Apparent expansion of CD34+ cells during the evolution of myelodysplastic syndromes to acute myeloid leukemia

Abstract

30%). This was associated with a decreasing trend in the overall myeloid labeling index (LI: RA/RARS 25.8%, RAEB(t) 24.6% and sAML 21.5%). This decrease in overall myeloid LI is due to an exponential increase in the proportion of CD34؉ cells of the proliferating compartment during MDS evolution (RA/RARS 0.35%, RAEB(t) 1.44% and sAML 11.98% of all S-phase cells). These CD34؉ cells appeared to proliferate more slowly than their more mature CD34 negative counterparts, since we found a progressive increment in the mean total cell cycling time (T c ) of all myeloid cells during MDS progression (RA/RARS 39.8, RAEB(t) 45.2 and sAML 65.8 h). This study showed that during MDS evolution to sAML the CD34 ؉ compartment develops a growth advantage leading to apparent expansion.

Expression of FLIPLong and FLIPShort in bone marrow mononuclear and CD34+ cells in patients with myelodysplastic syndrome: correlation with apoptosis

“…These results further support the concept that FLIP L was expressed predominantly in myeloblasts and probably upregulated with disease progression. As the CD34 þ blast population tends to expand with disease progression, and the rate of apoptosis declines, 22,23 the expression of FLIP L in CD34 þ precursors is also consistent with this model.…”

Expression of tumor necrosis factor–related apoptosis-inducing ligand, Apo2L, and its receptors in myelodysplastic syndrome: effects on in vitro hemopoiesis

“…Conversely, in advanced MDS, the abnormal precursor pool has expanded and is a major contributor to overall hemopoiesis. 34 As a consequence, elimination of those cells should result in a decline in colony formation. An alternative consideration might be that cellular responses to TRAIL signaling differed for different disease stages.…”