Prognostic value of programmed death ligand 1, p53, and Ki-67 in patients with advanced stage colorectal cancer

Abstract

Current prognostic indicators are ineffective for identifying advanced stage colorectal cancer (CRC) patients with high risk of recurrence after surgical resection. We investigated the prognostic value of p53, Ki-67, and programmed death ligand 1 (PD-L1) in 254 patients with stage II and III CRC. The expression of p53 was positive in 63% of cases. Up-regulation of p53 was associated with smaller tumor size (P = .001) and higher Ki-67 labeling index (LI) (P = .031). The tumor Ki-67 LI was high (≥ 20%) in 197 (78%) of the patients. High Ki-67 LI was associated with higher TNM stage (P = .031), positive p53 expression (P = .031), and negative PD-L1 expression (P = .003). The five-year relapse-free survivals (RFS) were 53% and 89%, respectively, for the p53-positive and Ki-67 LI-high patients and the p53-negative and Ki-67 LI-low patients (P < .001). In univariate analysis, negative p53 (P = .001), low Ki-67 LI (P = .006), low PD-L1 expression (P = .044), low TNM stage (P < .001), recto-sigmoid location (P = .026), and small size (P = .013) were significantly related to RFS. In multivariate Cox regression analysis, positive p53 expression (hazard ratio [HR]: 2.48; 95% confidence interval: 1.34–4.59, P = .004), high Ki-67 LI (HR: 2.62; 95% CI: 1.12–6.14, P = .027) and high TNM stage (HR: 2.598, 95% CI: 1.55–4.37, P < .001,) were independent predictors of unfavorable prognosis. In summary, PD-L1, Ki-67, and p53 staining individually had significant prognostic value for patients with stage II and III CRC. Moreover, combining p53 H-score ≥ 35 and Ki-67 LI ≥ 20% identifies patients with poor clinical outcome.