Kaiser Permanente Northern California (KPNC) routinely uses a FDA-approved pooled-HPV genotype DNA test for carcinogenic HPV (Hybrid Capture 2 [HC2], Qiagen Corporation, Gaithersburg, MD) as an adjunct to cytology for cervical cancer screening in women 30 and older and as a triage for immediate colposcopy for women with equivocal Pap results at all ages. We are teaming with KPNC to create a carcinogenic HPV-positive cohort (HPV Persistence and Progression Cohort or PaP Cohort) for investigating the natural history of HPV genotypes. Specifically, we will store approximately 60,000 baseline specimens from the following sub-populations: 1) approximately 40,000 HPV positives and a random population sample of 4,000 baseline specimens from women aged 30 years and older; 2) approximately 5,000 HPV-orcytology-positives and random population sample of 2,000 baseline specimens from women aged 25-29 years of age; and 3) approximately 5,000 HPV-or cytology-positives and random population sample of 2,000 baseline specimens from women aged 21-24 years of age. We will use efficient sampling designs to achieve high power with minimal laboratory analyses, with specimens selected for testing based on clinical outcomes ascertained by linkage to the Kaiser cytology and histology databases and KPNC s active yearly follow-up of all HC2-positive women. We plan to "follow" women for three years after their enrollment in 2007-8 by banking their residual specimens collected at their return visits; longer follow-up would likely be biased by extensive censoring due to treatment.