PLAGL1 (ZAC1/LOT1) Expression in Clear Cell Renal Cell Carcinoma: Correlations with Disease Progression and Unfavorable Prognosis

Background: Pleiomorphic adenoma gene-like 1 (PLAGL1) protein was originally shown to induce cell-cycle arrest and promote apoptosis in several types of human tumors and therefore it was considered a candidate tumor suppressor. The involvement of PLAGL1 gene in the etiology and pathogenesis of clear cell renal cell carcinoma (ccRCC) has not been evaluated. The purpose of the present study was to determine the expression level of PLAGL1 in ccRCC and to investigate its potential utility as a prognostic factor. Materials and Methods: We applied quantitative real-time polymerase chain reaction (QPCR), western blotting and immunohistochemistry to measure PLAGL1 mRNA/protein contents in paired tumor and kidney specimens of 40 patients with ccRCC. Results: PLAGL1 mRNA and protein levels were increased in tumor tissues as determined by QPCR and immunohistochemistry, respectively. The average content of PLAGL1 protein measured by western blotting did not differ between tumor and non-cancerous kidney tissues. However, increased PLAGL1 protein level in ccRCC tissue positively correlated with the presence of distant metastases and worse patient outcome. Conclusion: These results suggest an oncogenic role of PLAGL1 in the progression of ccRCC and its potential value as a prognostic marker.