Study on early diagnostic system for cervical cancer with using liquid-based cytology samples

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1. Human papillomavirus (HPV) 16 DNA can be integrated into the DNA of cells, thereby disrupting E2 geneexpression, which leads to increased expression of the E6 and E7 viral oncogenes and progression to cancer. Liquid-based cytology samples were examined by quantitativereal-time polymerase chain reaction. The HPV 16 viral load per cell decreased from a low-grade squamous intraepithelial lesion (LSIL) to a cancerous lesion. The average HPV 16 DNA copy numbers for three different HPV 16 integration statuses were 64.1 for the episomal form, 465.5 for the mixed form, and 0.4 for the integrated form. Furthermore, the mean age of patients with the pure integrated form of HPV 16 was more than 10 years older than those of patients with the episomal and mixed forms. Quantitative real-timePCR appears to be a useful method for quantitative and physical status analyses of HPV in cervical cancer screening with LBC samples.2. HPV L1 capsid protein is expressed together with the productionof infectious viral particles, but its expression and relation to p16 expression, which has been a surrogate marker for HPV infection in cervix. Immunochemical analyses using antibodies against L1 capsid protein and p16 protein were carried out on LBC materials. L1 capsid protein was positive in 30% of LSILs and 12% of HSILs, butin 0% of SCCs. In contrast, p16 protein was positive in 55% of LSILs, 100% of HSILs, and 100% of SCCs. Expression of L1 capsid protein decreased with lesion progression from LSILs to HSILs and SCCs, whereas p16 protein was positive in all HSILs and SCCs. The correlation between Ll and p16 expressions suggests that L1(-)/p16(+) cases have the potential for progression, whereas L1(+)/p16(-) andL1 (-)/p16(-) cases may be nonprogressive lesions or potentially in remission.