Cancer Stem Cells of Diffuse Large B Cell Lymphoma Are Not Enriched in the CD45(+)CD19(-) cells but in the ALDH(high) Cells

Although the existence of cancer stem cells (CSCs) has been suggested in diffuse large B cell lymphoma (DLBCL), there is still no definitive marker. CD45(+)CD19(-) has been regarded as a potential marker of CSCs in mantle cell lymphoma (MCL). So, we explored the role of CD45(+)CD19(-) in DLBCL. However, both CD45(+)CD19(-) cells and CD45(+)CD19(+) cells did not generate tumors until more than 100,000 cells were inoculated in NOD/SCID mice, even CD45(+)CD19(+) cells generated more and larger tumors, as well as the soft agar colony formation in vitro; The aldehyde dehydrogenase (ALDH) activity was also identified in this study. Only 1,500 ALDH(high) cells were enough to generate tumors in mice while the same number of ALDH(-) cells were not. Moreover, both groups formed tumors when more cells were inoculated, but ALDH(high) cells formed more and larger tumors. The similar result was obtained in vitro clonogenicity experiments. OCT4, SOX2, Nanog, and ABCG2 genes did not show any difference in CD45(+)CD19(+), CD45(+)CD19(-), ALDH(high) and ALDH(-) cells. Taken together, CSCs are not enriched in the CD45(+)CD19(-) cells but in the ALDH(high) cells in DLBCL cell lines.