Do Bcl-2 and survivin help distinguish benign from malignant B-cell lymphoid aggregates in bone marrow biopsies?

Bcl-2 and survivin are cellular proteins that are known to be inhibitors of apoptosis and are commonly found in malignant tissues, including lymphomas. In previous studies, it has been shown that staining for bcl-2 can help distinguish between benign and malignant lymphoid aggregates in bone marrow biopsies. To determine whether staining for survivin expression in lymphoid aggregates can aid investigators in making this clinically important distinction, we stained bone marrow biopsies from 10 patients with benign lymphoid aggregates, and 15 malignant ones derived from B cells (six mantle cell, four follicular cells, two diffuse large cell, two small lymphocytic cell, and one marginal zone lymphoma) with antibodies to CD3, CD20, bcl-2, and survivin by an indirect immunoperoxidase technique. Whereas staining for bcl-2 was significantly stronger in the malignant lymphoid aggregates (P=0.001), both the control and malignant cases were almost uniformly negative for survivin expression. Only three cases (two mantle cell and one small lymphocytic lymphoma) showed very faint expression of survivin. Although bcl-2 and survivin both act to inhibit apoptosis, their expressions do not parallel each other. Survivin is not significantly expressed in either benign or malignant bone marrow aggregates, and therefore measuring its expression does not help distinguish benign from malignant B-cell bone marrow lymphoid aggregates.