Intracellular Chloride Ion Channel Protein-1 Expression in Clear Cell Renal Cell Carcinoma.

Abstract

Chloride intracellular channel 1 (CLIC1) represents a promising target for personalized therapy. Our aim was to assess CLIC1 expression in clear cell renal cell carcinoma (cc RCC) and identify its possible prognostic role. Fifty cases of cc RCC were evaluated and selected for immunohistochemistry. CLIC1 expression was correlated with tumor grade, invasion and heterogeneity. A total of 87.5% of the cases were CLIC1 positive, with either a homogeneous (31.42%) or a heterogeneous (68.57%) pattern. Low, mild and strong CLIC1 expressing tumors were defined based on nuclear (N), cytoplasmic (C), membrane (M) or combinations of them (NC, NM, CM, NCM) in terms of CLIC1 distribution. A significant correlation was found between tumor grade and percent of positive tumor cells (p=0.017). For G3 tumors, CLIC1 cytoplasmic expression was strongly correlated with high expression status (p=0.025) and tumor heterogeneity (p=0.004). CLIC1 expression was also correlated with metastasis (p=0.046). We defined four cc RCC groups depending on G, CLIC1 expression and pattern: i) G3/NM/low CLIC1+, ii) G2/CM/mild CLIC1+ iii) G1 or G2/NM or CM /high CLIC1+, and iv) G2/M /high CLIC1.