Distribution of HPV-16 variants among isolates from Paraguayan women with different grades of cervical lesion

Abstract

Objective: To determine the distribution of HPV-16 variants among Paraguayan women with different grades of cervical lesions.

Methods: Sixty-seven HPV-16-positive cervical samples obtained from women attending health centers in Paraguay between March 2007 and April 2009 were examined, including 29 low-grade squamous intraepithelial lesion (LSIL), 29 high-grade squamous intraepithelial lesion (HSIL), 4 cervical cancer, and 5 normal cytology samples. The specimens were analyzed by PCR-directed sequencing of a 364-bp fragment of the long control region of HPV-16, and a phylogenetic tree was compiled with MEGA 5.0 software.

Results: Most HPV-16 variants belonged to the European branch (82%); these variants were detected among 25 of 29 women with LSIL, 22 of 29 women with HSIL, 3 of 4 women with cervical cancer, and all women with normal cytology. Two isolates yielded new variants of the European branch with nucleotide substitutions at positions A7752C and A7810T. Non-European variants, such as African type 1 (1.5%) and Asian-American (16.5%), were detected only among women with cervical lesions (4/29, LSIL; 6/29, HSIL; 1/29, cervical cancer). These variants had at least 6 nucleotide substitutions adjacent to or within transcription factor binding sites.

Conclusion: All branches of HPV-16 variants were detected among Paraguayan women with cervical lesions.