Thyrotropin-Releasing Hormone Gene Methylation as a Potential Biomarker for Anal Intraepithelial Neoplasia

Anal cancer is high in men who have sex with men living with human immunodeficiency virus (MSM-LWHIV). This cancer is strongly associated with high-risk human papillomavirus (HR-HPV) infection. Anal cancer screening using cytology and high-resolution anoscopy (HRA) for diagnosis of anal intraepithelial neoplasia requires specialized expertise. Biomarkers for the diagnosis of abnormal anal cells are of interest. <i>Thyrotropin-releasing hormone (TRH)</i> methylation at cg01009664 was detected using a pyrosequencing assay to compare methylation patterns among different anal lesions. Our results demonstrated that <i>TRH</i> methylation was significantly hypermethylated in anal intraepithelial neoplasia (AIN3) (>20%) and AIN1-2 (>10%) but less methylated in normal (<10%) (<i>p</i> < 0.001). <i>TRH</i> gene methylation showed higher sensitivity than the cytology for predicting AIN1+ (75.96% vs. 25.37%, respectively) and AIN2+ (78.95%% vs. 19.23%, respectively). There was no significant correlation between <i>TRH</i> methylation and the percentage of CD4 in patients with HIV (<i>p</i> > 0.05). <i>TRH</i> methylation in anal swabs reflects the presence of anal intraepithelial neoplasia. Methylation analysis showed higher sensitivity than cytology for high-grade lesions and was independent of immune status. These findings support its use as a screening tool to preselect patients for HRA, potentially reducing unnecessary procedures while maintaining diagnostic accuracy.