PREVALENCE OF HPV DNA IN CERVICAL LESIONS IN PATIENTS FROM ECUADOR AND JAPAN

Cervical cancer is about 6 times more frequent in Ecuador than in Japa n. We investigated the association between infection by the human papi llomavirus (HPV) and the genesis of cervical cancer in specimens of le sions of the cervical epithelium obtained from patients in Ecuador and Japan. We also examined the results of HPV DNA detection and typing b y the polymerase chain reaction (PCR) performed under the same technic al conditions in areas with differing rates of cervical cancer. Purifi ed tissue DNA from paraffin-embedded samples was amplified by PCR with universal and type-specific primers. HPV DNA was detected in 8 (20%) of 40 normal cervical epithelial samples from Ecuadorian patients, 19 (45%) of 42 low-grade squamous intraepithelial lesions (LSIL), 16 (50% ) of 32 high-grade squamous intraepithelial lesions (HSIL), and 38 (81 %) of 47 invasive squamous cell carcinomas (SCC) compared with 3 (10%) of 30 normal cervical specimens from Japanese patients, 107 (51%) of 210 HSILs, and 45 (71%) of 63 SCCs. The prevalence of HPV types 16 and 18 rose significantly with increasing histological grade (p<0.05). Th e prevalence of HPV DNA decreased with increasing age in both Ecuadori an and Japanese patients. The detection rate and type-specific distrib ution of HPV DNA were not correlated with geographic location. Finding s suggest that risk factors associated with poverty and underdevelopme nt may influence the prevalence of HPV infection and the sequence of e vents after HPV infection culminating in cervical cancer. These factor s may help to explain the differing geographic distribution of this di sease.