How Do Cancer Biomarkers Indicate the Existence of Cancer?

A cancer biomarker is a substance or mechanism in the body that indicates the existence of cancer. A biomarker is a substance released by a tumor or a particular bodily reaction to the presence of cancer. Cancer diagnosis, prognosis, and epidemiology can all benefit from genetic, epigenetic, proteomic, glycomic, and imaging biomarkers. The optimal way to test such markers is in non-invasively collected biofluids like blood or serum.

While there are numerous challenges in translating biomarker research into the clinical space, a number of gene and protein-based biomarkers have already been used in patient care, including AFP (liver cancer), BCR-ABL (chronic myeloid leukemia), BRCA1 / BRCA2 (breast/ovarian cancer), BRAF V600E (melanoma/colorectal cancer), CA-125 (ovarian cancer), CA19.9 (for pancreatic cancer), CEA Because they can only derive from an existing tumor, mutant proteins discovered by selective reaction monitoring (SRM) have been claimed to be the most specific biomarkers for malignancies. Cancer can be treated in around 40% of cases if found early through tests.

The term “biomarker” is defined differently by different organizations and publications. Biomarkers are proteins that may be identified or measured in the blood or urine in various fields of medicine. However, the phrase is frequently used to refer to any quantifiable or measurable molecular, biochemical, physiological, or anatomical characteristic.

According to the National Cancer Institute (NCI), a biomarker is “a biological molecule present in blood, other bodily fluids, or tissues that is an indication of a normal or aberrant activity, or of a condition or illness.” A biomarker can be used to assess how effectively the body reacts to a disease or condition therapy. Also known as a molecular marker and a signature molecule.”

Biomarkers are utilized in three ways in cancer research and medicine:

• To assist in the diagnosis of illnesses, such as recognizing early stage malignancies (diagnostic)
• To anticipate the severity of an illness, as in assessing a patient’s capacity to survive in the absence of treatment (prognostic)
• To forecast a patient’s response to therapy (predictive)

Types of cancer biomarkers

Breast

• ER/PR (Estrogen receptor/Progesteron receptor)
• HER-2/neu (Human epidermal growth factor receptor 2) (Neuroglioblastoma cell line)

Colorectal

• EGFR (Epidermal growth factor receptor)
• KRAS (Kirsten rat sarcoma virus)
• UGT1A1 (UDP glucuronosyltransferase family 1 member A1)

Gastric

HER-2/neu (Human epidermal growth factor receptor 2) (Neuroglioblastoma cell line)

Gastrointestinal stromal tumor

c-KIT

Leukemia/lymphoma

• CD20 (Cluster of differentiation)
• CD30 (Cluster of differentiation)
• FIP1L1-PDGFRalpha
• PDGFR (Platelet-derived growth factor receptors)
• Philadelphia chromosome (BCR/ABL)
• PML/RAR-alpha
• TPMT
• UGT1A1

Lung

• EML4/ALK (Echinoderm microtubule associated protein /4-anaplastic lymphoma kinase)
• EGFR (Epidermal growth factor receptor)
• KRAS (Kirsten rat sarcoma virus)

Melanoma

BRAF (B-Raf)

Pancreas

Elevated levels of leucine, isoleucine and valine, Essential amino acids called branched-chain amino acids (BCAA) are used in both anabolic and catabolic metabolism. Recent evidence reveals that BCAA metabolism plays a significant role in cancer, despite being extensively investigated in obesity and diabetes. An increased risk of developing pancreatic cancer, specifically pancreatic ductal adenocarcinoma (PDAC), a malignancy with one of the highest 1-year fatality rates, is linked to elevated plasma levels of BCAA.

Ovaries

CA-125 test quantifies the blood’s concentration of the CA 125 (cancer antigen 125) protein. This examination could be used to keep a watch on some malignancies both during and after treatment. The test may occasionally be used to screen for early indications of ovarian cancer in women who have a very high risk of developing the disease.

Other examples of biomarkers:

• Because they serve in repairing DNA breaks that can cause cancer, these genes are actually referred to be “tumour suppressor genes.” Examples: BRCA1, BRCA2 (Breast cancer gene type 1/Breast cancer gene type 2)
• RNA Examples: mRNA, microRNA
• Proteins found in body fluids or tissue. Examples: PSA (Prostate-specific antigen) and CA-125
• Antibodies to cancer antigens. Examples: Merkel cell polyomavirus
• DNA. Examples: Circulating Tumor DNA (ctDNA)

References

1.    https://pubmed.ncbi.nlm.nih.gov/22542320/

2.    https://pubmed.ncbi.nlm.nih.gov/30502682/

Author

 Yash Batra