Invader human papillomavirus (HPV) type 16 and 18 assays as adjuncts to HPV screening of cervical papanicolaou smears with atypical squamous cells of undetermined significance

BACKGROUND:

High‐risk (HR) human papillomavirus (HPV) testing is standard practice for triaging women who have Papanicolaou (Pap) smears with atypical squamous cells of undetermined significance (ASC‐US), however, only 5% to 17% of these women have underlying cervical intraepithelial neoplasia 2 (CIN‐2)/CIN‐3. Recent reports have demonstrated that the presence of either HPV type 16 (HPV‐16) or HPV‐18 confers an elevated risk for CIN‐2/CIN‐3. The current study was designed to determine the prevalence of HPV‐16 and HPV‐18 in ASC‐US Pap smears and to determine whether further typing would enhance the risk stratification of patients for CIN‐2/CIN‐3.

METHODS:

One hundred seventy‐eight Pap smears with ASC‐US were screened retrospectively for HR HPV by using the proprietary Invader screening assay followed by typing for HPV‐16 and HPV‐18 by using Invader type‐specific probes on 100 of the samples. Clinical follow‐up results were correlated with HPV types.

RESULTS:

Fifty‐one percent of the ASC‐US samples were positive for HR HPV, the majority of which (70%) harbored non‐HPV‐16/HPV‐18 HR HPV types; 27% were associated with HPV‐16, whereas only 3% contained HPV‐18. The screening assay indicated that 46% of women who had Pap smears with ASC‐US were in need of further HPV‐16/HPV‐18 typing. Testing for HPV‐16 stratified women with ASC‐US into 3 groups: 1) 14% of women were positive for HPV‐16 and had a high risk (54%) of CIN‐2/CIN‐3 on follow‐up biopsy, 2) 35% of women were positive for non‐HPV‐16 HPV types and had an intermediate risk (9%), and 3) 51% of women were negative for HPV and had a negligible risk for CIN‐2/CIN‐3.

CONCLUSIONS:

The combined application of a proprietary screening assay and a type‐specific HPV‐16 assay demonstrated global potential for the development of tailored management protocols for women who have Pap smears with ASC‐US. Cancer 2009. © 2009 American Cancer Society.