Diagnostic importance of P16 in the differential diagnosis of well-differentiated liposarcoma and lipomas

Introduction: Because of pathological overlaps, distinguishing well-differentiated liposarcoma (WDL) from lipoma is difficult. Objectives: The purpose of this study was to evaluate P16 as a differentiating marker for WDL and lipomas Materials and Methods: This cross-sectional study was performed on 38 pathology samples of lipoma and WDL in the department of pathology of Al-Zahra hospital, affiliated with Isfahan university of medical sciences, from 2011 to 2018. The studied samples were examined by immunohistochemistry (IHC) to determine the presence of P16. Results: Evaluation of IHC data showed that all of the lipoma samples (100%) had a score of 0 for IHC staining. In comparison, 84.2% of liposarcoma samples had a score of 3, and this difference was statistically significant (P<0.001). Evaluating the sensitivity and specificity of P16 gene expression showed that this marker has 84% sensitivity and 100% specificity for diagnosing liposarcoma (95% CI: 0.6042-0.9661). Conclusion: The use of p16 to differentiate WDL from lipoma has a sensitivity of 84% and a specificity of 100%, which could be very helpful in pathological practice.