p21 is a Prognostic Marker for Renal Cell Carcinoma: Implications for Novel Therapeutic Approaches

Purpose: Kidney cancer, although relatively rare compared to other malignancies, is the most lethal of the common urological malignancies. Current treatments are inadequate as evidenced by a poor 5-year survival of patients with metastatic disease. Since there exists a significant disparity in the survival of patients with localized vs metastatic disease, efforts are under way to identify molecular markers of progression as well as targets for novel therapeutic approaches. The apoptosis and cell cycle regulatory protein, p21waf1/cip1, has been investigated as a possible target in other cancers since it is involved in the repair and apoptotic response of normal and malignant cells to DNA damage.Materials and Methods: We performed immunohistochemical analysis of a tissue array of 366 patients for which we have data on grade, stage and survival. We found that nuclear p21 is most highly expressed in collecting duct carcinoma and lowest in oncocytoma. Cytosolic p21 staining was highest in oncocytoma.Results: I...