The results of tumorsphere formation assay have shown that the number of tumorsphere is decreased when Stat3 is suppressed by Napabucasin (BBI608), which could inhibit gene transcription driven by Stat3 and cancer stemness properties 15 (NCI-N87: P<0.0001; SGC-7901: P<0.0001), besides, knockdown of mesenchymal splice isoform of CD44 (CD44s) could also inhibited the formation of tumorsphere (NCI-N87: P<0.0001; SGC-7901: P<0.0001; Figure 5A & B). Here, STAT3 is linked to cancer.