Evaluation of argyrophilic nucleolar organiser regions (AgNORs) in multiple myeloma.

AIM To investigate the prognostic value of argyrophylic nucleolar organiser regions (AgNORs) in multiple myeloma. METHODS Bone marrow aspirates from 55 newly diagnosed patients with multiple myeloma were stained with the one step AgNO3 technique. The mean number of AgNORs in each plasma cell nucleus (AgNOR count) was tested for a possible correlation with other clinical and laboratory variables at presentation (clinical stage, substage, heavy and light chain isotype, haemoglobin concentration, platelet count, marrow infiltration rate, degree of skeletal lesions, M protein concentration, plasma cell morphology, and serum concentrations of calcium, albumin, lactate dehydrogenase, C reactive protein, and beta 2 microglobulin) and with outcome (response to first line treatment, first remission duration, and overall survival). RESULTS A significant association between mean (SD) AgNOR count was found only for clinical stage (stage I, 3.09 (1.19); stage II, 3.80 (1.53); stage III, 5.28 (1.79); p < 0.005) and, from all stage determinants, only for M protein concentration (high, 5.92 (1.80); low, 4.01 (1.92); p < 0.001). There was a linear relation between AgNOR count and serum M protein concentration for patients with both IgG (r = 0.450; p < 0.01) and IgA (r = 0.768; p < 0.002) producing multiple myeloma. CONCLUSIONS Unlike previous investigations, no clear prognostic value for the AgNOR count was found in multiple myeloma. Instead, the results indicate that the AgNOR count might be an index for M protein synthesis rate. This is consistent with other findings in tissues with low proliferative potential and high protein synthetic activity, and calls for a cautious interpretation of AgNORs in malignancies with similar features.