Clinical Evaluation of ProExC on Liquid-Based Cervical Cytology Specimens and Its Correlation with p16INK4a and HC2 High-Risk Human Papillomavirus (hrHPV) Testing
R Jain, MA Pedigo, GL Rocco. Virginia Commonwealth University School of Medicine, Richmond, VA; BD Diagnostics, Burlington, NC
Background: The 2006 ASCCP consensus management guidelines recommend reflex hrHPV DNA testing for equivocal cytology (ASC-US) to increase the efficiency of cervical cancer screening by better risk stratification. This study was performed to evaluate a novel antibody cocktail (ProExC) in detecting hrHPV+ ASC-US cases and to compare its clinical usefulness with p16INK4a and HPV testing.
Design: Liquid-based cervical cytology (CC) specimens were collected using BD SurePath method and routine Pap staining was performed. The ASC-US cases reported over the past one month were triaged for hrHPV testing. Residual samples were used to prepare two additional slides for ProExC and p16INK4a immunocytochemical analysis. 16 additional CC samples received only for hrHPV DNA test were also included in this study. The slides were evaluated for presence of nuclear staining within cytologically abnormal epithelial cells. The sensitivity, specificity, PPV and NPV were calculated.
Results: The 52 slides stained with ProExC and p16 immunocytochemical stain (34 ASC-US, 13 NILM, 2 LSIL, 1 HSIL, positive and negative controls) were interpreted independently, and with no previous knowledge of the cytological diagnosis, by a pathologist1 and a cytotechnologist2, with 100% correlation to the reference results. Of these 50 cases, 14 cases were positive for ProExC, 9 for hrHPV and none for p16INK4a. 3/34 ASC-US and 2/13 NILM cases showed false positive staining with ProExC and were negative for hrHPV DNA. This false positive staining was due to positively stained reactive endocervical cells.
Table 1: Correlation between cytological diagnosis and hrHPV, ProExC and p16INK4a results.
|No. of cases||hrHPV+ cases||ProExC+ cases||p16INK4a+ cases|
Table 2: Correlation between hrHPV and ProExC results.
|hrHPV+ cases||hrHPV- cases||Total no. of cases|
|Total no. of cases||9||41||50|
The sensitivity and specificity of the ProExC test was 78% and 83%, and the PPV and NPV was 50% and 94% respectively.
Conclusions: Using hrHPV testing as a bench mark, a negative ProExC test result almost excludes the presence of hrHPV infection. Thus, ProExC is a useful and a better ancillary diagnostic test than p16INK4a in detecting hrHPV+ ASC-US cases and thus is helpful in identifying those cervical lesions that are most likely to progress.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 36, Wednesday Afternoon