HPV 16 E6 sequence variations in Indian patients with cervical neoplasia.

In a cross-sectional study performed between June 2001 and November 2003, the HPV 16 E6 gene of 50 women with cervical neoplasia and 20 cytologically normal women ('controls') was sequenced following amplification by PCR. The 350T to G variant was seen in 35 (70%) of 50 patients' isolates while it was seen in only 3 (15%) of the 20 isolates from the 'controls'. The higher occurrence of the 350G variant among the patients was statistically significant (P<0.01). Isolates from patients were grouped into the European (E), Asian-American (AA) and North-American (NA-1) phylogenetic clusters with 46 (92%) belonging to the E cluster. All the 20 isolates from 'controls' belonged to the E cluster. This study suggests an association of the HPV 16 350G variant with a higher risk of cervical neoplasia and a predominance of E lineage strains among Indian HPV 16 isolates.