Significance of aldehyde dehydrogenase 1 expression in stromal cells of diffuse large B-cell lymphoma

Abstract

Aldehyde dehydrogenase (ALDH) 1 is expressed in various stem/progenitor cells, including cancer-initiating cells (CICs). In the present study, ALDH1 expression was immuno-histochemically examined in diffuse large B-cell lymphoma (DLBCL). Unexpectedly, ALDH1 expression was occasionally detected in stromal cells, but not in lymphoma cells. Positively stained cells were CD68+ cells with voluminous cytoplasm and fascin+ cells with reticular morphology, designated as macrophages and dendritic cells (DCs), respectively. The presence of ALDH1+ macrophages was not correlated with stage, response to therapies and prognosis. However, cases with ALDH1+ DCs were mostly nodal, which showed a poorer response to therapies and a worse overall survival rate than cases without ALDH1+ DCs. The presence of ALDH1+ DCs appears to be involved in the malignant potential of DLBCL in lymph node.