However, in multivariate Cox analysis (including localization of the tumour, T classification, lymph node metastasis, pathological grade, and p21+/P-S6+ phenotype), we found that only the presence of regional lymph node metastasis at the time of diagnosis was a significant independent predictor of reduced disease-specific survival (Supplementary Table 4). This evidence concerns the gene RPS6 and metastatic malignant neoplasm in the lymph nodes.