Prognostic significance of CD56 antigen in newly diagnosed multiple myeloma: A real-world retrospective study

The prognostic value of plasma cell CD56 expression of patients with multiple myeloma (MM) has been reported in many studies, but the results are controversial. This study aimed to examine the prognostic significance of CD56 in MM patients. Eighty seven patients with newly diagnosed MM were enrolled in this study, and their clinical characteristics, immunophenotypes, and cytogenetics were retrospectively analyzed to explore the prognostic significance of CD56 expression. Multiparameter flow cytometry was used to detect MM in bone marrow samples from all patients. Patients were divided into 2 groups based on whether they expressed CD56: CD56 + group and CD56 - group. After 4 cycles of chemotherapy, the overall response rate of the CD56 - patients was lower than that of the CD56 + patients (60.0% vs 81.1%, P = .036). Survival analysis showed that the median progression-free survival (PFS) was 10 months for the CD56 - group and 27 months for the CD56 + group (P = .007). The median overall survival (OS) of patients for the CD56 - group was 25 months versus not reached in the CD56 + group (P = .010). In addition, among the high-risk patients detected by fluorescence in situ hybridization (FISH), the median PFS was 4 months for the CD56 - group and 16 months for the CD56 + group (P = .012). The median OS of the CD56 + group and CD56 - group was 36 months and 15 months, respectively, with statistically significant differences (P = .017). Our study confirmed that CD56 - patients with MM had a worse prognosis than that of CD56 + patients with MM. Among the patients with ≥ 2 high-risk cytogenetics, the existence of the CD56 negativity can further identify MM patients with poor PFS and OS.