Introduction: Multiple Myeloma (MM) is a highly heterogeneous disease that comprises 10% of hematological malignancies. Although the survival of MM patients has improved over time, most of the patients relapse throughout the disease course. New studies are needed to better elucidate the factors responsible for MM heterogeneity and poor prognosis and to find new treatment targets. Even though CD20 is a B cell antigen that disappears on plasma cells; its expression has been shown in about 20% of MM patients. Following the demonstration of the involvement of CD20 positive
precursor B cells in the development of MM, an increasing number of studies have focused on anti-CD20 therapies. However, the expected results could not have been obtained from these studies. CD20 positivity and MM survival relationship have not yet been demonstrated.
Methods and Patients: A total of 250 patients who were admitted to Ankara University School of Medicine, Department of Hematology outpatient clinic between 2010- 2020, were included in our retrospective study. CD20, CD38, and CD138 expression results as well as chromosomal abnormalities were obtained by bone marrow (BM) biopsy according to the international guideline recommendations. Disease stages were determined based on the international staging system (ISS) and autologous hematopoietic stem cell transplantation histories were recorded. An expression over 20% via flow cytometry was accepted positive for all markers. Here, we aimed to determine the relationship between overall survival (OS) and CD20, CD38, and CD138 expressions with bone marrow biopsy at the time of diagnosis. All statistical analyses were obtained via SPSS ver.21.0 Armonk, NY.
Results: The median age was 62 (30-86) years and the female to male ratio was 135/115. 24 (9.6 %) patients had positive CD20 expression at diagnosis. On multivariate analyses, age, sex, and CD20 expression did not correlate with lower OS; however as expected, multivariable analyses revealed strong positivity for CD138 at diagnosis was statistically significantly associated with a lower OS (p=0.043). FISH was used for cytogenetic analysis and t(11;14) and CD20 expression was found to be significantly correlated (p=0.030). Clarifying the MM-CD20 relationship will contribute to a better understanding of MM and the possibility of using anti-CD20 therapies.