GSTM1 and renal cell carcinoma: Patients ́ risk group was assessed by implementing the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) score, consisting of two clinical elements: less than 1 year between the time of diagnosis and systemic therapy and a Karnofsky performance status under 80% and four biological criteria as follows: Hb value below the lower limit of the normal range, neutrophil and platelet count exceeding the upper limit of the normal range and an elevated value of the corrected calcium (17).