P16(ink4a) Subcellular Expression Patterns in Colorectal Adenocarcinoma, Adenoma and Non-Neoplastic Tissue Samples

BACKGROUND: Colorectal cancer (CRC) is one of the most common neoplasms with high mortality at advanced stages worldwide. Thus diagnosis of CRC at an early stage with sensitive molecular methods is a high priority. The aim of this study was to evaluate P16(ink4a) subcellular expression patterns in colorectal adenocarcinoma, adenoma and non-neoplastic tissue samples. METHODS: A total of 137 colorectal formalin fixed paraffin-embedded tissue blocks from the pathology archives of Ali-Ebne-Abitaleb central hospital, Zahedan, Iran, were examined in three groups: adenocarcinoma (n= 63), adenoma (n= 38) and non-neoplastic (n= 36). The subcellular expression pattern was determined by immunocytochemistry. Data analysis was performed using Kruskal-Wallis and Fisher exact tests with the significance level set as p<0.05. RESULTS: P16(ink4a) subcellular localization was observed in three different patterns, nuclear+cytoplasmic (73.33%), cytoplasmic (13.33%) and nuclear (13.33%). In most samples, nuclear+cytoplasmic was the predominant subcellular pattern. However, a significant difference in P16(ink4a) subcellular expression patterns was observed along the non-neoplastic, adenoma, adenocarcinoma sequence (p<0.001). An association with the histological tumor type was also noted (p=0.021). CONCLUSION: Considering variation in localization of P16(ink4a) under different pathological conditions, P16(ink4a) night be sensitive prognostic biomarker for benign colon lesions. Its use may improve strategies for screening, prognostic assessment and management of patients with CRC. Further studies are recommended in this field.