FCER2 and neoplasm: It is important to note that CD10, CD22 and CD23 have been reported as being expressed in 3%, 33% and 61% of patients.[6] The observation that these antigens were not expressed in the majority of RPCI-WM1 cells was not altogether unforeseen as this cell line was derived from a terminally advanced stage WM patient and suggests the shedding of “typical” surface antigens and upregulation of others (i.e. CD28) by the tumor clone, perhaps to retain its tumorigenicity.