Abstract: Objective To investigate the ultrasonographic features of primary liver cancer (PLC) patients with KRAS gene mutation, and investigate the correlation between KRAS gene mutation and lymph node metastasis.Methods A total of 168 patients with primary liver cancer admitted to our hospital from March 2018 to March 2021 were prospectively included as the research subjects. According to the occurrence of lymph node metastasis, they were divided into metastasis group (n=63) and non-metastasis group (n=105). Peripheral blood, cancer and para-cancer tissues were collected from the 2 groups, respectively. The KRAS gene mutation was detected by the KRAS/NRAS gene mutation combined detection kit. The KRAS protein expression levels in cancer and para-cancer tissues were detected by immunohistochemistry. Color Dopplar ultrasound was used to detect the imaging manifestations of liver tumors in 2 groups. To analyze the ultrasonic characteristics of primary liver cancer patients with KRAS gene mutation and the correlation between KRAS gene mutation and lymph node metastasis.Results (1) Among 168 patients with liver cancer, 36 patients with KRAS gene mutation. The KRAS gene mutation rate in patients with extrahepatic metastasis group was 57.14%(36/63), which was significantly higher than that in patients without extrahepatic metastasis group 0% (0/105). The difference was statistically significant (χ²=76.364, P<0.05). (2) Thirty-six patients with KRAS gene mutation were divided into KRAS low expression group and KRAS high expression group according to the expression level of KRAS protein. There was no significant difference of tumor size between the 2 groups (P>0.05). The expression level of KRAS protein in the patients with the number of tumor nodules ≥2, tumor capsule (-), blood flow grade III and vascular invasion (+) was significantly higher than that in the patients with the number of single tumor nodule, tumor capsule (+), blood vessel invasion (-), and blood flow grades I and II. The differences were statistically significant (χ²=8.333, 3.955, 10.823, 4.730, P<0.05). (3) The RI of the KRAS protein high expression group was significantly higher than that of the KRAS protein low expression group. The RI of the patient with the number of tumor nodules ≥2 was significantly higher than that with single tumor nodule, (t=18.725,21.897, P<0.05). (4) The results of Log stic binary regression analysis showed that the expression level of KRAS protein in liver cancer tissues was positively correlated with the number of tumor nodules, blood flow grade, vascular invasion, RI and other ultrasonic parameters. The higher the expression level of KRAS protein is, and negatively correlated with the capsule formation of the tumor.Conclusion KRAS gene mutation is more frequent in patients with primary liver cancer, especially in those combined with extrahepatic metastasis. KRAS gene mutation is closely related to the progression of liver cancer. KRAS gene expression level in liver cancer tissues combined with color Dopplar ultrasound imaging analysis can provide a reference value for clinical diagnosis and treatment for liver cancer.

Key words: Primary liver cancer, KRAS gene mutation, Ultrasonic characteristics, Lymph node metastasis, Correlation analysis