Biomarker testing provide detailed information of a tumor’s molecular
characteristics. That information can point to therapies that may have the best chances for positive outcomes. This information is discovered by testing the tumor for biomarkers such as homologous recombination deficiency (HRD), micro-satellite status (MS), and tumor mutation burden (TMB), as well as molecular changes in more than 300 genes. You might ask your doctor if this testing has been ordered for you.
Tumor biomarker testing can be informative for people who are newly diagnosed and do not have an inherited BRCA gene mutation identified by a genetic test of their blood. A BRCA mutation can sometimes be detected in the tumor but not the blood (called “somatic”) and this testing can determine if the tumor is positive. Patients who are BRCA positive in either of these tests may benefit from a PARP inhibitor as maintenance therapy after first line.
A positive HRD test result also suggests that a PARP inhibitor could be very effective. HRD testing provides an estimate of the “BRCAness” characteristic of the tumor by measuring the genomic instability that results from problems with DNA damage repair. This increased damage occurs in tumors that do not have a functional BRCA protein (e.g., due to a mutated BRCA gene) and also occurs when the BRCA gene is fine and the BRCA protein is not made by the cancer cell or when other genes in this repair pathway are mutated. The tumor looks like BRCA is not working properly and the HRD test is positive. Studies show that people whose tumors are HRD positive may receive more benefit from PARP inhibitor treatment in maintenance or recurrence than those whose tumors are HRD negative (also called HRP for homologous recombination proficient).
For people with recurrent or refractory ovarian cancer, tumor biomarker testing can provide important new information to help guide their next treatment. In some cases, there is an approved drug for patients with specific biomarkers found in their tumor. In other cases, the presence of specific genomic changes are requirements for patients to enroll in some clinical trials that are testing drugs that are predicted to work for them.
The Clearity Foundation can help patients understand the results from the tumor biomarker testing and comprehensive genomic analysis that is ordered by their physicians. Patients have access to Clearity’s staff, who have expertise in ovarian cancer molecular and cellular biology and can help them understand their results and the unique nature of their cancer, as well as potential treatments and clinical trial options.
Clearity does not provide medical advice about which treatments they should receive. Instead, our staff explain tumor biomarker test results and provide potential questions, and other information, which patients can discuss with their physicians.