Monica Marabelli

Hereditary breast and ovarian cancer (HBOC) syndrome accounts for 5–10% of all breast and ovarian cancers, with BRCA1 and BRCA2 pathogenic variants being the most common genetic alterations. However, additional genes such as BARD1, whose protein product interacts with BRCA1 via its N-terminal RING domain, have been implicated as low-penetrance contributors to cancer risk. This study aimed to investigate the frequency and distribution of the BARD1 variant c.1518_1519delinsCA (p.Val507Met) in a cohort of 920 patients undergoing genetic testing for hereditary cancer predisposition. Next Generation Sequencing (NGS) was performed using a 28-gene panel, and allelic frequencies of BARD1 were analyzed. Among 920 patients, 159 (17.28%) were pure heterozygous for the c.1518_1519delinsCA variant. Notably, c.1519G>A was never observed without c.1518T>C, suggesting a strong linkage between the two variants. The allele frequencies observed (34.51% for A at c.1519 and 77.88% for C at c.1518) challenge current reference genome expectations. Data from the ALFA database confirmed that these frequencies are consistent with population-level variation, not sample bias. Our findings raise the hypothesis that the reference allele at position c.1518 may not reflect the true wild-type sequence. While both c.1518T>C and c.1519G>A are individually classified as benign, their combined occurrence as a dinucleotide substitution (c.1518_1519delinsCA) warrants further investigation. These results underscore the importance of accurate variant annotation and population-specific frequency data for clinical interpretation of NGS findings. Although BARD1 remains a low-frequency contributor to HBOC compared to BRCA1/2, its inclusion in multigene panels is supported by the potential relevance of such complex variants.

Background and Aim: DNA methylation may contribute to a worsening in breast cancer (BC). Methods: We conducted a matched case–control study to investigate the contribution of DNA methylation (DNAm) in breast cancer recurrence risk. Genome-wide DNAm profiles were generated from peripheral white blood cells (WBC) collected post-surgery from women with primary breast cancer BRCA wild-type, using Illumina Infinium HumanMethylationEPIC array. Cases had to experience recurrence of breast cancer or death and were matched to controls (subjects without recurrence, ratio 1:2) by age at diagnosis (+/− 5 years) and follow-up duration. Results: We identified three differentially methylated regions between the groups. Cases showed two hypomethylated regions, one upstream of the vtRNA2–1 gene (estimate −0.30, p-value < 0.005), and one in the 5′ UTR region of the FGFR2 gene (estimate −0.34, p-value < 0.028), whereas one, upstream of the RUFY1 gene (estimate 0.32, p-value < 0.015), was hypermethylated. Additionally, we identified two methylation signals, recognised as predictors of biochemical traits. The chemokine ligand 21 (unadjusted p-value < 0.03) and insulin receptor expression (unadjusted p-value < 0.04) were higher in cases than in controls. Conclusions: Our exploratory study suggests that specific DNA methylation patterns in WBCs, particularly in genes related to cellular proliferation, invasion, and glucose homeostasis, may be associated with the risk of breast cancer recurrence in BRCA wild-type women. If validated in larger cohorts, these circulating signatures may serve as blood-based biomarkers to improve risk stratification and guide tailored treatment strategies.

Background/Objectives: Compared to single gene testing (SGT), multigene panel testing (MGPT) improves pathogenic variants (PVs) detection. However, MGPT yields complex results, including secondary findings, heterozygous PVs in recessive genes, low-penetrance PVs, and variants of uncertain significance. We reported our mono-institutional experience of germline testing in breast cancer (BC), comparing SGT and MGPT. Methods: We retrospectively analyzed clinical and molecular data from 1084 BC patients: 308 underwent SGT (BRCA1/BRCA2) and 776 MGPT (for 28 cancer-related genes). We compared these approaches regarding the genetic classification of the findings (positive, uncertain, uninformative) and their impact on clinical management (primary findings (PFs); complex and inconclusive results). Additionally, we described clinical features supporting one approach over the other and focused on copy number variation (CNV) frequency in non-BRCA genes. Results: We found ≥1 PV in 165 patients (165/1084 = 15.2%), including 91 in BRCA1/BRCA2 (91/1084 = 8.4%), with 42 identified by SGT (42/308 = 13.6%) and 49 by MGPT (49/776 = 6.3%). MGPT detected PVs in non-BRCA genes in 74 patients (74/776 = 9.5%), including 40 PFs. Overall, MGPT identified 89 PFs (89/776 = 11.5%). We observed complex results in 21 patients (21/308 = 6.8%) with SGT and in 300 (300/776 = 38.7%) with MGPT. Compared to MGPT, SGT detected a similar percentage of PFs (13.6% vs. 11.5%) but a significantly reduced percentage of complex results (6.8% vs. 38.7%) (p < 0.001). Triple-negative BCs prevailed in BRCA1 carriers, while ER-positive BCs were more prevalent in ATM/CHEK2 carriers. Concerning non-BRCA genes, MGPT detected CNVs in PALB2, representing 20% of PVs in this gene. Conclusions: Although MGPT increases hereditary BC detection, its complexity requires clear guidelines for optimal clinical management and strategies for merging the benefits of SGT and MGPT.

