Identification of a novel in-frame deletion in BRCA2 and analysis of variants of BRCA1/2 in Italian patients affected with hereditary breast and ovarian cancer

Unlocking the potential of oncology biomarkers: advancements in clinical theranostics

INTRODUCTION

Cancer biomarkers have revolutionized the field of oncology by providing valuable insights into tumor changes and aiding in screening, diagnosis, prognosis, treatment prediction, and risk assessment. The emergence of "omic" technologies has enabled biomarkers to become reliable and accurate predictors of outcomes during cancer treatment.

CONTENT

In this review, we highlight the clinical utility of biomarkers in cancer identification and motivate researchers to establish a personalized/precision approach in oncology. By extending a multidisciplinary technology-based approach, biomarkers offer an alternative to traditional techniques, fulfilling the goal of cancer therapeutics to find a needle in a haystack.

SUMMARY AND OUTLOOK

We target different forms of cancer to establish a dynamic role of biomarkers in understanding the spectrum of malignancies and their biochemical and molecular characterization, emphasizing their prospective contribution to cancer screening. Biomarkers offer a promising avenue for the early detection of human cancers and the exploration of novel technologies to predict disease severity, facilitating maximum survival and minimum mortality rates. This review provides a comprehensive overview of the potential of biomarkers in oncology and highlights their prospects in advancing cancer diagnosis and treatment.

Increased Risk of Hereditary Prostate Cancer in Italian Families with Hereditary Breast and Ovarian Cancer Syndrome Harboring Mutations in BRCA and in Other Susceptibility Genes

Hereditary prostate cancer (HPCa) has the highest heritability of any cancer in men. Interestingly, it occurs in several hereditary syndromes, including breast and ovarian cancer (HBOC) and Lynch syndrome (LS). Several gene mutations related to these syndromes have been identified as biomarkers in HPCa. The goal of this study was to screen for germline mutations in susceptibility genes by using a multigene panel, and to subsequently correlate the results with clinical and laboratory parameters. This was undertaken in 180 HBOC families, which included 217 males with prostate cancer (PCa). Mutational analysis was further extended to 104 family members of mutated patients. Screening of HBOC families revealed that 30.5% harbored germline mutations in susceptibility genes, with 21.6% harboring pathogenic variants (PVs) and 8.9% having variants of uncertain significance (VUS). We found PVs at similar frequency in BRCA1 and BRCA2 genes (8.8% and 9.4%, respectively), while 0.56% of PVs were present in well-established susceptibility genes PALB2, TP53 and RAD51C. Moreover, 0.56% of monoallelic PVs were present in MUTYH, a gene whose function in tumorigenesis in the context of PCa is still unclear. Finally, we reported double heterozygosity (DH) in BRCA1/2 genes in a single family, and found double mutation (DM) present in BRCA2 in a separate family. There was no significant difference between the mean age of onset of PCa in HBOC families with or without germline mutations in susceptibility genes, while the mean survival was highest in mutated patients compared to wild type. Furthermore, PCa is the second most recurrent cancer in our cohort, resulting in 18% of cases in both mutated and non-mutated families. Our investigation shows that PVs were located mostly in the 3′ of BRCA1 and BRCA2 genes, and in BRCA2, most PVs fell in exon 11, suggesting a mutation cluster region relating to risk of HPCa. A total of 65 family members inherited the proband’s mutation; of these, 24 developed cancer, with 41 remaining unaffected.

Pancreatic Cancer with Mutation in BRCA1/2, MLH1, and APC Genes: Phenotype Correlation and Detection of a Novel Germline BRCA2 Mutation

