Expression of enolases in B cell tumors

Frozen lymph node biopsy specimens from 38 patients with B cell tumors, including 5 with childhood non-T-ALL and 3 with reactive lymphadenitis, were investigated using a direct immunohistochemical method to detect alpha-, beta- and gamma-enolases. alpha-Enolase-positive cells were not observed in reactive lymphadenitis. On the contrary, almost all the lymphocytes including germinal center cells were positive for beta-enolase. Small lymphocytes in the mantle zones were negative, centrocytes were negative or weakly positive, the majority of centroblasts were strongly positive and the remaining were weakly positive for gamma-enolase. In all 5 patients with childhood non-T-ALL, leukemic lymphocytes were strongly positive only for alpha-enolase. In all 33 patients with B cell lymphoma, lymphoma cells were positive for beta-enolase. In many patients with follicular lymphoma, lymphoma cells were positive only for beta-enolase. Four of five patients with malignant lymphoma, diffuse, small cleaved cell, showed the reactivity of alpha-, beta+, gamma+-enolases in lymphoma cells. Our results suggest the possibility of the two isoenzyme switches from alpha- to beta-enolase and from alpha- to gamma-enolase in the B lymphocyte lineage accompanying differentiation, similar to those of skeletal muscles and neurons.