Expression of CD117 antigen on multiple myeloma and its significance

BACKGROUND OBJECTIVE: Leukocyte differentiation antigen CD117 is one of the targets that tyrosine kinase selective inhibitors work on. Whether CD117 is expressed on the cell surface,and the expression level are highly correlated with tyrosine kinase selective inhibitors. This study was designed to investigate the expression of CD117 on multiple myeloma (MM) cells, which may provide a theoretical evidence for the use of tyrosine kinase selective inhibitors in MM,meanwhile,the importance of CD117 expression on MM cells was estimated. METHODS: CD117, CD56, and CD54 were measured by three color flow cytometry with CD45/SSC gating strategy. RESULTS: Of 48 patients with MM, 17(35.5%) had positive CD117 expression on myeloma cells, 39 (81.2%) had positive CD56 expression, and 48 (100.0%) had positive CD54 expression. CD117 expression on myeloma cells was lower than CD56,and CD54. CD117 positive expression was positive correlated with the percentage of myeloma cells in bone marrow. CD117 positive in IgG type of MM was 64%, higher than other types such as light chain or IgA. CD117 positivity showed no significant difference in different stages (P 0.05), and in patients havent been pretreated, or relapsed after pretreated (P 0.01). In MM patients havent been pretreated, the reaction rate of VAD chemotherapy in CD117 positive cases was 71.4%, and showed no significant difference (P 0.05) compared with the reaction rate of 66.7%in CD117 negative cases. CONCLUSION: CD117 can be regard as the related tumor antigen of MM, and may be a valuable marker in the use of tyrosine kinase selective inhibitors, which inhibit the signal conduct to the target.