TP53 and rectal cancer: In light of the inconsistent results regarding p53 status and the response to neoadjuvant CCRT, a meta-analysis that included 1830 cases documented the wild-type form of p53 status (low expression of p53 protein and/or wild-type p53 gene) being associated with pathologic responses in rectal cancer patients who received neoadjuvant radiation-based therapy (good response: risk ratio [RR] = 1.30; 95% confidence intervals [CI] = 1.14–1.49; p < 0.001; complete response RR= 1.65; 95% CI = 1.19–2.30; p = 0.003; poor response RR= 0.85; 95% CI = 0.75–0.96; p = 0.007) [40].