Since downregulation of SOX17 protein expression is also seen in the transition of immature metaplasia into SIL, the methylation status of SOX17 was assessed in these squamous preneoplastic lesions, of which 12 out of 18 cases (66.7%) did not show methylation, while in 6 of the 18 (33.3%) LSIL/HSIL the promotor region was methylated, one case of LSIL and five cases of HSIL. The gene discussed is SOX17; the disease is squamous cell intraepithelial neoplasia.