Similar to primary myeloma cells, the Igλ Hg myeloma cells are incapable of growth when cultured alone or cocultured with supporting stromal cells; they also have GEP signatures similar to those of the original patient's plasma cells, are molecularly classified [39] in the MMSET subtype, and express DKK1 (important in MM-induced bone disease) [33]. Here, DKK1 is linked to Miyoshi myopathy.