Women carrying pathogenic/likely pathogenic (P/LP) variants in moderate- or high-penetrance genes have an increased risk of developing breast cancer. However, most P/LP variants associated with breast cancer risk show incomplete penetrance. Age, gender, family history, polygenic risk, lifestyle, reproductive, hormonal, and environmental factors can affect the expressivity and penetrance of the disease. However, there are gaps in translating how individual genomic variation affects phenotypic presentation. The expansion of criteria for genetic testing and the increasing utilization of comprehensive genetic panels may enhance the identification of individuals carrying P/LP variants linked to hereditary breast cancer. Individualized risk assessment could facilitate the implementation of personalized risk-reduction strategies for these individuals. Preventive interventions encompass lifestyle modifications, chemoprevention, enhanced surveillance through breast imaging, and risk-reducing surgeries. This review addresses the current literature’s inconsistencies and limitations, particularly regarding risk factors and the intensity of preventive strategies for women with P/LP variants in moderate- and high-penetrance genes. In addition, it synthesizes the latest evidence on risk assessment and primary and secondary prevention in women at high risk of breast cancer.

Women carrying pathogenic/likely pathogenic (P/LP) variants in moderate- or high-penetrance genes have an increased risk of developing breast cancer. However, most P/LP variants associated with breast cancer risk show incomplete penetrance. Age, gender, family history, polygenic risk, lifestyle, reproductive, hormonal, and environmental factors can affect the expressivity and penetrance of the disease. However, there are gaps in translating how individual genomic variation affects phenotypic presentation. The expansion of criteria for genetic testing and the increasing utilization of comprehensive genetic panels may enhance the identification of individuals carrying P/LP variants linked to hereditary breast cancer. Individualized risk assessment could facilitate the implementation of personalized risk-reduction strategies for these individuals. Preventive interventions encompass lifestyle modifications, chemoprevention, enhanced surveillance through breast imaging, and risk-reducing surgeries. This review addresses the current literature's inconsistencies and limitations, particularly regarding risk factors and the intensity of preventive strategies for women with P/LP variants in moderate- and high-penetrance genes. In addition, it synthesizes the latest evidence on risk assessment and primary and secondary prevention in women at high risk of breast cancer.

According to the latest estimate from GLOBOCAN 2020, approximately 18

Metaplastic breast cancer (MpBC) is a rare, aggressive breast cancer (BC) histotype. Scarce information is available about MpBC genetic predisposition. Previous studies, mainly consisting of case reports, retrospective reviews and others on target therapies, pointed to a possible involvement of the BRCA1 gene in increasing MpBC risk, without ever confirming it. In this study, we retrospectively reviewed all BC patients counseled at our Institute for genetic testing of at least BRCA1 or BRCA2 (BRCA) genes and we found that 23 (23/5226 = 0.4%) were affected by MpBC. About 65% (15/23) of MpBC patients harbored a germline pathogenic variant (PV): 13 in BRCA1 (86.7%), including two patients who received genetic testing for known familial PV, one in TP53 (6.7%), and one in MLH1 (6.7%). We observed a statistically different frequency of MpBC in patients who carried a PV in the BRCA genes (13/1114 = 1.2%) vs. all other BC patients (10/4112 = 0.2%) (p = 0.0002). BRCA carriers proved to have an increased risk of developing MpBC compared to all other BC patients who were tested for BRCA genes (OR = 4.47; 95% CI: 1.95–10.23). Notably, MpBCs were diagnosed in 2.1% (13/610) of BRCA1 carriers. No MpBCs were observed in BRCA2 carriers (0/498 = 0%), revealing a statistically significant difference between the prevalence of MpBCs in BRCA1 and BRCA2 carriers (p = 0.0015). Our results confirmed that BRCA1 is involved in MpBC predisposition. Further studies on unselected patients are needed to elucidate the authentic role of BRCA1 and to explore the possible implication of other genes in MpBC predisposition.

