Expression of Plasma miRNA-221 in Colorectal Carcinoma Patients and its Diagnostic Significance in Comparison with p53 Expression.

BACKGROUND: Colorectal carcinoma development progresses through a sequence of normal mucosa-polyp-carcinoma. Early detection of premalignancy is crucial for improved outcomes. We evaluated the diagnostic performance of plasma miRNA-221 and its feasibility in discriminating premalignant from malignant neoplasms and correlating it with immunohistochemical p53 expression.

METHODS: A total of 109 plasma samples were collected (76 carcinoma, 14 premalignant, and 19 controls). MiRNA221 was quantified by qPCR for calculation of ∆Ct using RNU6B as endogenous control. p53 immunohistochemical staining was performed on corresponding tissue.

RESULTS: Plasma miRNA-221 and p53 in tissues were significantly overexpressed in the malignant group when compared with the premalignant and control groups. Plasma miRNA-221 was increased in late-stage tumors with nodal or distant metastasis. ROC curve construction for distinguishing between malignant and premalignant tumors revealed a cutoff value of 2.97 with 74% sensitivity, 79% specificity, 73.7% positive predictive value and 78.6% negative predictive value (AUC = 0.824; p = 0.001). Plasma miRNA-221 significantly correlated with p53 in cancer samples (r = 0.507).

CONCLUSIONS: MiRNA-221 could have a diagnostic role in differentiating malignant from premalignant neoplasms and could also serve as a predictive marker indicating tumor progression.