Colorectal cancer (CRC) is one of the most common malignancies in the world. It's estimated about 1,8 M new CRC cases worldwide per year. A somatic mutation in the BRAF gene in the tumor is a negative prognostic factor. This work is aimed at studying the clinical and genetic characteristics of Russian CRC patients with the BRAF mutation. The BRAF mutations were studied by Sanger sequencing and digital droplet PCR in 489 patients and found in 34 (7%) cases. The most common mutation was p.V600E (82%). Also, rare variants were found: p.K601E, p.N581I, p.G596R, and p.D594N. All the patients with rare mutations were characterized by an unfavorable prognosis of the disease. The clinical features of the patients with BRAF mutations in the study include the predominant primary tumor site in the rectum, in addition to the right colon. Then, most of the cases were diagnosed in the advanced stages of the disease and were represented by high-grade adenocarcinomas. This article demonstrates the feasibility of analysis of the entire exon 15 of BRAF gene in CRC patients regardless of tumor localization.

中文翻译：

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俄罗斯 BRAF 突变结直肠癌患者的遗传和表型特征。

结直肠癌（CRC）是世界上最常见的恶性肿瘤之一。据估计，全球每年约有 180 万例新的 CRC 病例。肿瘤中 BRAF 基因的体细胞突变是预后不良因素。这项工作旨在研究具有 BRAF 突变的俄罗斯 CRC 患者的临床和遗传特征。通过 Sanger 测序和数字液滴 PCR 在 489 名患者中研究了 BRAF 突变，并在 34 例（7%）病例中发现。最常见的突变是 p.V600E (82%)。此外，还发现了罕见的变体：p.K601E、p.N581I、p.G596R 和 p.D594N。所有具有罕见突变的患者均以疾病预后不良为特征。研究中 BRAF 突变患者的临床特征包括直肠中的主要原发性肿瘤部位，以及右侧结肠。然后，大多数病例是在疾病的晚期诊断出来的，以高级别腺癌为代表。本文论证了在 CRC 患者中分析 BRAF 基因的整个外显子 15 的可行性，无论肿瘤定位如何。