Prevalence of human papillomavirus in abnormal cervical smears in Malaysian patients

Cervical cancer is the second most common female malignancy in Malaysia. Despite advances in treatment, the overall survival for this disease has not changed in the last decade. Infection by certain types of HPV is recognized as a causal and necessary factor for its development. This study was carried out to determine the prevalence of HPV infection in abnormal cervical smears in Malaysian patients using archival cervical smears retrieved from the Cytopathology Unit, Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between the years 1992-1995. DNA was extracted from 38 abnormal smears comprising 25 intraepithelial lesions and 13 cervical carcinomas and 10 normal smears. Amplification of HPV genes was carried out using the polymerase chain reaction (PCR) technique. HPV genotypes were determined using direct sequencing and the results were compared to the database from Genebank. DNA was successfully extracted from all 48 cervical smears. High-risk HPV (HR-HPV) genotypes were detected in 95% of the abnormal smears. Eight high-risk oncogenic types were identified: 16, 18, 31, 51, 52, 56, 58 and 66. All (100%) cervical cancer smears showed presence of HR-HPV compared to 92% of the cervical intraepithelial lesions. Among the eight HR-HPV genotypes identified, HPV 16 and 52 were the commonest (23.7% each) HPV genotypes encountered and among the CIN lesions, HPV 16 (28%) was the most frequent. We conclude that HPV 16 is the most prevalent HPV genotype present in abnormal cervical smears in Malaysian patients, and that the use of archival material to assess the presence of HPV is potentially worthwhile, and can be utilized for longitudinal studies of HPV presence and persistence.