For instance, CXCR1+ cells formed 19.3% of the dissociated tumor cells derived from Caki‐1 sphere xenografts in first round of transplants, and that proportion increased to 23.4% in the second round, and finally reached 34.4% in the third round of transplantation (Figure 4H,I). The gene discussed is CXCR1; the disease is neoplasm.