MKI67 and Miyoshi myopathy: Traditional prognostic factors in MM measure plasma cell proliferation (plasma cell labeling index, Ki-67), plasma cell mass (clinical stage, plasmacytosis), or the status of the patient (hemoglobin, calcium, creatinine, albumin), in addition to β2-microglobulin that in one variable measures a combination of cell proliferation, cell mass, and renal function.