Pancreatic ductal adenocarcinoma (PDAC) is the seventh leading cause of cancer death worldwide; most of cases are sporadic, however about 5% to 10% report a hereditary predisposition. Several hereditary syndromes have been associated with familial pancreatic cancer (FPC) onset, including hereditary breast and ovarian cancer syndrome (HBOC), Lynch syndrome (LS), Familial atypical multiple mole melanoma (FAMMM), Familial adenomatous polyposis (FAP), Li-Fraumeni syndrome (LFS), Peutz-Jeghers syndrome (PJS), and Hereditary pancreatitis (HP).The aim of this study was to determine the mutational status of a cohort of 56 HBOC families, 7 LS families, 3 FAP and FAMMM families, and 1 LFS family with at least one case of PDAC. Mutation analysis of BRCA1/2, ATM, CHEK2, PALB2, RAD51C, RAD51D, NBN, CDH1, TP53, MLH1, MSH2, MSH6, and PMS2 genes, showedmutation in BRCA1/2, MLH1, and APC genes. We founda high mutation rate in patients belong HBOC and LS families, with a percentage of 28.6% in both syndromes and prevalence in HBOC of BRCA2 mutations with one case of double mutation in BRCA2 gene. In FAP family, we found a pathogenic mutation in APC gene in 1/3 families. We observed an early onset of PDAC and a lower survival in PDAC patients belonging to mutated families, while no evidence of possible pancreatic cancer cluster regions was found. Moreover, we identified a novel BRCA2 germline mutation, c.5511delT (p.Phe1837LeufsX3), not reported in any database, that segregated with disease in HBOC patients. Mutational analysis was extended to family membersof mutated patients, both healthy and cancer affected, which revealed 23 unaffected family members that inherited the proband's mutation. Although correlative by its nature, the presence of a BRCA mutation in PDAC patients may have benefits in terms of optimized treatment and longer outcome.

Five Italian Families with Two Mutations in BRCA Genes

Double heterozygosity (DH) in BRCA1 and BRCA2 genes and double mutation (DM) in BRCA1 or BRCA2 are extremely rare events in the general population, and few cases have been reported worldwide so far. Here, we describe five probands, all women, with breast and/or ovarian cancer and their families. Particularly, we identified two probands with DH in the BRCA1/2 genes with a frequency of 0.3% and three probands with DM in the BRCA2 gene with a frequency of 0.5%. The DH BRCA1 c.547+2T>A (IVS8+2T>A)/BRCA2 c.2830A>T (p.Lys944Ter) and BRCA1 c.3752_3755GTCT (p.Ser1253fs)/BRCA2 c.425+2T>C (IVS4+2T>C) have not been described together so far. The DM in BRCA2, c.631G>A (p.Val211Ile) and c.7008-2A>T (IVS13-2A>T), found in three unrelated probands, was previously reported in further unrelated patients. Due to its peculiarity, it is likely that both pathogenic variants descend from a common ancestor and, therefore, are founder mutations. Interestingly, analyzing the tumor types occurring in DH and DM families, we observed ovarian cancer only in DH families, probably due to the presence in DH patients of BRCA1 pathogenic variants, which predispose one more to ovarian cancer onset. Furthermore, male breast cancer and pancreatic cancer ensued in families with DM but not with DH. These data confirm that BRCA2 pathogenic variants have greater penetrance to develop breast cancer in men and are associated with an increased risk of pancreatic cancer.

A novel PALB2 truncating mutation in an Italian family with male breast cancer

Male breast cancer (MBC) is a rare disease, accounting for ~1% of all breast cancer cases worldwide. Although other genes are also involved, predisposing genetic factors to MBC include germline mutations in the BRCA genes (BRCA2). Among the other genes, partner and localizer of BRCA2 (PALB2) is considered a moderate-penetrance breast cancer susceptibility gene that may also play a role in MBC predisposition. Thus, the aim of the present study was to determine the PALB2 gene status in 8 MBC cases selected from a cohort of 181 hereditary breast and/or ovarian cancer probands. We performed PALB2 mutational analysis by direct sequencing of 13 exons and adjacent intronic regions. This study showed the presence of a PALB2 truncating mutation in 1/8 (12.5%) cases. This novel mutation was named c.1285_1286delAinsTC (p.I429SfsX12) and is localized in exon 4 of PALB2, in the region encoding for the ChAM motif which is important for the efficient association of PALB2 to chromatin and for recruitment of the BRCA complex to accumulate RAD51 at double-strand break sites. Our findings indicate that PALB2 could be added to the list of breast cancer susceptibility genes also in families with MBC cases.

Laboratory medicine and medical oncology: the tale of two Cinderellas

Cancer represents a leading cause of death in the developed countries. The past 50 years have witnessed major progress in both laboratory medicine and clinical oncology that has translated into improved prognosis of cancer patients. From the humble beginnings as unrelated specialties, major advances in the understanding of molecular bases of cancer progression led to increased interactions between laboratory medicine and clinical (mostly medical) oncology. Laboratory medicine is now an integral part of the management of cancer patients. The many aspects of the role of laboratory medicine in clinical oncology include the determination of biomarkers that are used in establishing the diagnosis, predicting response to therapy or prognosis, study of the host response to tumor growth, detection of treatment toxicity and determining the concentrations of anticancer drugs.