One subpopulation among the cancer cells (PDAC_C1 cluster) had a more extensive expression of several well-known CSC markers43, such as CD133, CD44, KLF4, and ALDH1A1 (Supplementary Fig. 2b), indicating that this subpopulation could more closely resemble PDAC CSCs in our cell lines grown as spheres. The gene discussed is ALDH1A1; the disease is cancer.