Cancer cell mutations and their impact on response to treatment

The authors aimed to determine the significance of cancer cells mutations (a permanent change in the genetic core of the cell) and their impact on a patient’s eligibility for certain therapy drugs.

Tumor suppressor genes (such as BRCA-1) protect cells from becoming cancerous through mechanisms that repair damage done to DNA. Mutations can occur in these genes, however, and the impact can be a higher risk of developing breast cancer. Many triple-negative breast cancers (TNBC; cancer cells are negative for both estrogen and progesterone hormone receptors and human epidermal growth factor receptor 2) are caused by mutations. Breast cancers caused by these mutations can also be difficult to treat.

Cancers caused by mutations may be particularly susceptible to treatment with certain types of chemotherapy (including platinum drugs) and PARP inhibitors (a type of cancer treatment drug). Therefore, it is important to understand the prevalence of DNA repair mutations in patients with or without TNBC.

This study was aimed at evaluating the prevalence of cancer cell mutations in specific cancer sub-types.

There were two groups of women evaluated; 158 women with TNBC and 44 women with non-triple negative breast cancer (non-TNBC). Patients were tested for mutations in common DNA repair genes.

22.2% of those with TNBC and 22.7% of those with non-TNBC had mutations in the genes involved in DNA repair. In those with TNBC, BRCA1 mutations were most frequent (18.4%), whereas in those with non-TNBC, CHEK2 mutations were most frequent (15.9%).

Mutations were more common in patients with early-onset breast cancer (before age 50). In this age group, DNA repair gene mutations were found in 35.2% of those with TNBC and 33.3% of those with non-TNBC. 

The authors suggested that determining the presence of cancer gene mutations can determine the likelihood a patient will respond to platinum chemotherapy drugs or PARP inhibitors.

This study involved a small group of patients.

Consult your doctor about being tested for mutations such as BRCA2 or CHEK2. Determining a cancer cell mutation could pre-determine whether or not you would benefit from treatments such as PARP inhibitors or platinum drugs.