HPV16 E6*II gene expression in intraepithelial cervical lesions as an indicator of neoplastic grade: a pilot study.

Integration of the HPV genome into a host cell DNA leads to the deregulated overexpression of the viral E6 and E7 oncoproteins, and this is a key factor for progression from low-grade cervical lesions to high-grade lesions and invasive cervical cancer. The aim of our study was to analyze the expression levels of HPV E6I/E6II and E7 genes in cervical neoplasia of different grades. The analysis involved 10 low-grade squamous intraepithelial lesions (CIN1), 15 high-grade lesions (CIN2 and CIN3), as well as normal cytology samples (n=10). HPV genotyping was done using RealLine HPV 16/18 kit. The expression analysis was performed in real-time PCR assay using gene-specific primers and SYBR Green. HPV16 DNA was found in 65.71% patients, including also normal cytology samples. The increased expression level of E6I was observed in 12 (34.3%) patients. The expression of E6II was increased in 10 (28.6%) samples, and E7 overexpression was found in 14 (40%) patients. Significant positive correlation was observed between the amount of HPV16 DNA and the levels of E6I and E6II expression. There were no statistically significant differences in expression levels of the studied genes between the groups (CIN1 vs. CIN2/CIN3 vs. normal cytology). Statistically significant differences were found in CIN2/CIN3 group, with the higher expression of E6II as compared with E6I. We suggest that the expression level of E6*II gene might be used as an indicator of cervical cancer severity, in patients with high-grade cervical neoplasia, but these observations need to be confirmed in a larger patient cohort.