Clinical evaluation of polymerase chain reaction reverse hybridization assay for detection and identification of human papillomavirus type 16 variants

Background: Isolates of HPV16 comprise six variants: European (Eu), Asian (As), Asian-American (AA), North American (NA), African-1 (AF1), and African-2 (AF2) with different carcinogenic potentials. Highly reliable automatable techniques for HPV variant genotyping would be helpful to confirm the role of variants in cervical cancer in large epidemiological studies.

Objective: To validate the performance of a novel assay for identification of HPV16 variants.

Study design: The test is a multiplex PCR amplifying four small fragments from the E6 open reading frame (ORF). Variants are identified in a reverse hybridization assay with variant specific probes. The novel assay was compared to sequence analysis of the E6 ORF in 68 clinical samples. In addition, HPV16 variant distribution was studied in 218 cervical samples from women with normal cytology, squamous cell carcinoma (SCC) and adenocarcinoma of countries in Africa, Asia and South-America.

Results: There was 95.6% agreement between the test and sequencing. Analysis of the clinical panel including 218 positive samples revealed worldwide distribution patterns of HPV16 variants. Finally, a threefold increased risk for SCC with grouped Eu and As variants in South-American countries as compared to controls was found, although the association was not statistically significant.

Conclusions: The novel assay is a reliable and simple technique, distribution patterns of HPV16 variants in different world regions and disease associations could be established and it may be useful in further epidemiological studies investigating the role of HPV16 variants in cervical carcinogenesis.