Indirect evidence for ATG involvement is provided in colorectal CSCs as well, where the combination of 5-fluorouracil (5-FU) with the ATG inducer melatonin inhibits PrPc, along with the expression of the stem cell markers Oct4, Nanog, Sox2, and ALDH1A1 while suppressing tumor growth, proliferation, and angiogenesis [31]. Here, PRNP is linked to neoplasm.