Distribution of human papillomavirus genotypes in cervical intraepithelial neoplasia and invasive cervical cancer in Canada

Infection with high-risk human papillomavirus (HPV) causes cervical intraepithelial neoplasia (CIN) and invasive cervical cancer (ICC). The distribution of HPV types in cervical diseases has been previously described in small studies for Canadian women. The prevalence of 36 HPV genotypes in 873 women with CIN and 252 women with ICC was assessed on cervical exfoliated cells analyzed with the Linear Array (Roche Molecular System). HPV16 was the most common genotype in CIN and ICC. The seven most frequent genotypes in order of decreasing frequency were HPV16, 51, 52, 31, 39, 18, and 56 in women with CIN1, HPV16, 52, 31, 18, 51, 39, and 33 in women with CIN2, HPV16, 31, 18, 52, 39, 33, and 58 in women with CIN3, and HPV16, 18, 45, 33, 31, 39, and 53 in women with ICC. HPV18 was detected more frequently in adenocarcinoma than squamous cell carcinoma (P = 0.013). Adjustment for multiple type infections resulted in a lower percentage attribution in CIN of HPV types other than 16 or 18. The proportion of samples containing at least one oncogenic type was greater in CIN2 (98.4%) or CIN3 (100%) than in CIN1 (80.1%; P < 0.001 for each comparison). Multiple type infections were demonstrated in 51 (20.2%) of 252 ICC in contrast to 146 (61.3%) of 238 women with CIN3 (P < 0.001). Adjusting for multiple HPV types, HPV16 accounted for 52.1% and HPV18 for 18.1% of ICCs, for a total of 70.2%. Current HPV vaccines should protect against HPV types responsible for 70% of ICCs in Canadian women.