Here, we have detected the presence of myeloma cells with low expression of CD138 in the absence of bone marrow microenvironment cells and under these circumstances, the population of CD138low cells does not seem to represent a more immature compartment since it does not express the B-cell associated markers CD19, CD20 and CD27 and it does not show a less differentiated morphology. Here, CD27 is linked to plasma cell myeloma.