LAUSR

Editor, Myeloma is a clonal plasma cell (PC) disorder characterized by presence of a monoclonal M band in either serum or urine and is identified clinically with the presence of myeloma defining events/ biomarkers of malignancy.[1] Although the use of flow cytometry to identify malignant PCs in myeloma is not included in the diagnostic guidelines, it provides useful information on clonality of malignant PCs and to identify aberrant markers expressed by them. The malignant PCs differ in immunophenotype from normal PCs as they aberrantly express CD56 in 75% cases, CD117 and CD20 in 30% cases each, CD28 in 15–45% cases, and CD27 in 40–50% cases and show a loss of CD19 in 95% cases and CD45 is variably positive.[2,3] After the advent of proteasome inhibitors like bortezomib and immunomodulatory drugs like lenalidomide, there is now a higher likelihood of achieving complete response.[4] Now the use of flow cytometry is being extensively employed to detect residual disease in the myeloma patients who achieve complete response and are candidates for autologous stem cell transplantation.[5,6]