Tumor Markers

Cancer is a disease caused by uncontrolled growth of cells that often form a new solid mass or tumor AKA

Neoplasma

Cancer causing genes are called…

Oncogenes

Tumor markers encompass an array of diverse molecules like:

Oncofetal antigens, Hormones, Metabolites, Receptors, Enzymes

What are oncofetal antigens?

A protein produced during fetal development and elevated in individuals with cancer (AFP or CEA)

Where is PSA (Prostate specific antigen) produced?

It is produced by the epithelial cells of the prostate gland

What is the normal role of PSA?

Helps liquefy semen and improve motility

How is PSA distributed in the blood?

PSA circulates in serum in both free and protein bund forms

Which form of PSA is most commonly measured clinically?

Total PSA (free + bound), with additional use of free for diagnostic value

What does a lower free PSA fraction suggest?

Higher likelihood of cancer. (fPSA/tPSA) x 100. A %fPSA less than 25% detects 95% of cancer

What is NSE (neuron-specific enolase)?

An isoenzyme of enolase found in neurons and neuroendocrine cells, involved in glycolysis

In which type of cancers is NSE commonly elevated?

Neuroendocrine tumors, especially small cell lung carcinoma

In what conditions are the pregnancy human chorionic gonadotropin (hCG) elevated, other than pregnancy?

• Ovarian cancer

• Testicular cancer

What are two Oncofetal antigens?

Alpha Fetoprotein (AFP) and CEA (Carcinoembryonic antigen)

What is AFP normally produced by in the fetus?

The fetal liver and yolk sac

What is the main clinical use of AFP?

Tumor marker for diagnosis and monitoring of liver cancer and germ cell tumors

What is CEA normally associated with?

Fetal GI tissue

In which conditions is CEA commonly elevated?

Colorectal cancer, pancreatic, gastric, lung, breast cancers

What is CA-125 and what is its basic nature?

A large glycoprotein expressed on coelomic epithelium derived tissues

What is CA-125 mainly used as a markers?

Epithelial ovarian cancer

What is Episalin (Ep-CAM)?

An epithelial cell adhesion molecule (glycoprotein)

In which cancers is Episalin commonly overexpressed?

Many epithelial cancers including colorectal, breast, prostate, and ovarian cancers

What is the genetic markers HER -2/neu?

A proto-oncogene that codes fora transmembrane tyrosine kinase receptor involved in cell growth signaling

In which cancers in HER -2/neu commonly overexpressed?

Breast and gastric cancer

What are BRCA 1 and 2 genes?

Tumor suppressor genes involved in DNA repair

What happens when BRCA 1 and 2 are mutated?

Impaired DNA repair leading to genomic instability and increased cancer risk

Which cancers are strongly associated with BRCA 1 and 2 mutations?

Breast and ovarian cancers

Markers for Breast cancer

CA 15-3

Markers for Liver cancer

AFP

Markers for Pancreatic cancer

CA 19-9

Markers for Colon/GI cancer

CEA

Markers for Ovarian cancer

CA-125 and HE4

Markers for Prostatic cancer

PSA

Markers for Testicular cancer

hCG and AFP