PROM1 and adenoma: Up to date, several CSC-related markers have been described in adenomas, e.g., CD133 [19], LGR5, PROM1 [20], IL-8 [21], OLFM4, and ASCL2 [22], but more information is required to understand malignant transformation, despite current findings in the field [19,20,21,22,23].