High-Level CD34 Expression on Megakaryocytes Independently Predicts an Adverse Outcome in Patients with Myelodysplastic Syndromes.
Guilin Tang, Sa A Wang, Medhu Menon, Bruce Woda, Suyang Hao. MD Anderson, Houston, TX; Umass Memorial Medical Center, Worceter, MA
Background: Studies have suggested that CD34 expression on mature megakaryocytes may favor a diagnosis of MDS and correlate with a lower platelet count. To better understand the clinical significance of CD34 expression on megakaryocytes in MDS, we conducted the current study to assess the expression of CD34 on the megakaryocytes, and its correlation with patients' clinicopathological features, including demographic information, cytopenia, BM findings, cytogenetics abnormalities, and overall survival.
Design: A total of 202 patients with a MDS diagnosis over an 8 year-period (2001-2008) were included. Immunohistochemical staining was performed on BM core biopsy sections. Antibody against CD34 was purchased from Dako Corporation (clone: QBEnd 10; 1:160 dilution). The percentage of CD34+ megakaryocytes was calculated as CD34+ megakaryocytes/total megakaryocytes. Cases with CD34+ megakaryocytes ≥ 20% were considered as positive. Otherwise, it was considered as negative or low-level non-significant staining.
Results: Positive CD34 expression on megakaryocytes was found in 29 MDS patients (14%); It is more commonly seen in hig-risk MDS patients; it is correlated with thrombocytopenia, higher blasts count, more frequent and poorer risk cytogenetic abnormalities, higher IPSS score (Table 1) and a shorter overall survival (Fig 1). Multivariate analysis showed that CD34 expression on megakaryocytes is an independent poor prognostic factor in MDS, with a hazard ratio of 2.53.
|CD34 Neg N=173||CD34 Pos N=29||P|
|BM Blasts (%)||4.2±1.8||6.4±2.2||0.02|
|Good||104 (60%)||11 (38%)|
|Int||38 (22%)||11 (38%)|
|Poor||31 (18%)||7 (24%)|
|Low||56 (32%)||9 (31%)|
|Int-1||74 (43%)||9 (31%)|
|Int-2||35 (20%)||4 (14%)|
|High||8 (5%)||7 (24%)|