[2084] Role of Magnification in Visual Evaluation of Manual and Automated HPV In-Situ Hybridization in Oropharyngeal Carcinoma Biopsy Samples

Momin T Siddiqui, Cynthia Cohen, Nazneen Fatima. Emory University Hospital, Atlanta, GA

Background: Determination of Human papillomavirus (HPV) status has strong diagnostic, prognostic, and therapeutic implications in oropharyngeal cancers (OC). Determining the integration status of HPV by in situ hybridization (ISH) is cost effective and routinely utilized in clinical practice. However, the reliability of reporting is dependent on individual expertise and visual evaluation. In this study, we have compared the role of magnification in interpreting HPV ISH results of manual versus an automated method, using the Dako and the Enzo probe respectively.
Design: We evaluated 55 small biopsies of primary OC utilizing HPV ISH manual with the Dako probe and Leica Bond-III automation using the Enzo probe. Punctate dot-like nuclear positivity observed with low, intermediate or high magnifications, 10 x, 20 x or 40-60x, was assigned as 3+, 2+ and 1+ respectively. A single cell showing nuclear punctate dot-like staining was considered a positive result.
Results: Ten of 55 (18%) biopsies with manual HPV ISH and 30 of 55 (54%) biopsies with the automation method positive at 10x magnification, were considered 3+. Twenty two of 55 (40%) biopsies with manual HPV ISH and 6 of 55 (10%) biopsies with automation positive at 20x magnification, were 2+. Seven of 55 (12%) biopsies with manual HPV ISH and 14 of 55 (25%) biopsies with automation positive at 40-60x magnification, were considered 1+.

HPV ISH (Positive)10X (3+)20X (2+)40-60X (1+)
Manual10/55 (18%)22/55 (40%)7/55 (12%)
Automated30/55 (54%)6/55 (10%)14/55 (25%)

Conclusions: Magnification power plays a critical role in visual evaluation of HPV ISH. The dot like punctate staining may be very focal which requires careful visual determination of all tumor cells. Low magnification (10x) reveals positivity in 18% of cases with the manual method, whereas the automated technique, being more sensitive, reveals a high positivity rate (54%). Hence, automation provides a better and more efficient method for evaluating HPV ISH. Failure to evaluate under high magnification (40-60x) however, could give false negative results in 12% of cases with the manual method and 25% with automation. This could confound the analysis and effect therapeutic decisions.
Category: Techniques

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 298, Wednesday Morning


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