A statistically significant association between methylation and histologic type was observed, where MLH1 methylation had a higher frequency in SCC (45.6%) and LCC (40.7%) compared with ADC (22.8%); RASSF1A methylation was associated with LCC (53.7%); BLU and RARβ methylation with ADC (45.7% and 60.9%). The gene discussed is RARB; the disease is AIDS dementia complex.