POU5F1 and cancer: 5-FU was reported to be associated with cancer stem cell enrichment, enhancing stemlike traits in colon cancer cells [17], augmenting expression of stem cell markers like octamer-binding transcription factor 4 (Oct4) Oct4 and CD133, decreasing the expression of differentiation markers like CD24 [18–21], increasing the percentage of side population (SP) cells in lung adenocarcinoma cell line SPC-A1 [21], and increasing the ability to form colonies [18–20].