Prediction of high-grade anal intraepithelial neoplasia using DNA methylation measurements – preliminary data
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Abstract. Background: New and better methods are needed to improve diagnosis of high-grade anal neoplasia, for prevention of anal cancer. Methods: A total of 43 normal, 46 low-grade, 54 high-grade and 5 cancer biopsies were utilised for this study. Using annotated H&E samples, areas of interest were dissected and DNA extracted from formalin-fixed specimens. HPV typing was carried out by pyrosequencing a ~150bp fragment of the L1 major capsid protein using GP6+ as a sequencing primer. DNA methylation was measured for human gene EPB41L3 and four HPV targets (HPV16, HPV18, HPV31 and HPV33). A methylation score, S5, composed of a combination of the methylation levels of all the targets was calculated. The classification ability of the S5 score was evaluated by receiver operating characteristics (ROC) and area under the ROC curve (AUC). Results: The S5 score was significantly different between the four groups (P < 0.0001). The ROC curve comparing <AIN2 to AIN2+ cases (excluding cancers) had an AUC of 0.7871 (95% CI 0.7081 to 0.8662) with a P-value of <0.0001. For 90% sensitivity, the specificity was 38%. The majority of normal biopsies (86%) were not infected by any HPV type. With low-grade AIN, 48% of the biopsy samples contained high-risk HPV types, while 33% contained low-risk HPV types. With high-grade AIN, 84% of the samples contained high-risk HPV types and 8% had low-risk HPV types only. Conclusions: DNA methylation shows promise as a biomarker in the detection of high- grade anal neoplasia.
AuthorsNathan, M; Reuter, C; Lim, A; THAHA, MA; Sasieni, P; Sheaf, M; Lorinz, A; IANS (International Anal Neoplasia Society)
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