Predictive Value and Therapeutic Significance of Somatic BRCA Mutation in Solid Tumors

Role of PARP Inhibitors: A New Hope for Breast Cancer Therapy

Tumors formed by the unchecked growth of breast cells are known as breast cancer. The second most frequent cancer in the world is breast cancer. It is the most common cancer among females. In 2022, 2,296,840 women were diagnosed with breast cancer. The therapy of breast cancer is evolving through the development of Poly (ADP-ribose) polymerase (PARP) inhibitors, which are offering people with specific genetic profiles new hope as research into the disease continues. It focuses on patients with BRCA1 and BRCA2 mutations. This review summarizes the most recent research on the mechanisms of action of PARP inhibitors and their implications for breast cancer therapy. We review how therapeutic applications are developing and highlight recent studies showing the effectiveness of these medicines whether used alone or in combination. Furthermore, the significance of customized therapy is highlighted in enhancing patient outcomes as we address the function of genetic testing in identifying candidates for PARP inhibition. Recommendations for future research areas to maximize the therapeutic potential of PARP inhibitors are also included, along with challenges and limits in their clinical usage. The objective of this review is to improve our comprehension of the complex interaction between breast cancer biology and PARP inhibition. This knowledge will help to guide screening approaches, improve clinical practice, and support preventive initiatives for people at risk.

The Landscape of PARP Inhibitors in Solid Cancers

PARP inhibitors are a class of agents that have shown significant preclinical activity in models defective in homologous recombination (HR). The identification of synthetic lethality between HR defects and PARP inhibition led to several clinical trials in tumors with known HR defects (initially mutations in BRCA1/2 genes and subsequently in other genes involved in HR). These studies demonstrated significant responses in breast and ovarian cancers, which are known to have a significant proportion of patients with HR defects. Since the approval of the first PARP inhibitor (PARPi), olaparib, several other inhibitors have been developed, expanding the armamentarium available to clinicians in this setting. The positive results obtained in breast and ovarian cancer have expanded the use of PARPi in other solid tumors with HR defects, including prostate and pancreatic cancer in which these defects have been identified. The clinical trials have demonstrated responses to PARPi which are now also available for the subset of patients with prostate and pancreatic cancer with HR defects. This review summarizes the results obtained in solid tumors with PARPi and their potential use when combined with other agents, including immune checkpoint inhibitors that are likely to further increase the survival of these patients which still needs a dramatic improvement.

Efficacy and safety of different angiogenesis inhibitors combined with PARP inhibitors in the treatment of ovarian cancer: A systematic review and meta‑analysis

Ovarian cancer is a leading cause of mortality among women with gynecological malignancies, largely due to its asymptomatic nature in early stages and frequent late diagnosis. Targeted therapies, such as angiogenesis inhibitors and poly(ADP-ribose) polymerase inhibitors (PARPi), have emerged as promising treatments by disrupting tumor vasculature and impairing DNA repair mechanisms, particularly in patients with BRCA mutations. The objective of the present study was to comprehensively evaluate the combined use of different angiogenesis inhibitors and PARPi in ovarian cancer treatment by meta-analysis. This included assessing their impact on objective response rate (ORR) and progression-free survival (PFS), understanding the role of BRCA mutation status, and comparing the effects of various angiogenesis inhibitors when used in combination with PARPi. The PubMed, Embase and Cochrane databases were searched from inception to February 2024. Only studies on the combined treatment of ovarian cancer with angiogenesis inhibitors and PARPi were included. Duplicate studies, studies with incomplete data, animal studies, literature reviews and systematic studies were excluded. The results underscored a noteworthy improvement in the ORR and median PFS (mPFS) among patients receiving combination therapy compared with those on monotherapy. Specifically, the pooled ORR for combination therapy was significantly higher than that of monotherapy, indicating a substantial benefit in terms of tumor response. Furthermore, combination therapy was found to significantly prolong PFS, offering patients a longer duration without disease progression. Subgroup analyses of patients treated with angiogenesis inhibitors combined with PARPi provided deeper insights, revealing that patients with BRCA mutations exhibited an ORR of 90% compared with 61% in those without BRCA mutations. Additionally, when different angiogenesis inhibitors were compared, patients treated with anti-VEGF agents combined with PARPi showed a longer mPFS (15.53 months) than those treated with TKIs combined with PARPi (7.49 months). In conclusion, the present study demonstrates that combinations of angiogenesis inhibitors and PARPi show great potential for improving treatment outcomes in ovarian cancer, particularly in patients with BRCA mutations. The observed differences in efficacy between various angiogenesis inhibitors highlight the importance of personalized treatment approaches. Further research is warranted to explore the long-term benefits of these combination strategies and refine them to obtain optimal patient outcomes.

Benign polymorphisms in the BRCA genes with linkage disequilibrium is associated with cancer characteristics

Germline pathogenic mutation of the BRCA gene increases the prevalence of breast cancer. Reports on the benign variants of BRCA genes are limited. However, the definition of these variants might be altered with the accumulation of clinical evidence. Therefore, in the present study, we focused on benign single nucleotide polymorphisms (SNPs) of BRCA genes. Linkage disequilibrium was calculated from whole genome sequencing of the BRCA genes obtained from 500 healthy controls and 49 breast cancer patients. Sanger sequencing was used to confirm the mutation. The linkage disequilibrium was noted for seven and three SNPs in the BRCA1 and BRCA2 genes, respectively. Breast cancer with BRCA1/2 linkage disequilibrium was not correlated with a personal history of benign diseases or family history of cancer. Nevertheless, breast cancer with BRCA1 linkage disequilibrium was correlated with high tumor-infiltrating lymphocytes and positive extensive intraductal components. The patients with BRCA1 linkage disequilibrium tended to have worse disease-specific survival. Cancers with BRCA2 linkage disequilibrium are associated with a lower ratio of grade III cancer. Moreover, patients with BRCA2 linkage disequilibrium tended to have better overall survival. In conclusion, linkage disequilibrium from benign SNPs of the BRCA genes potentially affects cancer characteristics.