Abstract
Introduction: Clusters of Differentiation (CD) are of significant importance for cell identification, disease prognostication and treatment options in hematological neoplasms. Several monoclonal antibodies are in use or in development which target cells with unique surface CD and could therapeutically function via multiple mechanisms. CD30, a member of the tumor necrosis factor receptor superfamily, is found mainly in classic Hodgkin lymphoma in addition to other B- and T-cell lymphomas and can be targeted by brentuximab. CD30 expression in patients with chronic myelomonocytic leukemia (CMML) is unknown.
Methods: The clinical data for all patients diagnosed with CMML at Mayo clinic from 2009 to 2011 were reviewed after appropriate IRB approval was obtained. Patients with chronic myelomonocytic leukemia and available tissues and blocks were included. CMML was classified based on World Health Organization 2008 classification. CD30 staining was done by immunohistochemistry and was called positive if 1% of total nucleated cells stain positive. The bone marrow biopsies, labs, and cytogenetic analysis at time of initial diagnosis for all cases were performed or reviewed at our center. Survival estimates were calculated using Kaplan-Meier curves, and univariate and multivariate analyses were based on log-rank testing using JMP software version 10.
Results: Out of 272 patients with confirmed diagnosis of CMML, 47 cases were selected for CD30 testing. Median age was 72 years, with 74% being males. Median hemoglobin was 11 gm/dL, white blood cell count (WBC) 11 x109/L and platelets of 63 x109/L. With a median follow up of 14.8 months, leukemic transformation (LT) was seen in 11% and CMML patients had median overall survival (mOS) of 19 months.
Out of 47 patients, 27 (57%) patients stained at least 1% positive for CD30 (CD30+) with a median positivity for CD30 being 4% (range, 1-13%). Upon comparing the 2 groups, CD30+ CMML patients had a higher platelets (90 vs 51 x109/L, p=0.045) and more females (37% vs 10%, p=0.03) but no significant difference for hemoglobin, wbc, platelets, peripheral blood and bone marrow blasts, diploid cytogenetics percentage, and LT. Upon comparing mOS for the 2 groups, CD30+ patients had a longer survival compared to CD30- patients but this was not statistically significant (22.7 vs 14.8 months, p =0.3).
Conclusion: CD30 expression was found positive in more than half (57%) of the patients although median positivity was 4%. Upon comparison between the CD30+ and CD30- CMML patients, CD30+ patients had higher platelets count and more females. CD30 positivity had a positive impact on mOS but was not statistically significant, possibly due to the small sample size. Targeting CD30 in CMML patients may be of interest in clinical studies.
No relevant conflicts of interest to declare.
