A hybrid-capture assay to detect HPV mRNA ratios in cervical specimens

Human papillomavirus (HPV) DNA screening benefits cervical cancer diagnosis, but a few HPV infections result in cancer. Assays that predict cancer are desirable. A potential biomarker is the ratio of HPV E6-7 over E2 transcripts, which may increase during early cancer progression. Modified hybrid-capture technology detected, in separate wells, HPV E6-7 or E2 mRNA of HPV 16 or HPV 18 in samples. The limit of detection was approximately 1000 copies of in vitro transcribed RNA with linear dynamic range approximately four logs. No cross-reactivity between HPV 16 and HPV 18 mRNAs was detected. RNA of SiHa cells was stable in clinical specimen pools for 67 days, as determined by RT-PCR. The ratio of HPV E6-7:E2 mRNAs was relatively high for cancer cells lines, SiHa, Caski and HeLa cells preserved in clinical specimen pools. A broad distribution of HPV 16 E6-7:E2 mRNA ratio was detected in a small set of clinical specimens with various histological diagnoses. Some specimen ratios were so high for cancer cell lines, but the significance of the results needs to be determined. This method may help determine the pattern of gene expression in HPV-related disease or in other systems.