Correlation of gene mutations and microsatellite instability in colorectal cancer tissues with clinicopathological features of patients / 肿瘤研究与临床

ABSTRACT

Objective:To explore KRAS, NRAS, BRAF gene mutations and microsatellite instability(MSI) in colorectal cancer tissues as well as their correlation with the clinicopathological characteristics of patients.Methods:The clinicopathological data of 473 colorectal cancer patients in Shanxi Province Cancer Hospital from October 2020 to May 2021 were retrospectively analyzed. The mutation status of KRAS, NRAS and BRAF gene in the paraffin tissues were detected by using amplification refractory mutation system (ARMS) method. Polymerase chain reaction (PCR)-capillary electrophoresis was used to analyze MSI status, and the correlation of the clinicopathological characteristics of patients with gene mutations and MSI status was analyzed.Results:The mutation rates of KRAS, NRAS and BRAF were 45.03% (213/473), 2.96% (14/473) and 5.50% (26/473), respectively in 473 patients with colorectal cancer. No case harbored both 2 gene mutations was detected. The mutation rate of KRAS gene in well differentiated adenocarcinoma was higher than that in poorly differentiated adenocarcinoma [47.4% (175/369) vs. 36.5% (38/104), χ2 = 3.89, P = 0.049]. NRAS mutation rate in female was higher than that in male [5.0% (10/202) vs. 1.5% (4/271), χ2 = 4.86, P = 0.027], and the NRAS mutation rate in patients with tumor diameter ≤ 3 cm was higher than that in those with tumor diameter >3 cm [7.1% (7/98) vs. 1.9% (7/375), P = 0.013]. BRAF mutation rate of tumors located in colon was higher than that in rectum [11.7% (20/171) vs.2.0% (6/302), χ2 = 19.81, P < 0.001]; BRAF mutation rate in poorly differentiated tumor was higher than that in well differentiated tumor [10.6% (11/104) vs. 4.1% (15/369), χ2 = 6.62, P = 0.010]; BRAF mutation rate in patients with mucus was higher than that in those without mucus [10.9% (11/101) vs. 4.0% (15/372), χ2 = 7.19, P = 0.007]; BRAF mutation rate in patients with lymphatic metastasis was higher than that in patients without lymphatic metastasis [8.2% (15/182) vs.3.8% (11/291), χ2 = 4.29, P = 0.038]. The incidence of high frequency MSI (MSI-H) in 473 colorectal cancer tissues was 7.19% (34/473). The incidence of MSI-H in colon was higher than that in rectum [14.0% (24/171) vs. 3.3% (10/302), χ2 = 18.82, P < 0.001]; the incidence of MSI-H in patient with poor differentiated tumor was higher than that in those with well differentiated tumor [17.3% (18/104) vs. 4.3% (16/369), χ2 = 20.46, P < 0.001]; the incidence of MSI-H in patients with mucus was higher than that in those without mucus [11.9% (12/101) vs. 5.9% (22/372), χ2 = 4.24, P = 0.039]; and the incidence of MSI-H in patients without lymphatic metastasis was higher than that in patients with lymphatic metastasis [10.0% (29/291) vs. 2.7% (5/182), χ2 = 8.75, P = 0.003]. In addition, the incidence of MSI-H was on the rise in patients with BRAF mutation ( P < 0.001). Conclusions:KRAS, NRAS, BRAF gene mutations and MSI status are correlated with the clinicopathological characteristics of patients with colorectal cancer; there is a close relationship between MSI-H and BRAF mutation.