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

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.