PIK3CA和C-KIT基因突变与伴腋窝淋巴结转移乳腺癌临床病理特征及预后的关系

The relationship between the mutations of PIK3CA,C-KIT genes and clinicopathological characteristics,prognosis of breast cancer with axillary lymph node metastasis

目的探讨PIK3CA和C-KIT基因突变与乳腺癌伴腋窝淋巴结转移患者临床病理特征及预后的关系。方法收集84例乳腺癌伴淋巴结转移患者术后存档癌组织石蜡标本,采用Ion Torrent测序技术检测其PIK3CA、C-KIT基因的突变情况(突变率及突变位点分布);分析两种基因突变与临床病理特征(年龄、月经、淋巴结转移数、癌栓、肿瘤大小、临床分期、ER/PR和HER-2表达情况)的关系;根据突变情况分组(突变组和未突变组),随访3年无瘤生存率。结果 PIK3CA、C-KIT基因突变率分别为63.1%(53/84)和15.5%(13/84),均为错义突变;其中PIK3CA第9、13和20号外显子突变依次有7、8和24例,第13、20号外显子双突变共14例,而C-KIT基因突变均位于第10号外显子。两基因突变均与HER-2表达有关,仅PIK3CA与临床分期和ER/PR表达有关,但其各外显子突变与临床病理特征无关。PIK3CA基因突变组的3年无瘤生存率为75.5%,未突变组为48.4%;而C-KIT基因突变组与未突变组分别为76.9%和62.0%,两种基因不同突变情况的差异均无统计学意义(P>0.05)。年龄、月经、淋巴结转移数、肿瘤大小、临床分期、ER/PR表达、HER-2表达、PIK3CA基因突变和C-KIT基因突变均不是影响乳腺癌伴淋巴结转移患者预后的独立因素。结论乳腺癌伴腋窝淋巴结转移患者PIK3CA的基因突变率较高,与临床分期、ER/PR及HER-2表达有关;C-KIT仅与HER-2表达有关,两种基因突变可能在乳腺癌的发生发展及腋窝淋巴结转移中起一定作用。

Objective To explore the relationship between the mutation of P1K3CA, C-KIT genes and clinicopathological characteristics, prognosis of breast cancer with axillary lymph node metastasis. Methods The archival paraffin-embedded tissues from 84 cases of breast cancer with axillary lymph node metastasis were collected. The Ion Torrent sequencing technique was used to detect the mutation rates and distributions of PIK3CA and C-KIT genes. The relationship between the mutations of PIK3CA, C-KIT genes and clinicopathological characteristics （ age, menstruation, number of lymph node metastasis, tumor thrombus, tumor size, clinical stage, ER/PR and HER-2 expression） was investigated. The patients enrolled were divided into mutated group and non-mutated group and followed up for 3-year disease-free survival rate. Results All mutations were missense mutations with the rates of 63.1% （53/84） and 15.5% （13/84） for PIK3CA and C-KIT genes, respectively. Seven patients with PIK3CA mutation were in exon 9, 8 in exon 13, 24 in exon 20 and 14 in exons 13 and 20. All patients with C-KIT mutation were located in exon 10. Mutations in the two genes were relevant to HER-2 expression, while only the PIK3CA mutation were related to clinical stage and ER/PR expression. The 3-year disease-free survival rate was 75.5% in PIK3CA mutated group and 48.4% in PIK3CA non-mutated group or 76. 9% in C-KIT mutated group and 62.0% in C-KIT non-mutated group, without significant differences（P〉0. 05）. The factors （age, menstruation, number of lymph node metastasis, tumor size, clinical stage, ER./PR expression, HER-2 expression, PIK3CA mutations and C-KIT gene mutations） were not independent prognosis factors of breast cancer with lymph node metastasis. Conclusion The mutation rate of PIK3CA gene is high and relevant to clinical stage, ER/PR and HER-2 expression. Only the relevance to HER-2 expression is observed in C-KIT mutation. Mu-tations in both genes may play a certain role in the development of breast cancer and axillary lymph node metastasis.