CDKN2A and hereditary clear cell renal cell carcinoma: Analysis of human renal cell carcinoma samples showed that the increased methylation levels of two specific CpG sites in Tensin3 gene promoter were correlated with lower Tensin3 gene expression [13]; Occupational exposure to polycyclic aromatic hydrocarbons induced hypermethylation of 22 specific CpG sites of p16INK4α and the correlation between hypermethylation and suppression of p16 were found in vitro [12].