Clinical utility of the imunohistochemical co-expression of p53 and MDM2 in thyroid follicular lesions

In order to investigate the possible correlation between p53 and MDM2 co-expression with clinicopathological features of differentiated thyroid cancer (DTC) and its use as diagnostic and/or prognostic markers, we used immunohistochemistry to evaluate 317 thyroid samples including 208 DTC and 94 benign nodules, in addition to 15 normal tissues. MDM2 and p53 expression were highly associated (r = 0.7161; p < 0.0001). The co-expression of p53-MDM2 was observed more frequently in malignant lesions (p < 0.0001) and helped characterize follicular patterned lesions distinguishing FVPTC from FA (p < 0.0001) and FVPTC from FTC (p < 0.0001). In addition, p53-MDM2 co-expression was associated with characteristics of less aggressiveness. It was more frequent in patients ≤45 years old (p = 0.0035), with unique tumors (p = 0.0095), tumors <2 cm (p < 0.0001), tumors without extrathyroid invasion (p = 0.0425), without metastasis at evolution (p = 0.0179), and in patients evolving free of disease after treatment (p = 0.0485). We suggest that p53-MDM2 co-expression profile analysis might help establishing diagnostic and determining prognostic of DTC patients.