Methylation level of the RASSF1A promoter is an independent prognostic factor for clear-cell renal cell carcinoma.

BACKGROUND: Ras association domain family 1A (RASSF1A) is a tumor suppressor that regulates the cell cycle, apoptosis, and microtubule stability. The association between the methylation levels of RASSF1A and the prognosis of clear-cell renal cell carcinoma (CCRCC) remains unclear. Therefore, we investigated this relationship to determine the prognostic value of RASSF1A methylation levels for CCRCC. PATIENTS AND METHODS: The study comprised 179 Japanese patients who underwent radical or partial nephrectomy for CCRCC. The methylation level of 5' CpG islands in the RASSF1A was evaluated using combined bisulfite restriction analysis and bisulfite sequencing. RESULTS: High levels of methylation in the RASSF1A promoter were significantly more frequent in grade 3 compared with grade 1 or 2 tumors (P = 0.028) and in patients with stage III or IV compared with patients with stage I or II (P = 0.043). Patients with high methylation levels had a significantly less favorable prognosis compared with those with low methylation levels (P = 0.040). Higher methylation levels were independently associated with a poor prognosis following multivariate analysis (P = 0.0053). CONCLUSION: These results indicate that quantitative promoter methylation levels of the RASSF1A gene may be a useful marker to predict the prognosis of CCRCC.

The association of DNA repair gene polymorphisms with the development and progression of renal cell carcinoma.

BACKGROUND: DNA repair enzymes repair some of the DNA damage associated with risk factors for renal cell carcinoma (RCC), including smoking. DNA repair gene polymorphisms modulate the repair capacity and might influence individual risk and progression of RCC. We examined associations between functional polymorphisms and risk, clinicopathologic characteristics and survival of RCC. PATIENTS AND METHODS: The study groups comprised 215 RCC patients and 215 age- and gender-matched healthy controls. Polymorphisms in xeroderma pigmentosum complementation groups C, D and G and X-ray repair cross-complementing groups 1 and 3 genes were genotyped. RESULTS: No significant differences in DNA repair genotype were observed between RCC cases and controls. In all patients, however, greater numbers (> or =3) of total variant alleles in all DNA repair genes studied were associated with less frequent venous extension (P = 0.0079). In smokers, some genotypes were associated with characteristics of RCC (Ps < or = 0.0067) and smokers with greater numbers of total variant alleles had improved overall survival (P = 0.040). CONCLUSION: These results suggest that DNA repair gene polymorphisms may not influence RCC susceptibility, but that some of them may influence RCC progression, especially in smokers, possibly due to altered DNA repair capacity by these polymorphisms.