Aldehyde dehydrogenase 1 family, member A1 (ALDH1A1) was used as a marker to isolate BCSCs [35] from two established cancer cell lines, 5637 and UM-UC-3, by flow cytometry (Figure 1(a)), and RNA m6A methylation abundance was evaluated by the m6A RNA quantification kit. Here, ALDH1A1 is linked to cancer.