Finally, using Kaplan–Meier analysis of DFS to compare RAD50 low and high expression groups with tumors classified by perineural invasion status, we found that low levels of RAD50 expression in rectal cancer tissues were significantly associated with perineural invasion (Figure 2C,D), indicating that low RAD50 in the context of PNI (perineural invasion) is a marker of poor prognosis. This evidence concerns the gene RAD50 and rectal cancer.