In the investigators proposal, the investigators will examine at least 250 baseline liquid-based cytology specimens from women with normal cytology, low-grade squamous intraepithelial lesions (LSILs), high-grade squamous intraepithelial lesions (HSILs), microinvasions and invasive cervical cancers. Specimens will be tested for HPV DNA using HPV blot and type-specific PCR including type 16, 18, 52, 58, 31, 33, 39, 45, 51, 56, 59, 68, 6, and 11. Cervical specimens from women with HPV DNA types 16, 18, 52, 58, 31 and 33, which are the most prevalent oncogenic types in Taiwan, will be examined for physical status of viral DNA tested by real-time PCR and FISH, along with level of expression in mRNA.