Detection of high-risk cervical intraepithelial neoplasia and cervical cancer by amplification of transcripts derived from integrated papillomavirus oncogenes

Abstract

Cervical cancer emerges from cervical intraepithelial neoplasia (CIN) induced by high-risk HPV (HR-HPV) infections. However, the vast majority of CIN lesions regresses spontaneously, and only a few lesions persist or progress to invasive carcinoma. On the basis of morphological criteria, it is not possible to differentiate high-grade lesions that will regress or persist from those that inevitably will progress to invasive cancers. In most cervical carcinomas, human papillomavirus (HPV) genomes are integrated into host cell chromosomes and transcribed into mRNAs encompassing viral and cellular sequences. In contrast, in early preneoplastic lesions, HPV genomes persist as episomes, and derived transcripts contain exclusively viral sequences. Thus, detection of HPV transcripts derived from integrated HPV genomes may specifically indicate both CIN lesions at high risk for progression as well as invasive cervical cancers. Here, we established a protocol for the amplification of papillomavirus oncogene transcripts (APOT) from cervical specimens that allows us to distinguish episome- from integrate-derived HPV mRNAs. Cervical swab and biopsy samples from 549 patients attending outpatient clinics for cervical dysplasia were screened for the presence of HPV DNA, and 155 samples that were positive for either HPV type 16 (n = 143) or 18 (n = 12) were subjected to the APOT assay. In samples derived from normal cervical epithelia (n = 19) or low-grade cervical lesions (CIN I, n = 10), no integrate-derived HPV transcripts were found. In contrast, in 1 (5%) of 22 samples derived from CIN II lesions, in 10 (16%) of 64 samples from patients with CIN III lesions, and in 35 (88%) of 40 samples from patients with cervical cancer, integrate-derived HPV transcripts were detected. Thus, detection of integrate-derived HPV transcripts in cervical swabs or biopsy specimens by the APOT assay points to advanced dysplasia or invasive cervical cancer.