CD44 and cancer: The PPI network showed that SALL4 and ALDHI1A1 have interactions with other important cancer stemness genes and CSC markers such as NANOG, POUF5 (OCT4), SOX2, CD44, and CD133 (PROM1) as shown in Fig.2 A and B. Additionally, genetic interaction between SALL4 and ALDH1A1 was observed by GeneMANIA (Supplementary Fig. 1).