ABSTRACT
We present a case report of a patient relapsing after anti-CD38 treatment (daratumumab). The phenotype of the disease changed during this treatment, and the myeloma clone became CD38 negative and daratumumab refractory. We expected clonal shift, however, based on immunophenotyping, cytogenetics and arrayCGH; the clone was identical as before daratumumab-based treatment with the exception of CD38 negativity. We suggest that the downregulation or loss of CD38 might be an epigenetic "escape mechanism" of malignant plasma cells from antibody-based treatment. The aim of our study was to point out the pitfalls of immunophenotyping and cytogenetics in both assessing the minimal residual disease and clone detection after monoclonal antibody-based therapy.
Subject(s)
Multiple Myeloma/diagnosis , Multiple Myeloma/metabolism , ADP-ribosyl Cyclase 1/antagonists & inhibitors , ADP-ribosyl Cyclase 1/metabolism , Antibodies, Monoclonal , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biomarkers , Comparative Genomic Hybridization , Cytogenetic Analysis , Humans , Immunophenotyping , Male , Middle Aged , Molecular Targeted Therapy , Multiple Myeloma/drug therapy , Multiple Myeloma/genetics , Prognosis , RecurrenceABSTRACT
BACKGROUND: The genome of multiple myeloma (MM) clonal plasma cells is characterized by genetic changes of prognostic importance. Disease progression is accompanied by a number of secondary chromosomal aberrations including chromosome 8. We focused on the detection of chromosome 8 aberrations in patients with MM who were examined at 2 different phases: diagnosis and progression/relapse. PATIENTS AND METHODS: A total of 62 patients with MM were examined at the time of diagnosis and at relapse/progression. The median age was 64 years (range, 39-78 years); the study included 29 males and 33 females. We analyzed bone marrow samples for detecting aberrations on chromosome 8 by the fluorescence immunophenotyping and interphase cytogenetics as a tool for the investigation of neoplasms (FICTION) and fluorescence in situ hybridization methods with specific probes. RESULTS: Chromosome 8 aberrations were detected in 24 (38.7%) patients at diagnosis and in 29 (46.8%) patients at progression/relapse. Only 5 (8%) patients developed additional chromosome 8 changes at progression/relapse. The aberrations were heterogeneous, involving numerical and structural changes of the MYC gene. Aberrations of the short arm of chromosome 8, involving the genes TRAIL-R1/-R2, were less frequent (4 of 62 patients, 6.4%). All aberrations of chromosome 8 were accompanied with additional changes and with an advanced clinical phase of the disease. This finding significantly influenced the overall survival of patients. CONCLUSION: In the current study, chromosome 8 aberrations were highly heterogeneous, were presented at diagnosis in patients with advanced clinical stage, and were associated with worse overall survival. We have not confirmed the increase of frequency aberration of chromosome 8 in disease progression. The findings demonstrate the importance of fluorescence in situ hybridization examination of chromosome 8 in newly diagnosed patients with MM.
