The expression of keratin 17 and p27 predicts clinical outcomes in colorectal cancer.

Keratin 17 (K17) is frequently overexpressed, associated with poor prognosis in various cancers, and contributes to p27 degradation during cancer progression. Using immunohistochemistry, we evaluated K17 and p27 expression and assessed their biological behavior and prognostic significance in 326 colorectal cancers. High K17 expression was associated with poorly differentiated tumors, high pT classification, and lymph node metastases. Low p27 expression was associated with large tumors, high pT classification, lymphovascular invasion, and lymph node metastases. The overall survival of patients with high K17 expression was significantly worse than that of patients with low K17 expression [hazard ratio (HR) = 1.805, 95% confidence interval (CI) 1.169-2.787; p = 0.007]. Patients with low p27 expression showed significantly worse overall survival than those with high p27 expression (HR = 3.082, 95% CI 1.722-5.517; p < 0.001). When combining the results of K17 and p27 expression, the K17^highp27^low expression group showed the worst overall survival. On the contrary, the K17^high/lowp27^high group showed the best overall survival (p < 0.001). Therefore, K17^highp27^low expression is an independent poor prognostic factor in colorectal cancer. Thus, high K17 and low p27 expression correlate with aggressive clinicopathologic behavior and can be used as poor prognostic markers in colorectal cancer.