CCND1 and colorectal cancer: Cyclin D1 overexpression was related markedly with poor OS in colorectal cancer patients treated by single surgery (HR: 0.77, 95% CI: 0.63–0.93, P = 0.006) and surgery as well as chemoradiation (HR: 0.63, 95% CI: 0.48–0.83, P = 0.001), without significant heterogeneity between studies.