A Novel Technique for the Preparation of Formalin Fixed Paraffin Embedded Surgical and Cell Block Specimens, is Proven to be Effective for HPV Testing

Summary: Introduction: High-risk HPV testing is an important test for patients with a higher chance of HPV linked carcinoma. An effective method of deparaffinization is an important pre-analytic step that allows the BD Onclarity Assay to be used on formalin fixed paraffine embedded (FFPE) samples placed in SurePath Preservative fluid. Materials and Methods: The cohort of specimens in this study was obtained from previously tested specimens for high-risk HPV on the Roche cobas assay. 49 specimens underwent high-risk HPV extended genotype testing by the BD COR Onclarity system. An H&E slide was reviewed for tissue adequacy of 500 tumor cells (Figure 1). 10 unstained sections from surgical specimens and 20 unstained sections from FNA cell blocks were deparaffinized by placing the slides in a rack, soaking in a xylene bath at 30 minutes and then a second xylene bath at 15 minutes (Figure 2). Slides were then placed in 100% EtOH for 15 minutes and then a second 100% EtOH bath for 5 minutes. Slides were allowed to air dry. Once air dried, a hand scalpel was used to scrape the tumor cells directly into a SurePath vial with preservative fluid, vortexed and allowed to fix for 30 minutes. Using the BD Cor system, the Onclarity Assay for extended genotyping was performed (Figure 3). Results: Of 49 specimens tested, 25 (100%) specimens were high-risk HPV positive. 23 (96%) tested negative and 1 (4%) resulted as internal control failure (Table 1). Conclusions: FFPE samples prepared, using this novel method, resulted in 100% sensitivity and 100% specificity and with 100% accuracy in comparison to previous cobas testing. It is concluded that this method is an acceptable form of testing when using FFPE surgical and cell block tissue from suspected HPV mediated carcinoma with adequate tumor cells.