We detected SP cells in the RPMI-8221 MM tumor cell line and thus co-cultured Ctr-Ts with RPMI-8226 MM cell line and found that both non-SP and SP cells were still present (73% ± 3.5% and 7% ± 6%, respectively), while CD138.CAR-Ts eliminated better both cell subsets (11% ± 5% and 0.05% ± 0.03%, respectively) (Figure 5C). Here, SDC1 is linked to neoplasm.