TFF3 and pachyonychia congenita: To investigate the diagnostic potential of TFF3 promoter hypomethylation, we used qMSP to analyze TFF3 promoter methylation levels in 15 BPH, 18 adjacent normal (AN), 11 prostate intraepithelial neoplasia (PIN), and 292 PC tissue samples from a large RP cohort with long clinical follow-up (Table 1, Figure 1A).