Abstract:

Objective To investigate the mutations of TP53 and KRAS genes in the patients with six common types of digestive system tumors， including colorectal cancer（COAD）， cholangiocarcinoma（CHOL）， gallbladder cancer（GBC）， liver hepatocellular carcinoma（LIHC），stomach adenocarcinoma（STAD）， and pancreatic adenocarcinoma（PAAD）， and to analyze the relationships between TP53 and KRAS gene mutations and clinical pathological characteristics， tumor mutation burden（TMB）， and microsatellite instability （MSI） of the patients. Methods The pathological paraffin or biopsy samples of 112 patients from January 2022 to December 2023 diagnosed with six types of tumors based on imaging and pathology were collected. Hybrid capture-based gene sequencing technology was used to detect TP53 and KRAS gene mutations in the patients with different types of tumors； mutation landscapes of common digestive system tumor samples were constructed. The patients were divided into high and low TMB groups according to the TMB levels. The mutation statuses of TP53 and KRAS genes in the patients with different types of digestive system tumors were compared， and the TP53 and KRAS gene mutations in the patients with different clinicopathological characteristics were examined. Results A total of 276 mutations were detected in the 112 samples， with the highest mutation rate in TP53 gene （67%），followed by KARS gene （34%）. TP53 gene mutation was most prominent in COAD， followed by LIHC， while KRAS gene mutation was most significant in PAAD. TP53 gene mutation mainly occurred in exons 5-8， while the KRAS gene mutation primarily occurred in exon 2. There was no statistically significant difference in TP53 gene mutation rate among the six types of digestive system tumors （P>0.05）， while the KRAS gene mutation rate showed statistically significant difference （P<0.05）. The mutation rates of TP53 and KRAS gene co-mutation also showed statistically significant difference among the six types of tumors （P<0.05）. There were statistically significant differences in TP53 and KRAS gene mutation rates between the patients with high TMB and low TMB （P<0.05）， while there were no statistically significant differences in TP53 and KRAS mutation rates between the patients with different sex， age， tumor size， differentiation degree， TNM stage， lymph node and/or distant metastasis and MSI （P>0.05）. Conclusion The mutation rates of TP53 and KRAS genes are higher in common digestive system tumors， which are related to tumor types and TMB.

Key words: Digestive system cancer, Gene mutation, TP53 gene, KRAS gene, Tumor mutation burden, Microsatellite instability