Validation of a New Flow Cytometry-Based Method to Discriminate Malignant From Normal Stem Cells In CML

Previously, leukemic stem cells in Chronic Myelogenous Leukemia could only be identified indirectly by using culture techniques. Jeroen J.W et al have developed a new flow cytometric approach that allows a direct discrimination of CML stem cells from their normal counterparts within single patient samples. CD34+CD38- leukemic stem cells could be discriminated from normal stem cells by high CD90 expression, which is a specific feature of CML stem cells, while CD90 expression is low on their normal counterparts.

Material: A total of 8 patients and 3 health controls were included in this study.

Health controls did not present CD90 molecular expression in stem cells. 100% of the patients presented different levels of CD90 in CD34+/CD38- cells. Our patients seemed to show an asociation between CD34+/CD38- stem cells which express CD90+ and bcr-abl levels. We have evolutive studies of 4 patients who are under treatment with imatinib; in those patients we apreciate decrease in the level of CD90 related to good response.

Our results confirm Jeroen's data; we think that this new technique will expand our possibilities to identify CML stem cell specific targets and may improve efficacy assessment of CML treatment as well.

García:Celgene: Research Funding.