Beyond BRCA1 and BRCA2: Deleterious Variants in DNA Repair Pathway Genes in Italian Families with Breast/Ovarian and Pancreatic Cancers

BRCA2, PALB2, RECQL4 Germline Pathogenic Variants, and Somatic TP53 Mutation in Triple Metachronous Malignancies: A Case Report and Literature Review

Background

Multiple primary cancer (MPC) refers to the presence of more than one cancer in an individual. Triple primary malignancies are uncommon.

Case

We report the case of a 50-year-old postmenopausal woman in our gynecology department, diagnosed with endometrial cancer, ovarian cancer, and unilateral breast cancer. She carried germline mutations in BRCA2, PALB2, and RECQL4, along with a somatic pathogenic variant in TP53. Endometrial cancer patients harboring germline pathogenic variants in BRCA2 exhibit a heightened risk of ovarian and breast cancer. BRCA2 is known to play a role in the development of ovarian and breast cancer, while PALB2 is identified as a gene associated with breast cancer susceptibility. RECQL4 has been linked to breast cancer, cervical cancer, and other tumors.

Conclusion

Genetic testing may be imperative for identifying MPC in endometrial cancer patients. For individuals with BRCA2 and other gene pathogenic variants, routine examination and monitoring of the endometrium, ovaries, breasts, and other sites prone to polygenic cancer are recommended.

PATHOLOGICAL SIGNIFICANCE OF CDH1/E-CADHERIN GERMLINE SEQUENCE VARIANTS IN BREAST CANCER PATIENTS

BACKGROUND

Germline alterations of the CDH1 (E-cadherin) tumor suppressor gene have been reported in several epithelial malignancies like hereditary diffuse gastric cancer and lobular breast cancer. E-cadherin plays a central role in proliferation, maintenance of cell-to-cell adhesion, polarity, and epithelial-mesenchymal transition of tissue cells. It is necessary to analyze the impact of the CDH1 germline sequence variants on protein and predict its clinical significance in breast cancer (BC) progression. The aim of the current study was to evaluate the impact and association of CDH1 gene potentially pathogenic variants/likely pathogenic variants (PVs/LPVs) with the initiation and progression of BC.

MATERIALS AND METHODS

In this study, the clinical data of 200 BC patients have been analyzed based on the type of BC, age, grade, stage, hormonal status, and risk factors. Blood samples from 50 healthy donors were used as a control. Furthermore, CDH1 gene molecular analysis, along with in silico analysis, was provided to assess the invasiveness and progression of BC caused by the E-cadherin protein.

RESULTS

Four variants were identified by genetic screening within the CDH1 gene that included variations in exons 7, 8, 10, 11, and 13. Exon 10 had splice site mutation at position c.1337C>A, affecting the protein structure. In exon 11, there was an insertion of T base at position 1669, resulting in truncated protein compared to a normal one that can lead to the disease-causing non- sense-mediated decay and exon 13 variant c.2076T>C has already known polymorphism. In silico analysis of CDH1 showed the presence of the different variants that indicated the overall disruption of protein structure and function.

CONCLUSIONS

The further functional analysis of these variants and their association with BC can be ensured by increasing the sample size and in vivo studies using mouse models.

Role of PARP Inhibitors in Cancer Immunotherapy: Potential Friends to Immune Activating Molecules and Foes to Immune Checkpoints

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induce cytotoxic effects as single agents in tumors characterized by defective repair of DNA double-strand breaks deriving from BRCA1/2 mutations or other abnormalities in genes associated with homologous recombination. Preclinical studies have shown that PARPi-induced DNA damage may affect the tumor immune microenvironment and immune-mediated anti-tumor response through several mechanisms. In particular, increased DNA damage has been shown to induce the activation of type I interferon pathway and up-regulation of PD-L1 expression in cancer cells, which can both enhance sensitivity to Immune Checkpoint Inhibitors (ICIs). Despite the recent approval of ICIs for a number of advanced cancer types based on their ability to reinvigorate T-cell-mediated antitumor immune responses, a consistent percentage of treated patients fail to respond, strongly encouraging the identification of combination therapies to overcome resistance. In the present review, we analyzed both established and unexplored mechanisms that may be elicited by PARPi, supporting immune reactivation and their potential synergism with currently used ICIs. This analysis may indicate novel and possibly patient-specific immune features that might represent new pharmacological targets of PARPi, potentially leading to the identification of predictive biomarkers of response to their combination with ICIs.

Genetic and clinical characteristics of BRCA-associated hereditary breast cancer in the West region of Kazakhstan

Breast cancer is the most common cancer in women and is cause mortality in many countries. The purpose of this article is to determine the BRCA1 BRCA2 gene mutation polymorphisms, as well as to determine the clinical, histopathological and prognostic characteristics in patients with breast cancer in the western region of Kazakhstan. A study was conducted on the genotyping of 278 patients in the MC ZKMU Marat Ospanov with an established diagnosis of breast cancer, which revealed that out of 278 patients, of 3 cases were identified. In the age category up to 50 years, 70 cases were detected (25.1%) after 50 years 208 cases were identified (74%). Number of patients in stage I was 20 (7.1%) in stage second 204 (73%) and in stage third 54 (19%). By tumor size, 30(10%) cases were T1, 194 (69%) cases were T2, 35 (12.5%) cases were T3, and 19 cases were T4 (6.8%). According to metastasis of the lymph nodes, no lymph nodes were detected in 107 (38%) cases, 1-3 L/n (Lymph Nodes) in 95 (34%) cases, 4-9 L/n in 12 (4%) cases, 10 L/n in 4 (1.4%) cases and unknown cases was 60 (21%). In 99.6% of patients no distant metastases was detected. According to the molecular classification of the tumor, Luminal type A is most found in this study 147 (52.8%), then Luminal type B 57 (20.5%), HER-2 positive 26 (9.3%) and Triple negative 48 (17.2%). By ethnicity the Kazakh race is 182 (65%) the Caucasian race was 96 (34%). Large population screening studies involving all BRCA1/2 polymorphisms are required to confirm the penetrance, frequency and significance of a wide range of variations of BRCA1/2 genes in the Kazakh population.

Genomic Breakpoints’ Characterization of a Large CHEK2 Duplication in an Italian Family with Hereditary Breast Cancer

CHEK2 (checkpoint kinase 2; MIM# 604373) is a tumor suppressor gene that encodes a serine threonine kinase involved in pathways such as DNA repair, cell cycle arrest, mitosis, and apoptosis. Pathogenic variants in CHEK2 contribute to a moderately increased risk of breast and other cancers. Several variant classes have been reported, either point mutations or large intragenic rearrangements. However, a significant portion of reported variants has an uncertain clinical significance. We report an intragenic CHEK2 duplication, ranging from intron 5 to intron 13, identified in an Italian family with hereditary breast cancer. Using long range PCR, with duplication-specific primers, we were able to ascertain the genomic breakpoint. We also performed a real-time PCR to assess a possible loss-of-function effect. The genomic characterization of large intragenic rearrangements in cancer susceptibility genes is important for the clinical management of the carriers and for a better classification of rare variants. The molecular definition of breakpoints allows for the prediction of the impact of the variant on transcripts and proteins, aiding in its characterization and clinical classification.