Analysis of the correlation between RBFOX1 gene copy number variation, mRNA and protein expression, and colorectal cancer

Abstract

Abstract Background: Copy number variation is a significant characteristic of colorectal cancer progression. RBFOX1 is the gene with the highest frequency of copy number loss in colorectal cancer, but current research related to it and colorectal cancer is relatively scarce. Methods: Data from TCGA and other sources were used to analyze the copy number variation and mRNA expression levels of RBFOX1, as well as their correlation with clinical pathological data. Immunohistochemistry and immunofluorescence experiments were used to analyze the expression of RBFOX1 protein in colorectal cancer cells and tissues. Results: RBFOX1 has a high frequency (22.4%) of copy number loss and diverse copy number variations in colorectal cancer tissues. High-level RBFOX1 deletion is prone to occur in the right-sided colon and tissues with high microsatellite instability. The copy number variation of RBFOX1 and mRNA expression are not correlated. In tumor tissues, RBFOX1 mRNA shows a characteristic of reduced expression, which is significantly related to BRAF mutation (P=4.7e-05, P=0.03). Low expression of RBFOX1 is prone to occur in the right-sided colon and tissues with high microsatellite instability. The protein encoded by RBFOX1 is expressed in normal intestinal tissues, but shows a characteristic of absence in some colorectal cancer tissues. Conclusion: In the right-sided colon and tissues with high microsatellite instability, RBFOX1 shows copy number loss and low mRNA expression. This characteristic is closely related to BRAF gene mutation, and the protein of RBFOX1 is absent in some colorectal cancer tissues.