Cárcano F M, Lengert A H, Vidal D O, Scapulatempo Neto C, Queiroz L, Marques H, Baltazar F, Berardinelli G N, Martinelli C M S, da Silva E C A, Reis R M, Lopes L F
Department of Medical Oncology, Barretos Cancer Hospital, Barretos, Brazil.
Barretos School of Health Sciences, Dr. Paulo Prata - FACISB, Barretos, Brazil.
Andrology. 2016 Sep;4(5):866-72. doi: 10.1111/andr.12200. Epub 2016 May 6.
Testicular germ cell tumors (TGCT) are the most common malignant neoplasm in young men. DNA mismatch repair deficiency can lead to microsatellite instability (MSI), an important mechanism of genetic instability. A mutation of the BRAF gene has been implicated in the pathogenesis of several solid tumors and has recently become an important therapeutic target. The role of MSI and BRAF gene mutation in TGCT, particularly in refractory disease, is poorly understood and reported findings are controversial. In this study, we aimed to determine the frequency and clinical impact of MSI status and BRAF mutations in TGCT. DNA was isolated from formalin-fixed paraffin embedded (FFPE) tissue from 150 TGCT cases. The MSI phenotype was evaluated using multiplex PCR for five quasimonomorphic mononucleotide repeat markers. Exon 15 of the BRAF oncogene (V600E) was analyzed by PCR, followed by direct sequencing. Sixteen percent of cases were considered to have refractory disease. In a small subset of cases (17 for MSI and 18 for BRAF), the quantity and quality of DNA recovery were poor and therefore, were unable to be analyzed. The remaining 133 TGCT cases showed a complete absence of MSI. Of the 132 cases successfully evaluated for BRAF mutations, all were V600E wild-type. In conclusion, despite a distinct response of testicular germ cell tumors to therapy, microsatellite instability, and the BRAF V600E mutation were absent in all testicular germ cell tumors tested in this study.
睾丸生殖细胞肿瘤（TGCT）是年轻男性中最常见的恶性肿瘤。DNA错配修复缺陷可导致微卫星不稳定性（MSI），这是遗传不稳定的重要机制。BRAF基因突变与几种实体瘤的发病机制有关，最近已成为一个重要的治疗靶点。MSI和BRAF基因突变在TGCT中的作用，尤其是在难治性疾病中的作用，目前了解甚少，且报道的结果存在争议。在本研究中，我们旨在确定TGCT中MSI状态和BRAF突变的频率及其临床影响。从150例TGCT病例的福尔马林固定石蜡包埋（FFPE）组织中提取DNA。使用多重PCR对五个准单态单核苷酸重复标记评估MSI表型。通过PCR分析BRAF癌基因（V600E）的第15外显子，随后进行直接测序。16%的病例被认为患有难治性疾病。在一小部分病例中（17例用于MSI检测，18例用于BRAF检测），DNA回收的数量和质量较差，因此无法进行分析。其余133例TGCT病例均显示完全不存在MSI。在成功评估BRAF突变的132例病例中，所有病例均为V600E野生型。总之，尽管睾丸生殖细胞肿瘤对治疗有明显反应，但在本研究检测的所有睾丸生殖细胞肿瘤中均未发现微卫星不稳定性和BRAF V600E突变。
