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Introduction. The presence of a germinal BRCA mutation occurs in 3–4% of all breast cancer (BC) patients with various biological subtypes, but significantly with a high frequency in patients with a triple negative biological subtype (in 10–20% of cases). For the treatment of patients with HER2-negative metastatic breast cancer associated with gBRCA mutation, the effectiveness of biologically targeted drugs from the group of PARP inhibitors (olaparib and talazoparib) has been proven.Purpose. Comparison of the results of our experience with the use of talazoparib in patients with HER2-gBRCA+ + mBC with the data of the EMBRACA registration study.Materials and methods. As part of the multicenter compassionate use program (CUP) with the support of Pfizer, 24 patients with HER2-negative metastatic gBRCA-associated mutation metastatic breast cancer (HER2-gBRCA+ breast cancer) received biologically targeted therapy with the PARP inhibitor talazoparib at a standard oral dose of 1 mg per day for vital indications . The average age of patients with HER2-gBRCAm+ breast cancer was 50 years (29–90 years).Results. Objective response (OR) was registered in 29% of cases, disease control (OR+stabilization) – in 71% of cases. The median progression-free survival (PFS) was 6.5 months (95% CI [3–10]). Objective response, disease control, and median PFS were evaluated depending on the biological subtype, the number of lines of previous therapy, and the presence of platinum-containing agents in the anamnesis.Objective response and disease control were evaluated depending on the biological subtype: in patients with ER+HER2-mBC versus patients with triple negative subtype, OR was 33% vs 22%, and disease control was 83% vs 61%, respectively. In the presence of < 3 vs ≥ 3 lines of therapy for metastatic disease in the anamnesis, OR was 31% vs 12.5%, disease control – 75% vs 50% of cases, respectively. In the presence or absence of platinum-containing agents in the anamnesis, OR was observed in 22% vs 33% of cases, and disease control – 67% vs 67%, respectively.In patients with the luminal subtype versus patients with the triple negative subtype, the PFS was 9 months vs 5 months, respectively (HR = 0.705; 95% CI [0.231–2.147]; p = 0.5208). Median PFS in the presence of <3 vs ≥3 lines of therapy for metastatic disease in the anamnesis was 9 months vs 4 months, respectively (HR = 4,216; 95% CI [1,334–13,327]; p = 0.0056). In the presence or absence of platinum-containing agents in previous lines of therapy 5 months vs 9.5 months, respectively (HR =1.484; 95% CI [0.48–4.582]; p = 0.4750).During the treatment with talazoparib adverse events of the 3rd-4th grades were observed in 5 patients (20,8%). These include moderate and severe anemia in 3 patients (12.5%), thrombocytopenia in 1 patient (4%), and neutropenia in 1 patient (4%). The majority of patients (79,5%), which received talazoparib, did not require dose adjustment. The need to reduce the dose to 0.75 mg was noted in 3 patients (12.5%), to 0.5 mg – in 2 patients (8%). Hemotransfusion was performed in 3 patients. For effective therapy safety management regular monitoring of blood parameters is necessary.Conclusion. Thus, targeted therapy with talazoparib is an effective treatment option for HER2-gBRCA+ mBC.

We studied expression of Flt-1 and Flk-1 receptors on tumor cells obtained from 83 patients with locally advanced breast cancer after neoadjuvant chemotherapy. The mean period of observations was 32.3 months. The median recurrence-free survival periods for Flt-1(+) and Flt-1(-) patients were 55 and 32 months, respectively (p=0.0064). The overall survival periods for Flt-1(-) and Flt-1(+) patients were 45 and 67.6 months, respectively (p=0.014). The mean recurrence-free survival periods for Flk-1(+) and Flk-1(-) patients were 40.8 and 60.9 months, respectively (p=0.035). Expression of VEGF had no prognostic value. Our results show that overexpression of Flk-1 on breast cancer cells in patients receiving neoadjuvant chemotherapy is associated with a poor prognosis. By contrast, overexpression of Flt-1 improves survival.

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Background: Approximately 5–10% of all cancers are associated with hereditary cancer predisposition syndromes (HCPS). Early identification of HCPS is facilitated by widespread use of next-generation sequencing (NGS) and brings significant benefits to both the patient and their relatives. This study aims to evaluate the landscape of genetic variants in patients with personal and/or family history of cancer using NGS-based multigene panel testing. Materials and Methods: The study cohort included 1117 probands from Russia: 1060 (94.9%) patients with clinical signs of HCPS and 57 (5.1%) healthy individuals with family history of cancer. NGS analysis of 76 HCPS genes was performed using a custom Roche NimbleGen enrichment panel. Results: Pathogenic/likely pathogenic variants were identified in 378 of 1117 individuals (33.8%). The predominant number (59.8%) of genetic variants was identified in BRCA1/BRCA2 genes. CHEK2 was the second most commonly altered gene with a total of 28 (7.4%) variants, and 124 (32.8%) genetic variants were found in other 35 cancer-associated genes with variable penetrance. Conclusions: Multigene panel testing allows for a differential diagnosis and identification of high-risk group for oncological diseases. Our results demonstrate that inclusion of non-coding gene regions into HCPS gene panels is highly important for the identification of rare spliceogenic variants with high penetrance.