S100A1 [S1/61]

S100A1 is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are involved in the regulation of a number of cellular processes, such as cell cycle progression and differentiation. S100A1 may function in stimulation of Ca2+-induced Ca2+ release, inhibition of microtubule assembly and inhibition of protein kinase C-mediated phosphorylation. In normal tissues, S100A1 is expressed in cardiac muscle, skeletal muscle and neuronal cells. Reduced expression of S100A1 has been implicated in cardiomyopathies. Recent studies have shown that S100A1 protein is present in renal oncocytomas and clear cell and papillary renal cell carcinomas, but not in chromophobe renal cell carcinomas. It is thus useful in distinguishing between these tumors. S100A1 was also found in 94% of nephrogenic adenoma, but negative in prostate carcinoma. It is a specific and sensitive marker for nephrogenic adenoma.