Association of oral contraceptive use and human papillomaviruses in invasive cervical cancers.

197 cases of invasive cervical cancer were biopsied and tested for presence of human papilloma virus (HPV) DNA and virus-positive and - negative cases were compared as to oral contraceptive use and other risk factors. These cases were all histologically confirmed invasive cervical cancers seen in the Panamanian National Oncology Institute ascertained from July 1985-June 1987. HPV DNA was identified by Southern or dot-blot hybridization using probes for HPV-16 -18 and - 33. 61% of the cases were considered positive for at least 1 of the tests. Women reporting oral contraceptive use within the last year or long-term (>44 years) use were 2.3 and 2.9-fold more likely to he HPV- positive than were non-users. Increased risk of HPV was also associated with urban residence and some rather than no formal education. Smoking was negatively associated with HPV. A non-significant trend was evident for multiple sexual partners of the women or for monogamous women of her partner. HPV was not linked with other cervical cancer risk factors such as age at 1st coitus parity or Pap screen history. The possibility of an interaction between HPV infection and oral contraceptive use in the genesis of cervical cancer or an increased expression of HPV genome in neoplasms of oral contraceptive users was discussed suggesting a multifactorial model of cervical cancer causation.