Expression of p16, p53, and Ki-67 in colorectal adenocarcinoma: A study of 356 surgically resected cases

Background/Aims: The aim of the present study was to investigate the clinicopathological significance of p53, Ki-67, and p16 expression in patients with colorectal adenocarcinoma. Methodology: We evaluated p53, Ki-67, and p16 expression in 356 patients with primary colorectal adenocarcinoma using an immunohistochemical staining method. The relationships between these protein expressions and clinicopathological factors were statistically analyzed. Results: Positive p53 staining was detected more often in typical adenocarcinoma compared to mucinous adenocarcinoma (49% versus 17%, p=0.007) and in well or moderately differentiated adenocarcinoma compared to poorly differentiated adenocarcinoma (50% versus 32%, p=0.030). The level of expression of p53 protein was related to lymph node metastasis (p<0.001) and the TNM stage of the colorectal adenocarcinoma (p=0.006). The p53 protein expression was related to an increased tendency of lymphovascular invasion (p=0.058). However, Ki-67 and p16 expression levels were not associated with any of the clinicopathological variables. The overexpression of p53 was correlated with a higher level of Ki-67 (p=0.001) and positive staining of p16 (p<0.001). Conclusions: Our data suggest that overexpression of p53, which was correlated with Ki-67 and p16 expression, plays a critical role in aggressive tumor behaviors in patients with colorectal adenocarcinoma. However, further long-term follow-up studies are warranted to evaluate the clinical impacts of p53 in a larger group of patients.