Distribution of high-risk HPV types in Yugoslav women with cervical neoplasia

The purpose of this study was to determine the frequency of high-risk types of human papillomavirus (HPV) infection, namely type 16, 18, 31 and 33, among Yugoslav women diagnosed with different grades of squamous intraepithelial lesion (SIL), as well as to investigate the relationship between HPV infection and age, parity, age at first intercourse, number of sexual partners and residence of the patients, all of which are considered risk-factors.

DNA was isolated from cervical swabs of 72 women using phenol/chloroform/isoamylalcohol extraction. Detection of HPV DNA in patients' genomic DNA was performed using the polymerase chain reaction (PCR) method with type-specific primer pairs, and amplification products were analyzed using 2% agarose and 10% polyacrylamide gel electrophoresis.

Thirty out of 72 (41.7%) patients with cervical intraepithelial neoplasia (CIN) were HPV-positive and 8 of them were double positives. HPV31 was the most frequent high-risk HPV type in this group of patients (13.9%). Eighty percent of the high-grade SIL (HSIL) patients were HPV-positive and 38.8% of the low-grade SIL (LSIL) patients were HPV-positive. Compared to HPV-negative women, the HPV-positive ones were younger, had started sexual activity earlier, and overall had more sexual partners.

Our study showed that oncogenic HPV types are responsible for the transition of LSIL to HSIL, and for its further progression to an invasive carcinoma of the cervix. Thus, HPV typing should become a widely used method for identifying women with increased risk for developing HSIL and invasive cervical cancer. We also concluded that sexual behavior is connected with the frequency of HPV infection. Henceforth, introduction of prophylactic measures could reduce the incidence of HPV infected women in our country.