Comprehensive analysis of DNA damage repair genes reveals pathogenic variants beyond BRCA and suggests the need for extensive genetic testing in pancreatic cancer

Prevalence of a BRCA2 Pathogenic Variant in Hereditary-Breast-and-Ovarian-Cancer-Syndrome Families with Increased Risk of Pancreatic Cancer in a Restricted Italian Area

PVs and LPVs in BRCA1/2 genes are correlated to a high risk of developing breast cancer and/or ovarian cancer (Hereditary Breast and Ovarian Cancer syndrome, HBOC); additionally, in recent years, an increasing number of BRCA 1/2 variants have been identified and associated with pancreatic cancer. Epidemiologic studies have highlighted that inherited factors are involved in 10% to 20% of PCs, mainly through deleterious variants of BRCA2. The frequency of BRCA1/2 germline alterations fluctuates quite a lot among different ethnic groups, and the estimated rate of PVs/LPVs variants in Italian HBOC families is not very accurate, according to different reports. The aim of our study is to describe the prevalence of a BRCA2 PV observed in a selected cohort of HBOC patients and their relatives, whose common origin is the eastern coast of Emilia Romagna, a region of Italy. This study provides insight into the frequency of the variant detected in this area and provides evidence of an increased risk of pancreatic and breast cancer, useful for genetic counseling and surveillance programs.

Case Report: A BRCA2 Mutation Identified Through Next-Generation Sequencing in a Birt–Hogg–Dubè Syndrome Family

Birt–Hogg–Dubé syndrome (BHDS) is a rare autosomal dominant inherited disorder caused by a mutation in folliculin (FLCN) gene transmitted via germline autosomal dominant pattern. Patients with this syndrome have an increased susceptibility to renal cell carcinoma, lung cysts, spontaneous pneumothorax, and benign skin hamartomas, and its diagnosis is not easy and consequently underestimated. Several mutations have been identified in FLCN gene, among which the majority of alterations are frameshift (insertion/deletion), nonsense, or splice-site mutations that generally produce unfunctional truncated FLCN proteins. Our aim is to present a case of a BHDS family whose proband is a 56-year-old patient who has been experiencing multiple disorders, has an FLCN genetic mutation, and has also been identified to have a pathogenic variant in BRCA2 gene. Our further purpose is to emphasize the importance of the next-generation sequencing (NGS) approach to identify potential multiple germline mutations in complex and rare oncologic disorders, allowing strict and more targeted cancer screening programs.

Precision Medicine for BRCA/PALB2-Mutated Pancreatic Cancer and Emerging Strategies to Improve Therapeutic Responses to PARP Inhibition

Simple Summary

For the small subset of pancreatic ductal adenocarcinoma (PDAC) patients with loss-of-function mutations to BRCA1/2 or PALB2, both first-line and maintenance therapy differs significantly. These mutations confer a loss of double-strand break DNA homologous recombination (HR), substantially altering drug sensitivities. In this review, we discuss the current treatment guidelines for PDAC tumors deficient in HR, as well as newly emerging strategies to improve drug responses in this population. We also highlight additional patient populations in which these strategies may also be effective, and novel strategies aiming to confer similar drug sensitivity to tumors proficient in HR repair.

Abstract

Pancreatic cancer is projected to become the second leading cause of cancer-related death by 2030. As patients typically present with advanced disease and show poor responses to broad-spectrum chemotherapy, overall survival remains a dismal 10%. This underscores an urgent clinical need to identify new therapeutic approaches for PDAC patients. Precision medicine is now the standard of care for several difficult-to-treat cancer histologies. Such approaches involve the identification of a clinically actionable molecular feature, which is matched to an appropriate targeted therapy. Selective poly (ADP-ribose) polymerase (PARP) inhibitors such as Niraparib, Olaparib, Talazoparib, Rucaparib, and Veliparib are now approved for several cancers with loss of high-fidelity double-strand break homologous recombination (HR), namely those with deleterious mutations to BRCA1/2, PALB2, and other functionally related genes. Recent evidence suggests that the presence of such mutations in pancreatic ductal adenocarcinoma (PDAC), the most common and lethal pancreatic cancer histotype, significantly alters drug responses both with respect to first-line chemotherapy and maintenance therapy. In this review, we discuss the current treatment paradigm for PDAC tumors with confirmed deficits in double-strand break HR, as well as emerging strategies to both improve responses to PARP inhibition in HR-deficient PDAC and confer sensitivity to tumors proficient in HR repair.

Germline Variants in DNA Damage Repair Genes: An Emerging Role in the Era of Precision Medicine in Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma is a lethal disease that is projected to become the second most common cause of cancer deaths by 2030. The role of adjuvant therapy after surgical resection has been established by several clinical trials to prolong survival and improve outcomes. Multiagent chemotherapy seems to be the most promising approach to counteract early recurrence and improve survival; however, in the era of precision medicine, patient selection and individualized therapy seems to hold the key to desirable superior outcomes. Several cancer susceptibility genes have been proven to be associated with an increased risk of pancreatic cancer, both familial and sporadic cases. The role of genomic profiling for germline variants has been extensive and of limited clinical value, considering their low prevalence in pancreatic ductal adenocarcinoma (PDAC). However, an accumulating body of evidence from several studies in the past decade have successfully shown a recognizable value of germline variants in risk assessment and patient stratification. Recently, anti-PD-1 therapy (pembrolizumab) has been FDA-approved for use in solid malignancies with a Mismatch repair deficiency or high Microsatellite instability. Several trials have evaluated the role of poly (ADP-ribose) polymerase (PARP) inhibitors in patients harboring germline BRCA1/2 mutations. Finally, germline variants in DNA damage response genes and particularly deleterious ones have the potential to guide therapy after surgical resection and serve as biomarkers to predict survival. The dire need to address challenges for applying precision medicine in real-life clinical settings for PDAC patients lies in further characterizing the genetic and molecular processes through translational research.