Tumour Markers

1. Dr.JALAJ GAUTAM
TUMOUR MARKERS
AND THEIR SIGNIFICANCE

2. WHAT ARE TUMOUR MARKERS
 Tumour Markers are biological substances
synthesized and released by the tumour cells or by
the host body in response to a tumour.
 Detected in higher than normal levels in blood,
serum, urine or other body fluids.
 Indicators of cellular, biochemical, molecular, or
genetic alterations whereby neoplasia can be
recognised.
 Found to be raised in certain benign conditions also
and hence, elevated levels need to be interpreted
with caution.

3. HISTORICAL BACKGROUND
1863 Bence Jones Protein
1940 Acid Phosphatase
1960 Immunoassay
1963 -Fetoprotein
1965 Carcinoembryonic Antigen
1975 Monoclonal Antigens
1980 CA 125, PSA, Carbohydrate
Antigens
1970 Oncogenes
1980 Tumour Suppressor Genes
2001 Microarrays, Mass Spectrometry,
Neural Network, Multiparametric
Analysis

4. CLINICAL APPLICATIONS
 Screening.
 Diagnosis.
 Staging.
 Prognosis.
 Therapy.
 Surveillance and monitoring.

5. Screening
 Best example is the screening of prostate cancer
with serum PSA.
 Apart from PSA, no other tumour markers have
shown reliability for the purpose of screening.
 Major disadvantage being the overdiagnosis and
overtreatment of a certain tumour based on
screening with tumour markers.
 Some recent studies, like ERSPC and PLCO
trials didn’t show any significant mortality benefit
even in prostate cancer screened with PSA level.
Only one in eight screen-detected cancers is
likely to kill the patient.

6. Diagnosis and Staging
 Tumour markers doesn’t help in establishing the
diagnosis per se in most of the cases but
corroborates it.
 Helps in distinguishing benign from malignant
cases in some tumours.
 Correlates with amount of tumour present and
hence, identifies the tumour burden.
 Sometimes, allow subtype classification and
hence helps in staging of the disease.

7. Prognosis, Therapy and Monitoring
 The mere presence or absence of a tumor marker
or its quantification helps in determining the
prognosis.
 Predicts the response to therapy and hence
guides the choice of therapy in many cases.
 The newer modality of targeted therapy is based
on the presence or absence of such markers.
 Identifies the response to therapy with change in
levels.
 Helps in the monitoring for recurrences in follow-
up.

8. THE IDEAL TUMOUR MARKER
 High sensitivity and specificity.
 Level should correlate with the tumour burden.
 Levels in healthy patient should be much lower
than that in a cancer patient.
 Predict recurrences before they are clinically
detectable.
 The tumour marker assay should be reducible,
rapid, and inexpensive.

9. CATEGORIES OF TUMOUR MARKER
 Protein:
o Oncofetal antigens – CEA, AFP.
o Hormones – HCG, Calcitonin, Catecholamine and
its metabolites, Ectopic hormones.
o Isoenzymes – Neuron specific enolase, Acid
phosphatase.
o Mucin and other glycoprotiens – CA-19-9, CA-
125, CA-15-3.
o Specific proteins – Immunoglobulins, PSA.
 RNA based markers:
o Overexpressed or underexpressed transcripts.
o Regulatory RNAs (e.g., micro-RNAs)

10.  DNA-based markers:
• Single nucleotide polymorphisms (SNPs).
• Chromosomal translocation – bcr-abl (Philadelphia).
• Microsatellite instability.
• Changes in DNA copy number.
• Epigenetic changes(e.g., differential promoter-
region methylation)

11. DETECTION OF TUMOUR MARKER
 Serological: Enzyme assays.
 Immunological:
 Immunohistochemistry (IHC).
 Immunosorbent assay.
 ELISA.
Radioimmuno assay.
 Cytogenetic analysis:
FISH.
Spectral karyotyping.
Comparative genomic hybridization.

12.  Genetic analysis:
Sequencing.
Reverse transcription.
Gel electrophoresis.
DNA micro-array analysis.
 Polymerase Chain Reaction
 Proteomics:
Surface-enhanced laser
desorption/ionization.

13. CARCINOEMBRYONIC
ANTIGEN
 Complex glycoprotein that is associated with the
plasma membrane of tumor cells, from which it may
be released in to the blood.
 Mainly used for colorectal cancer but may be
elevated in:
 Smokers
 Some benign conditions – IBD, pancreatitis,
cirrhosis, COPD etc
 Other malignant lesions – ovarian, breast,
pulmonary.
 Normal <2.5 ng/ml, Borderline 2.5-5.0 ng/ml,
Elevated >5 ng/ml.
 Upper limit of normal level in smokers considered to
be 5 ng/ml.

14.  Not useful for screening purposes as higher rate of
false positive results seen and low sensitivity in early
cases.
 Elevated level reflects tumour burden.
 More the concentration:
Worse the prognosis.
Higher the chances of recurrence.
 More sensitive for hepatic and retroperitoneal
metastases. Relatively insensitive for local
recurrences and pulmonary or peritoneal
metastases.
 Monitors response to chemotherapy in metastatic
disease.

15. α -Fetoprotein
 Used for Hepatocellular carcinoma and non-
seminomatous testicular tumour.
 Elevated in benign conditions like cirrhosis, acute
and chronic hepatitis, 2nd and 3rd trimester of
pregnancy and IBD.
 Other malignant conditions show elevation and
include pancreatic, gastric, colorectal or lung
cancer.
 Upper limit of normal value in non-pregnant adult
is <25ng/ml.
 No detectable level in upto 20% of HCC cases.
 Level correlates with tumour burden, staging and
hence prognosis.

