Correlation between the rs7101 and rs1063169 polymorphisms in the FOS noncoding region and susceptibility to and prognosis of colorectal cancer

Background: The FOS gene is located on human chromosome 14q21-31 and encodes the nuclear oncoprotein c-Fos. This study analyzed the correlation between the FOS noncoding region rs7101 and rs1063169 polymorphisms and colorectal cancer susceptibility and prognosis. Methods: We analyzed the FOS genotypes in 432 colorectal cancer patients and 315 healthy subjects by PCR/Sanger sequencing. Survival was analyzed by Kaplan-Meier and Cox regression analysis. Western blot was used to detect the expression of c-Fos protein in cancer tissues and adjacent tissues in colorectal cancer patients with different genotypes. Results: The presence of a T allele at rs7101 and a T allele at rs1063169 in FOS carried a higher risk of colorectal cancer [adjusted odds ratio (OR) = 1.237, 95% confidence interval (95% CI) = 1.131-1.346, P <=.001 and adjusted OR = 1.218, 95% CI = 1.111-1.327, P <= .001, respectively]. c-Fos protein levels were significantly higher in variant cancer tissues than in normal mucosa tissues (P<.05), and c-Fos proteins levels were also higher in homozygous variant cancer tissues than in heterozygous variant cancer tissues. The 3-year survival rate of patients with wild-type FOS was higher than that of patients with variant FOS (P<.05). Conclusion: The rs7101 and rs1063169 polymorphisms in the noncoding region of FOS are associated with the risk of developing colorectal cancer and the progression of colorectal cancer, which may be because the mutation enhances the expression of c-Fos protein to promote the incidence and development of colorectal cancer.