The study find that the Immune response of tumors in patients with BRCA 1/2-related breast cancers. Therefore The research; published in the journal Clinical Cancer Research; could shape treatment strategies and clinical trial design for these patients; who make up about two% of newly diagnosed cases of breast cancer.
Shape treatment strategies
“This study helps to highlight the immune characteristics of BRCA1/2 breast cancers and to identify the molecular features that may predict immunogenicity;” said the study’s senior author Katherine L. Nathanson, MD, Pearl Basser Professor for BRCA-Related Research at the Abramson Cancer Center of the University of Pennsylvania.
“These data provide a strong building block for our work in uncovering the biological mechanisms that may inform treatment response for patients with BRCA1/2-related breast cancers. Because Each time we uncover new information that could help tailor the most effective treatments for each patient; we see it as a positive step forward.”
The molecular features
Checkpoint inhibitors are a popular immune therapy cancer treatment for some types of cancers and currently are being studied in clinical trials to test the efficacy in treating BRCA1/2 breast cancers. Researchers sought to determine whether specific genomic markers could provide clues about the immune environment in BRCA1/2 mutation-associated breast cancers. To do so, the team analyzed genomic data from the Cancer Genome Atlas (TCGA) ;to compare breast cancers with (89) and without (770) ; either germline (inherited) or somatic (acquired) BRCA1/2 mutations.
They also studied 35 breast cancers with germline BRCA1/2 mutations from Penn patients using whole exome sequencing (WES) and immuno histo chemistry. It has been hypothesize that breast cancers with somatic or germline BRCA1/2 mutations may be more responsive to checkpoint blockade due to their relatively higher mutational burden.
The immune environment
Nevertheless, in this study; researchers found that a higher frequency of mutations was associated with lower immune infiltration of tumors; suggesting that BRCA1/2 mutation status may not be directly predictive of response to checkpoint blockade.
The team found that higher levels of genomic instability, as measure by homologous recombination deficiency (HRD), were associated with lower immunogenicity and tumor infiltration by T cells. These results were unexpect and go against conventional clinical wisdom. “One aspect of the study that was particularly interesting was that it builds upon our prior studies.
Previously we found that tumors in germline BRCA1/2 mutation carriers that did not lose the wild type allele were likely to be less sensitive to DNA damaging agents, and our new data suggests they may be more sensitive to checkpoint blockade,” Nathanson said.