Clinical and pathological features of MGUS and MM cases analyzed.

Cases were progressively numbered and sorted in high and low CK2 expressing subgroups. Scoring method used was: 0 = 0–5% positive cells; 1 = 6–33% positive cells; 2 = 34–66% positive cells; 3 = 67–100% positive cells. Cases were defined as CK2 high if the sum of the scores for CK2α and CK2β was equal to or > 3 and CK2 low if the sum was < 3. Clinical staging was performed according to Durie-Salmon criteria and according to the International Staging System (ISS; albumin levels ≤ or > 35 g/L; β2microglobulin levels ≤ or > 3.5 mg/L) (43). M = male; F = female; PC = plasma cells; FISH =  fluorescence in situ hybridization; ND = not determined; NA = not assessable.