423例结直肠癌KRAS/NRAS/BRAF/PIK3CA基因突变与临床病理的关系分析

Mutations of KRAS/NRAS/BRAF/PIK3CA in 423 patients with colorectal cancer and their relationships with clinicopathological features

目的分析结直肠癌(colorectal cancer,CRC)肿瘤组织中KRAS/NRAS/BRAF/PIK3CA基因突变与临床病理的关系。方法选取2014年7月-2019年5月于解放军总医院第一医学中心行手术切除的423例原发性CRC患者肿瘤组织标本进行回顾性分析,采用扩增阻滞突变系统与Taqman探针相结合的方法检测KRAS/NRAS/BRAF/PIK3CA基因的体细胞突变热点,分析其与临床病理特征的关系。结果423例CRC中,4种基因(KRAS/NRAS/BRAF/PIK3CA)总突变率为58.87%(249/423),其中KRAS突变率为44.68%(189/423),NRAS突变率为4.73%(20/423),BRAF突变率为3.78%(16/423),PIK3CA突变率为5.67%(24/423)。此外还发现KRAS和PIK3CA共同突变率为3.07%(13/423);BRAF和PIK3CA共同突变率为0.95%(4/423)。KRAS基因在脉管内癌栓[OR:0.351,P=0.003]和淋巴结转移[OR:0.583,P=0.006]病例中突变率明显降低;NRAS基因在肿瘤高分化组(OR:5.984,P=0.026)中突变率明显升高。BRAF基因在右半结肠肿瘤中突变频率明显升高[OR:4.286,P=0.005]。KRAS、NRAS、BRAF和PIK3CA基因突变与性别、年龄、肿瘤大小、大体分型、神经侵犯、肝转移和临床分期等因素无关(P均>0.05)。结论本组结直肠癌患者中KRAS、NRAS、BRAF和PIK3CA这4个基因突变与大部分临床病理指标无关,但是KRAS突变较少出现在脉管内癌栓和淋巴结转移患者中,BRAF突变更多地出现在右半结肠。

Objective To investigate the relationship?between clinicopathological features and mutations of KRAS/NRAS/BRAF/PIK3CA in the tumor tissues of colorectal cancer(CRC).Methods A total of 423 primary CRCs tissue specimens were collected from the first medical center of Chinese PLA General Hospital from July 2014 to May 2019.The hotspot somatic mutations of KRAS/NRAS/BRAF/PIK3CA were detected by amplification-refractory mutation system-polymerase chain reaction(ARMS-PCR)and Taqman probe.The relationships between each gene mutation and clinicopathological features were analyzed.Results Totally 249(58.87%)patients had at least one mutation in the tested genes(KRAS/NRAS/BRAF/PIK3CA).The mutations of KRAS,NRAS,BRAF and PIK3CA were detected in 189(44.68%),20(4.73%),16(3.78%)and 24(5.67%)cases,respectively.In addition,13(3.07%)patients harbored co-mutation of KRAS and PIK3CA,and 4(0.95%)patients harbored co-mutation of BRAF and PIK3CA.KRAS gene mutation was less observed in patients with cancer suppository(OR,0.351;P=0.003)and lymph node metastasis(OR,0.583;P=0.006).The NRAS gene mutation was more frequent in well-differentiated CRC specimen(OR,5.984;P=0.026);The frequency of the BRAF gene mutation in the right half of the colon was significantly higher than that in the left half colon(OR,4.286;P=0.005).These gene mutations were not significantly associated with gender,age,tumor size,gross classification,nerve invasion,liver metastasis,and clinical staging(all P>0.05).Conclusion The mutations of KRAS,NRAS,BRAF and PIK3CA in CRCs has no significant relationship with most clinicopathological features.However,mutant KRAS may be less likely associated with the intravascular cancer suppository and lymph node metastasis,mutant NRAS is associated with tumor differenation,and mutant BRAF is more frequent in right side of the colon in CRC.