PTEN, pAKT, and pmTOR Expression and Subcellular Distribution in Primary Renal Cell Carcinomas and Their Metastases

The present study evaluated pAKT, pmTOR, and PTEN expression in a tissue microarray of primary renal cell carcinomas (PRCCs), their metastases, and normal renal parenchyma (NRP) (N = 45) by means of immunohistochemistry. Metastases inmost subcellular compartments showed comparable and stronger expression for pAKT, pmTOR, and PTEN than PRCC and NRP, which was even more pronounced in patients with high-risk Memorial Sloan-Kettering Cancer Center (MSKCC) score. Furthermore, most subcellular compartments showed no differences between lymphogenous, haematogenous, synchronous, and metachronous metastases, which is interesting with regard to sensitivity to mTOR inhibitor therapy in metastasized RCCs with alterations in the PI3K/AKT pathway.