[1305] A Characterization of Angiogenesis and VEGF Expression in Gastric MALT Lymphoma, Chronic Gastritis, and Normal Stomach

G Turner, MJ Morgan, RK Orr, M Eldibany. Evanston Northwestern Healthcare, Evanston, IL

Background: Vascular Endothelial Growth Factor (VEGF) has been implicated in the development of solid tumor and hematological malignancies. In addition to promoting angiogenesis, VEGF increases microcapillary permeablility to tumor cell metastasis. Recent research in a mouse model has suggested that VEGF mediated angiogenesis is important in the development of Helicobacter-related, low-grade MALT lymphoma. This study examines vascular density and VEGF expression in gastric MALT lymphoma, chronic gastritis lymphoid aggregates and normal stomach.
Design: The L.I.S. was searched for gastric biopsy specimens diagnosed as MALT lymphoma and chronic gastritis. 16 paraffin embedded tissue blocks from 13 cases of MALT lymphoma and 17 blocks from 15 cases of chronic gastritis were retrieved. 9 cases of normal stomach were retrieved as controls. Sections from each block were stained with antibodies against CD34 to highlight vascular endothelial cells. A Chalkley counting grid was used to assess vascularity within areas of MALT lymphoma and chronic gastritis lymphoid aggregates. The average diameter was calculated for vessels within areas of MALT lymphoma and chronic gastritis lymphoid aggregates. The MALT lymphoma, chronic gastritis and normal stomach specimens were stained with antibody against VEGFA (Chemicon #MAB3734) and staining was assessed via light microscopy.
Results: The Chalkley counting grid overlayed CD34 stained vessels an average of 11.0 times per field in the cases of MALT lymphoma and an average of 5.6 times per field in the cases of chronic gastritis (P = <0.001). The average diameter of vessels in the cases of MALT lymphoma was 29.6 m and was 16.8 m in the cases of chronic gastritis (P= <0.005). There was no significant difference between VEGF staining of MALT lymphoma aggregates and VEGF staining of lymphoid aggregates in chronic gastritis. Gastric epithelium stained focally positive with antibodies against VEGF in most cases of MALT lymphoma, chronic gastritis and normal stomach.
Conclusions: Vascular density is increased in gastric MALT lymphoma as compared to chronic gastritis lymphoid aggregates. The average diameter of vessels in MALT lymphoma is approximately twice that seen in chronic gastritis. VEGF staining does not appear to be increased in gastric MALT lymphoma as compared to chronic gastritis lymphoid aggregates. Uninvolved gastric epithelial cells in MALT lymphoma, chronic gastritis and normal stomach stain focally with antibody against VEGF.
Category: Hematopathology

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 140, Tuesday Morning