APPL1 and prostate cancer: Here, the expression pattern of the biomarker panel was assessed in atypical intraductal proliferative lesions in prostate cancer, revealing distinct patterns of expression with Appl1, Sortilin, and Syndecan-1, including (1) labelling of Appl1/Sortilin in flat/tufting HGPIN and (2) labelling of Appl1, Sortilin, and Syndecan-1 in MP HGPIN and AIP.