An Immunohistochemical Survey of SNARE Proteins Shows Distinct Patterns of Expression in Hematolymphoid Neoplasia

Objectives: Five proteins from the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) complex family were studied in normal hematopoietic cells in bone marrow; normal lymphocytes at different stages of maturation and differentiation in bone marrow, thymus, tonsil, and lymph node; malignant lymphomas; and leukemias.

Methods: Sixty-eight reactive and 380 hematopoietic and lymphoid neoplasms were immunohistochemically stained for syntaxin 7 (STX7), vesicle-associated membrane proteins (VAMP2, VAMP7, VAMP8), and synaptosomal-associated protein 23 (SNAP23).

Results: STX7 has potential for being a useful marker for distinguishing between normal B precursors (hematogones) vs B lymphoblasts, as well as between the "popcorn" cells of nodular lymphocyte-predominant Hodgkin lymphoma vs the Reed-Sternberg cells of classic Hodgkin lymphoma or the B cells of T-cell, histiocyte-rich B-cell lymphoma. VAMP2 is uniquely expressed by both reactive and malignant plasma cells, in contrast to B-cell non-Hodgkin lymphoma. There is differential expression of SNARE proteins in normal and neoplastic lymphoid tissue depending on lymphocyte maturation stage.

Conclusions: Differential SNARE protein expression in the lymphoid system may have potential use in diagnosis and may offer clues to lymphoma biology. VAMP2 is a promising new plasma cell marker.