Biomarkers in cancer research
Biomarkers have been particularly useful in cancer research. Cancer biomarkers are used to diagnosis patients,
determine prognosis, develop a targeted therapy, and monitor treatment response. Early screening for cancer biomarkers can catch disease early, enabling more effective treatment and increasing survival rate. Early treatment targets may eventually be used to develop cancer preventions.
Sensitivity and specificity of biomarkers play a key role in targeted therapies. One sensitive biomarker is called minimal residual disease (MRD). MRD is when a small number of cancer cells remains in the patient’s blood during or after treatment.
MRD can lead to cancer relapse. Liquid biopsy, or blood screening, paired with NGS can detect minute numbers of cancer cells and determine whether the treatment has completely eradicated the cancer. Presence or absence of MDR detected by liquid biopsy
testing can also be used to track the efficacy of treatment and adjust the therapy the patient is receiving.
One specific cancer type that has benefited from biomarker discovery is breast cancer. Breast cancer affects over 300,000 women each year and is the second most common cause of death from cancer for women (www.cancer.net/cancer-types/breast-cancer/statistics).
The disease also can affect men, albeit at a much lower incidence. Although mammography is routinely used to screen for cancerous lesions, some families harbor genetic mutations in the BRCA (BReast CAncer gene) genes. Every person’s
genome contains the BRCA1 and BRCA2 genes, which produce proteins that repair damaged DNA. Mutations in one or both genes increase the risk of developing breast or ovarian cancer due to the loss of the repair pathway.
Several molecular diagnostic tests are available to look for mutations in BRCA1 and BRCA2, as well as, in an increasing number of genes that have been identified as potentially harboring driver mutations for other cancers. Although these
tests were traditionally done with PCR-based analysis, the decreasing cost of NGS has increased its use as a diagnostic tool. In addition to the decreased cost, NGS results clearly define the type and scope of the genetic mutation(s) in a wide panel
of genes. With over 70,000 scientific articles published since 2018 with the term “cancer biomarker” according to Google Scholar, new and different biomarkers are being discovered at an incredible pace. It is important for any NGS-based
diagnostic panel to be modular, allowing for additions and subtractions of various genetic mutations as research dictates.