Impact of sampling origin on molecular detection of high-risk human papillomavirus and oncogene expression

Abstract

Purpose of investigation: The recognition of high-risk human papillomavirus (HR-HPV) as an etiological agent of cervical cancer has increased the importance of testing for HPV, and this might contribute to better risk stratification.

Methods: Eighty-eight randomly selected cervical cancer specimens including biopsies and their respective smears were used in this study. Control scrapings were obtained from ten healthy women. The presence of HPV16 and HPV18 was investigated using the technique of polymerase chain reaction (PCR) with the specific primers for the L1 region, while mRNA expression of HPV16 E6-E7 was evaluated by a reverse transcription PCR method (RT-PCR).

Results: The positivity for the viral genotype was influenced by the quantity of amplified DNA used. In tumor biopsies the higher positivity for HPV16 (54.5%) and HPV18 (15.9%) was obtained using 687.4 ng of DNA. At smears level solely 31.8% of HPV16 was detected using an average DNA quantity of about 157.2 ng. The revelation of HPV types depends on clinicopathologic data; HPV16 was detected more in advanced stages of squamous carcinoma (SC) samples (20% stage I, 62% Stage II and 80% stage III), while HPV18 and double infection were found exclusively at advanced stages of SC and in adenocarcinoma (AC), respectively (60%, 40% stage III SC and 80%, 20% Stage II A and C). The prevalence of HPV16 E6-E7 transcripts was evaluated at tumor biopsy with frequencies of 50%.

Conclusion: Our data provide prospective evidence that HPV16/18L1 revelation at biopsy toward pathological types is efficient and correlates well with oncogenic transcript findings. Subtle changes in viral oncogene dynamics highlight the presence of other regulating proteins serving as additional biomarkers.