Hereditary cancer predisposition syndromes are responsible for approximately 5–10% of all diagnosed cancer cases. In the past, single-gene analysis of specific high risk genes was used for the determination of the genetic cause of cancer heritability in certain families. The application of Next Generation Sequencing (NGS) technology has facilitated multigene panel analysis and is widely used in clinical practice, for the identification of individuals with cancer predisposing gene variants. The purpose of this study was to investigate the extent and nature of variants in genes implicated in hereditary cancer predisposition in individuals referred for testing in our laboratory. In total, 1197 individuals from Greece, Romania and Turkey were referred to our laboratory for genetic testing in the past 4 years. The majority of referrals included individuals with personal of family history of breast and/or ovarian cancer. The analysis of genes involved in hereditary cancer predisposition was performed using a NGS approach. Genomic DNA was enriched for targeted regions of 36 genes and sequencing was carried out using the Illumina NGS technology. The presence of large genomic rearrangements (LGRs) was investigated by computational analysis and Multiplex Ligation-dependent Probe Amplification (MLPA). A pathogenic variant was identified in 264 of 1197 individuals (22.1%) analyzed while a variant of uncertain significance (VUS) was identified in 34.8% of cases. Clinically significant variants were identified in 29 of the 36 genes analyzed. Concerning the mutation distribution among individuals with positive findings, 43.6% were located in the BRCA1/2 genes whereas 21.6, 19.9, and 15.0% in other high, moderate and low risk genes respectively. Notably, 25 of the 264 positive individuals (9.5%) carried clinically significant variants in two different genes and 6.1% had a LGR. In our cohort, analysis of all the genes in the panel allowed the identification of 4.3 and 8.1% additional pathogenic variants in other high or moderate/low risk genes, respectively, enabling personalized management decisions for these individuals and supporting the clinical significance of multigene panel analysis in hereditary cancer predisposition.

Background/Aim: A possible role of antibody-drug conjugates against tumors with low HER2-expression, leads to the emergence of a new “low-HER2” classification in breast cancer, encompassing tumors from the hormonal-receptor-positive and the triple-negative subgroups. There is a need for data (clinical trial data and real-world evidence) that will accurately describe this population, the risk of recurrence and the possible benefit of HER2 targeted therapies. Patients and Methods: We retrospectively analyzed 949 patients from our Department databases, with hormonal receptor-positive and HER2-negative early breast cancer, for whom detailed data for immunohistochemical HER2-staining could be retrieved. Results: HER2-low expression was detected in 66.6% of patients (472 IHC +1 and 160 IHC +2 and ISH-negative). Lobular, or mixed lobular and ductal cancers had a statistically significantly lower chance of being HER2-low when compared to pure infiltrative ductal carcinomas (53.1% vs. 69.3% respectively). HER2-low status was not prognostic for recurrence-free survival or response to neoadjuvant chemotherapy. There was a non-significant trend for increased risk of recurrence for HER2-low, compared to HER2-0, in patients with lobular or mixed lobular and ductal carcinomas (HR=2.192, 95% CI=0.819-5.912). Conclusion: Low expression of HER2 in hormonal receptor-positive early breast cancer does not affect prognosis but may lead to a shorter progression-free-survival in lobular and mixed ductal and lobular cancers. Despite optimal management, a large proportion of hormonal receptor-positive patients will relapse. Targeting HER2 in HER2-low cancers may offer a potential additional treatment strategy to improve survival of this group.

Background/Aim: Low expression of HER2 has defined a new “HER2-low” subgroup of breast cancer with distinct clinicopathological characteristics and both prognostic and predictive implications. The impact of low HER2 expression in metastatic hormone receptor-positive HER2-negative breast cancer treated with first-line CDK4/6 inhibitors has not been studied. Using real-world patient data, we aimed to identify prognostic differences in this patient population according to HER2 expression with immunohistochemistry. Patients and Methods: We retrospectively analyzed 191 patients from 5 Oncology Department databases in Thessaloniki, Greece, with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors in the first line, for whom detailed immunohistochemical HER2 data could be retrieved. Results: Median progression-free survival was numerically different among the different HER2 subgroups (3.35 years for HER2 0 tumors, 2.18 years for HER2 +1 tumors, 1.74 years for HER2 +2/ISH-negative tumors), but this difference was not statistically significant (p=0.477). Median PFS was statistically significantly longer in patients without visceral metastases (5.45 years) compared to patients with visceral metastases (1.61 years) (p=0.017). Median PFS was also statistically significantly longer in patients taking an aromatase inhibitor (2.99 years) compared to patients taking fulvestrant (1.33 years) (p<0.0001). There were no statistically significant differences in the other subgroups examined. Conclusion: CDK4/6 inhibitors are equally effective as first-line treatment agents, regardless of the exact level of HER2 expression. Numerical differences, however, do exist among the different HER2 subgroups, and merit further evaluation in future studies to better study this phenomenon.

Sunitinib is an oral, multitargeted tyrosine kinase inhibitor that has been approved for the treatment of metastatic renal cell carcinoma. Although the majority of sunitinib-treated patients receive a clinical benefit, almost a third of the patients will not respond. Currently there is no available marker that can predict for response in these patients.

Background: Hereditary cancer predisposition syndromes are responsible for approximately 5–10% of all diagnosed cancer cases. In order to identify individuals at risk in a cost-efficient manner, family members of individuals carrying pathogenic alterations are tested only for the specific variant that was identified in their carrier relative. The purpose of this study was to investigate the clinical use and implementation of cascade family testing (CFT) in families of breast cancer patients with pathogenic/likely pathogenic variants (PVs/LPVs) in cancer-related predisposition genes. Methods: Germline sequencing was carried out with NGS technology using a 52-gene panel, and cascade testing was performed by Sanger sequencing or MLPA. Results: In a cohort of 1785 breast cancer patients (families), 20.3% were found to have PVs/LPVs. Specifically, 52.2%, 25.1%, and 22.7% of patients had positive findings in high-, intermediate-, and low-penetrance breast cancer susceptibility genes, respectively. Although CFT was recommended to all families, only 117 families (32.3%) agreed to proceed with genetic testing. Among the first-degree relatives who underwent CFT, 70.3% were female, and 108 of 121 (89.3%) were cancer free. Additionally, 42.7%, 36.7%, and 20.6% were offspring, siblings, and parents of the subject, respectively. Our data suggest that CFT was mostly undertaken (104/117, 88.8%) in families with positive findings in high-risk genes. Conclusions: Cascade family testing can be a powerful tool for primary cancer prevention by identifying at-risk family members. It is of utmost importance to implement genetic counseling approaches leading to increased awareness and communication of genetic testing results.