p16 protein is upregulated in a stepwise fashion in colorectal adenoma and colorectal carcinoma

Abstract

Background/Aims:p16 is tumor suppressor gene acting as a cell cycle regulator. The present study was conducted to compare p16 expression in normal, dysplastic, and malignant colonic mucosae, and to explore its relation to clinicopathological variables and follow-up data in colorectal carcinoma (CRC).Patients and Methods:Tissue microarrays were performed from 25 normal colonic mucosae, 41 colonic adenomas, and 191 CRC, with corresponding 50 nodal metastases. Immunohistochemistry was performed using anti-p16 antibody, sections were scored, and statistical analysis was performed. K-ras mutation detection was also performed.Results:Immunoexpression of p16 was significantly higher in CRC than in adenomas (P = 0.033) and normal colonic mucosa (P = 0.005). There was no statistically significant difference between p16 expression in CRC and nodal metastasis. There was no significant association between p16 immunoexpression in CRC and all clinicopathological data and survival probability. K-ras mutations were detected in 34% of CRC. However, there was no correlation between K-ras status and p16 expression (P = 0.325).Conclusion:Absence of p16 expression is correlated to a benign course of CRC adenomas. p16 has a key role in CRC progression and can be used as a marker for colorectal adenoma. On the other hand, it has no role as a predictive and/or prognostic factor in CRC. Further extended studies are required to explore the role of p16 as indicator of premalignant lesions in the colon and to test its relation with CRC histological grade, as well as to test its value as a new therapeutic target.

Long Non-Coding RNA SH3PXD2A-AS1 Promotes Cell Progression Partly Through Epigenetic Silencing P57 and KLF2 in Colorectal Cancer

“…P15 and P16 have also been identified as tumor-suppressive proteins in CRC [49, 51]. In this study, we reported that overexpression of P57 and KLF2 can inhibit proliferative ability of CRC cells, and cause G1/G0 phase arrest.…”

“…We also reported that lncRNA HOXA-AS2 mediated CRC proliferation partly through inhibiting P21 and KLF2 expression [30]. In addition, the effects of P15 and P16 on CRC progression have been studied previously [49-51]. …”

Squamous metaplasia within a sigmoid adenoma. A rare feature

“…P16 is a tumor suppressor gene with function in cell cycle regulation. The abnormal function of this gene is thought to be among the earliest events involved in the progression of carcinogenesis [13][14][15][16][17].…”

Prognostic and clinicopathological value of p16 protein aberrant expression in colorectal cancer

“…Among the 41 studies, 9 studies with 1731 patients were performed to analyze the correlation between p16 protein expression and OS of CRC, and 20 studies with 755 controls and 1733 cases were included for the analysis of risk of CRC. [ 26 – 66 ] In addition, clinical information was extracted to analyze the association between p16 protein expression and clinicopathological features of CRC. These characteristics of eligible studies are presented in Tables 1 and 2 .…”