Correlation of Plasma Cell Percentages by CD138 Immunohistochemistry, Cyclin D1 Status, and CD56 Expression With Clinical Parameters and Overall Survival in Plasma Cell Myeloma

Plasma cell myelomas (PCMs) are traditionally diagnosed by the percentage (%) of plasma cells (PCs) in the bone marrow aspirate differential combined with clinical parameters and radiographic findings. PCs are most reliably quantitated in bone marrow (BM) tissues by CD138 immunohistochemistry (IHC). However, there are no correlations of % CD138+ cells with clinical parameters or overall survival (OS). The presence of cyclin D1 has correlated with worst prognosis, but cyclin D1 has not been correlated with routine cytogenetics. CD56+, although not significantly reported in reactive plasmacytoses, monoclonal gammopathy of undetermined significance (MGUS), nor in lymphoplasmacytic lymphomas (LPLs), has not been evaluated in borderline diagnostic (borderline) cases.It includes: (1) correlating the percentages of PCs by CD138 IHC, cyclin D1 status, and CD56 expression with clinical parameters and OS in PCMs, (2) correlating cyclin D1 status with routine cytogenetics in PCMs, borderline cases, and MGUSs, and (3) analyzing CD56 expression in PCMs, borderline cases, MGUSs, and LPLs.Bone marrow aspirates, BM touch preparations, and BM clot and/or biopsy sections with CD138/kappa/lambda IHC (44-PCMs, 9-MGUSs, 17-borderline cases, 3-LPLs, and 3-reactive plasmacytoses) were reviewed and stained with CD56 and cyclin D1.Increased CD138+ cells did not correlate significantly with clinical parameters or OS. Cyclin D1+ did not correlate with the presence of a t(11;14) by routine cytogenetics [although detected in all t(11;14)+ cases], clinical parameters, nor OS. CD56 expression was identified in PCMs, MGUSs, and LPL but not in reactive plasmacytoses. CD56+ did not distinguish PCMs, MGUS, and LPLs, and did not correlate with clinical parameters or OS. CD56 and cyclin D1 IHC were better evaluated in BM clot than biopsy sections.