Physical status of multiple human papillomavirus genotypes in flow-sorted cervical cancer cells

Multiple human papilloma virus (HPV) infections have been detected in cervical cancer. To investigate the significance of multiple HPV infections, we studied their prevalence in cancer samples from a low-risk (Dutch) and a high-risk (Surinamese) population and the correlation of HPV infection with tumor cell aneuploidy. SPF(10) LiPA was used for HPV detection in formalin-fixed cervical carcinoma samples from 96 Dutch and 95 Surinamese patients. Samples with HPV type 16 or 18 infections were sorted by flow cytometry, and fluorescence in situ hybridization was performed on the diploid and aneuploid subpopulations to detect HPV 16 and 18 genotypes simultaneously. Multiple HPV infections were present in 11 of 80 (13.8%) Dutch and 17 of 77 (22.1%) Surinamese carcinomas. Three cases had an HPV 16 and HPV 18 coinfection: in two cases, integrated HPV copies of HPV 16 or 18 were detected in the aneuploid fraction, and in one case both HPV 16 and 18 were present solely as episomes. Based on our findings, multiple HPV infections are present in cervical cancer samples from both high- and low-risk populations. Furthermore, multiple HPV types can be present in an episomal state in both diploid and aneuploid tumor cells, but integrated HPV genomes are detectable only in the aneuploid tumor cell subpopulations.