Less apoptosis in patients with 5q-syndrome than in patients with refractory anemia.

The WHO classification of hematological malignancies includes 5q-syndrome as a separate category within myelodysplastic syndromes (MDS). Clinically, patients with 5q-syndrome have a milder disease than patients with other MDS. The basis for this difference is not known. Identifying 5q-syndrome can be difficult because some of its morphologic and cytogenetic features are similar to those of other MDS. We compared apoptosis between 5q-syndrome and other refractory anemias. We found lower levels of apoptosis in 5q-syndrome as detected by less disruption of mitochondrial potential (P=0.008) and decreased annexin V positivity (P=0.01). Our results suggest that lower apoptosis in 5q-syndrome may explain the milder clinical course of the disease and distinguish 5q-syndrome from other MDS.