Experimental and epidemiological evidence suggests that CaCU is caused by persistent infection with high-risk HPV. Genotype 16 is the most commonly detected in CaCU. The E6 and E7 oncogenes largely explain the oncogenic potential of high-risk HPV. In the regulation of the expression of E6 it's important the viral protein E2 and LCR. Recently, several studies indicate that methylation of CpGs present in the LCR could have a potential role in the regulation of viral gene expression.