16.  Prognosis not only depend on the initial
concentration but also the rate of its rise called
the AFP doubling time.
 Level decreases with resection or ablation and
hence marks response to the therapy. Level
should decrease and remain below 10 ng/ml.
 Maintenance of a higher level after treatment
predicts early recurrence.

17. Carbohydrate Antigen 19-9
 Serum marker for pancreatic cancer.
 Lewis a negative blood group patients don’t
produce this antigen and hence can’t be used in
this group that consists of 10% of population.
 Also elevated in benign biliary tract diseases,
acute and chronic pancreatitis.
 Elevated in malignant lesions of biliary tract
(95%), stomach, liver, colon and lung.
 For above reasons, use is limited to monitoring of
response to therapy, not as a diagnostic marker.
 Level correlates with tumour burden and hence
marks prognosis.

18. Prostate Specific Antigen
 Formed in prostatic epithelium and secreted in
prostatic ducts.
 Highly specific tissue marker for prostate but not a
specific cancer marker as level is elevated in
benign prostatic diseases.
 Not only the level but the rate of increase of the
level (PSA velocity) and its concentration per unit
volume of prostatic tissue (PSA density) is also
important.
 Normal upper limit varies with the age of the
patient.
 Only tumour marker widely used for screening
purposes.

19. Carbohydrate Antigen 125
 Normally present in the fetus as a derivative of
coelomic epithelium.
 In healthy adults, detected in epithelium of
fallopian tubes, endometrium and endocervix.
 Upper limit of normal 35 U/ml
 Elevated in benign conditions like PID,
endometriosis, adenomyosis, fibroids, cirrhosis
and ascites.
 Elevated in ovarian carcinoma and cancer of
fallopian tube, endometrium and cervix. Non
gynaec malignancies including pancreas, colon,
lung and liver also have elevated level.

20. β - HCG
 Glycoprotein synthesized from the
syncytiotrophoblastic cells of normal placenta.
 Level is elevated in early pregnancy with peak in
the first trimester.
 Elevated in gestational trophoblastic neoplasia-
choriocarcinoma.
 Elevated in non-seminomatous testicular germ cell
tumours and constitute an important tumour
marker for testicular malignancies alongwith AFP,
LDH and PLAP.

21. Chromogranin A (CgA)
& Neuron-specific Enolase (NSE)
 Normal serum value: <76 ng/mL in men and < 51 ng/mL in
women.
 Malignancies: In Neuroendocrine tumors, Carcinoid tumors,
Neuroblastoma, Small cell lung cancer, Pancreatic islet cell
tumors, Prostate cancers
 It is probably the most sensitive tumor marker for carcinoid
tumors, being abnormal in 33 % cases with localized
disease and 66 % of those with metastatic cancer.
 The sensitivity and specificity are approximately 92% and
96% respectively fairs better than NSE.

22. Estrogen receptors/Progesterone receptors
 Breast cancer tissues are commonly tested for these markers by
IHC.
 Breast cancers that contain estrogen receptors are often referred to
as “ER positive,” while those with progesterone receptors are “PR
positive.” (>10Fmol is +ve)
 Their main use is as a predictor of prognosis (survival outlook).
 About 7 out of 10 breast cancers test positive for at least one of
these markers.
 These cancers tend to have a better prognosis than cancers without
these receptors and are much more likely to respond to hormonal
therapy such as tamoxifen or aromatase inhibitors.
 > 60% 0f ER + & < 10 % of ER - tumors respond.
 Degree of positivity is proportional to grade & histology.

23. Estrogen Receptor (ER)
 2 isoforms：ERa and ERb
 ERa → better prognosis, predictor of relapse
 useful when deciding on adjuvant hormone treatment
 As diagnostic marker when it is a primary unknown
tumor
 ERb → Good prognostic factor, correlates with low
grade and negative axillary LN status tumours.

24.  HER-2/neu oncogene (using monoclonal
antibody) - over expression related to poor
prognosis in breast cancer
 Oncogene c-erbB-2 gene：over expressed in 30%
of breast cancers, correlation between c- erbB-2 gene
positivity, positive axillary node status, reduced time
to relapse and reduced overall survival.
 BRCA1 gene on chromosome 17q：familial
breast-ovarian cancer syndrome, and breast
cancer in early-onset breast cancer families.
BREAST CANCER ONCOGENE

25. • Tomonitor treatment & to detect recurrence.
• Increase in 20% with localized breast cancer, ~80%
withmetastatic disease, esp. if with bone involvement
• Specificity of 86%, sensitivity of 30%
• Also increase in gastric, pancreatic, cervical & lung
cancer.
Other common tumour markers
 Calcitonin – medullary carcinoma of thyroid.
 Thyroglobulin – follicular carcinoma of thyroid.
 S-100, Tyrosinase – Malignant melanoma.
 Other DNA and RNA basedmarkers.
BREASTCANCER& CA15-3

26. Immunoperoxidase Tumor Staining
 Most widely available specialised technique for
classification of neoplasms.
 Can be done on fresh tissue, cytology smears, formalin-
fixed paraffinised tissue.
 Antibodies (monoclonal/ polyclonal) are directed at cell
components/ products, which include enzymes (PSA,
NSE), normal tissue components (keratin, desmin,
vimentin, CLA), hormones & hormone receptors (ER, PgR),
 onco-fetal antigens (a-fetoprotein, AFP), CEA, S-100 and
proteins.