RESUMO
Objective:To investigate the expression changes of farnesoid X receptor (FXR) in the evolution of normal intestinal mucosa, colorectal adenoma (CRA) and colorectal cancer (CRC), and the correlation of FXR expression with clinicopathological features and prognosis of patients with colorectal tumors.Methods:The UALCAN website tool was used to analyze the expression level of FXR gene transcripts of CRC and normal colorectal tissues in The Cancer Genome Atlas (TCGA) database. The patients undergoing colonoscopy and treatment in the Aerospace Center Hospital from January 2019 to September 2020 were selected, and the immunohistochemistry was used to detect the expression of FXR protein in 100 CRA tissues, 47 CRC tissues and 11 normal colonic mucosal tissues from healthy people (healthy control). Combining with clinical data, the relationship between FXR protein expression and clinicopathological characteristics of patients with colorectal tumors was analyzed. According to the Kaplan-Meier Plotter online database, the median expression level of FXR gene transcripts in CRC patients was analyzed, and the patients were divided into FXR low-expression group and high-expression group, the relationship between the expression of FXR gene and prognosis of CRC patients was investigated.Results:The analysis of data from TCGA database showed that the expression level of FXR gene transcripts in CRC tissues was lower than that in normal colorectal tissues ( P < 0.01). Immunohistochemical examination of the collected tissues showed that the positive rate of FXR protein gradually decreased from the cecum to the rectum. The positive rates of FXR protein in healthy control, CRA patients and CRC patients were 90.9% (10/11), 24.0% (24/100), 6.3% (3/47), and the difference was statistically significant ( χ2 = 35.56, P < 0.01); the positive rate of FXR protein in cancer tissues from CRC patients was lower than that in normal tissues adjacent to cancer [6.3% (3/47) vs. 65.2% (15/23)], and the difference was statistically significant ( χ2 = 27.98, P < 0.01). There was no statistical difference in the positive rate of FXR among CRA patients with different gender, age, maximum diameter of adenoma, and aggression (all P > 0.05). There was also no statistical difference in the positive rate of FXR among CRC patients with different gender, age, tumor site, maximum diameter of tumor, degree of differentiation, TNM staging, and vascular tumor thrombus (all P > 0.05). According to the survival analysis of Kaplan-Meier Plotter online database, the recurrence-free survival of CRC patients with high expression of FXR was better than that of patients with low expression of FXR ( P = 0.003). Conclusions:The expression level of FXR gradually decreases in the intestinal tissues of healthy people, CRA patients and CRC patients. The prognosis of CRC patients with low FXR expression is poor.