V Cell NumbershCG V Cell Numbers

Human Chorionic Human Chorionic Gonadotrophin (hCG)Gonadotrophin (hCG)

Normal Pregnancy: Normal Pregnancy:

Mostly Intact molecule (Mostly Intact molecule (αα and and ββ subunits) subunits)

Mole, Choriocarcinoma: Mole, Choriocarcinoma:

Fragmented hCG moleculesFragmented hCG molecules

Trophoblastic TumourTrophoblastic Tumour

ChoriocarcinomaChoriocarcinoma

Germ Cell TumourGerm Cell Tumour

Germ Cell TumourGerm Cell Tumour

Prostate Specific Antigen (PSA): Age Effect

Carcinoembryonic AntigenCarcinoembryonic Antigen

CEACEA

Radioimmunolocalisation-CEARadioimmunolocalisation-CEA

Therapeutic ApplicationTherapeutic Application

Radiolabelled Antibodies (RIT)Radiolabelled Antibodies (RIT)

Drug-Antibody ConjugatesDrug-Antibody Conjugates

ProblemsProblems

Only a fraction of the i.v injected antibody Only a fraction of the i.v injected antibody gets into tumour: gets into tumour:

Most of the antibody stays in blood until Most of the antibody stays in blood until excreted or metabolisedexcreted or metabolised

Heterogeneity of cancer cell:Heterogeneity of cancer cell:

not all cancer cells express the markernot all cancer cells express the marker

Potential SolutionsPotential Solutions

Antibody directed enzyme prodrug Antibody directed enzyme prodrug therapy (ADEPT)therapy (ADEPT)