Gastric cancer (GC) has long been a ‘Cinderella’ among hereditary cancers. Until recently, single-gene testing (SGT) was the only approach to identify high-risk individuals. With the spread of multigene panel testing (MGPT), a debate arose on the involvement of other genes, particularly those pertaining to homologous recombination (HR) repair. We report our mono-institutional experience in genetic counseling and SGT for 54 GC patients, with the detection of nine pathogenic variants (PVs) (9/54:16.7%). Seven out of fifty (14%) patients who underwent SGT for unknown mutations were carriers of a PV in CDH1 (n = 3), BRCA2 (n = 2), BRCA1 (n = 1), and MSH2 (n = 1), while one patient (2%) carried two variants of unknown significance (VUSs). CDH1 and MSH2 emerged as genes involved in early-onset diffuse and later-onset intestinal GCs, respectively. We additionally conducted MGPT on 37 patients, identifying five PVs (13.5%), including three (3/5:60%) in an HR gene (BRCA2, ATM, RAD51D) and at least one VUS in 13 patients (35.1%). Comparing PV carriers and non-carriers, we observed a statistically significant difference in PVs between patients with and without family history of GC (p-value: 0.045) or Lynch-related tumors (p-value: 0.036). Genetic counseling remains central to GC risk assessment. MGPT appeared advantageous in patients with unspecific phenotypes, although it led to challenging results.

Aims Analysis of microsatellite instability (MSI) is strongly recommended in endometrial cancer (EC) and colorectal cancer to screen for Lynch syndrome, to predict prognosis and to determine optimal treatment and follow-up. In a large monoinstitutional series of ECs, we evaluated the reliability and accuracy of Idylla assay, a rapid, fully automated system to detect MSI, and we compared its performance with two routine reference methods. Methods We evaluated MSI status in 174 formalin-fixed, paraffin-embedded EC tissue samples using immunohistochemistry (IHC) for mismatch repair (MMR) proteins and Idylla assay. Samples with discordant or equivocal results were analysed with a third technique, the Promega MSI kit. Results Idylla MSI assay and IHC were highly concordant (overall agreement: 154/170=90.59%, 95% CI 85.26% to 94.12%). However, in four samples, MMR-IHC staining was equivocal; moreover, 16 cases showed discordant results, that is, MMR deficient using IHC and microsatellite stable using Idylla. These 20 samples were reanalysed using the MSI-Promega kit, which showed the same results of Idylla assay in 18/20 cases (overall agreement: 90%, 95% CI 69.90% to 97.21%). Conclusions Our results suggest that IHC is an efficient method to determine MMR status in ECs. However, the Idylla MSI assay is a rapid and reliable tool to define MSI status, and it could represent a valuable alternative to conventional MSI-PCR methods.

There appears to be a sex-specific association between obesity and colorectal neoplasia in patients with Lynch Syndrome (LS). We meta-analyzed studies reporting on obesity and colorectal cancer (CRC) risk in LS patients to test whether obese subjects were at increased risk of cancer compared to those of normal weight. We explored also a possible sex-specific relationship between adiposity and CRC risk among patients with LS. The summary relative risk (SRR) and 95% confidence intervals (CI) were calculated through random effect models. We investigated the causes of between-study heterogeneity and assessed the presence of publication bias. We were able to retrieve suitable data from four independent studies. We found a twofold risk of CRC in obese men compared to nonobese men (SRR = 2.09; 95%CI: 1.23–3.55, I² = 33%), and no indication of publication bias (p = 0.13). No significantly increased risk due to obesity was found for women. A 49% increased CRC risk for obesity was found for subjects with an MLH1 mutation (SRR = 1.49; 95%CI: 1.11–1.99, I² = 0%). These results confirm the different effects of sex on obesity and CRC risk and also support the public measures to reduce overweight in people with LS, particularly for men.