Evaluation of the proliferative activity as an adjuvant helpful tool in the diagnosis of primary gastric lymphoma in gastrobiopsy.

Gastrobiopsy specimens obtained from 15 patients, in whom gastroscopy examination pointed to gastric cancer and primary gastric lymphoma was later diagnosed in surgical material after gastrectomy, were immunostained using the anti MIB-1 antibody to assess the proliferative index. A control study was carried out on representative surgical specimens from these patients and on 10 gastrobiopsy specimens from patients in whom histopathology revealed moderate/severe gastritis. The proliferative activity was assessed with respect to the type of lymphoma (primary gastric marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue MALT type vs. diffuse large B-cell lymphoma) and stage of the lymphoma, and we compared the proliferative indices between inflammatory infiltrate and lymphoma cells. There were significant differences in the proliferative indices between inflammatory infiltrate and lymphoma cells, with immunohistochemical reactivity for MIB-1 antigen being visible even in the case of markedly mechanically damaged (crushed) gastrobiopsy material and accompanying necrosis. There were also differences in the proliferative indices between the groups of lymphomas varying in stage, although without statistical significance. There were no statistical differences in the rate of proliferation between lymphomas varying in "malignancy". The present results argue for the auxiliary role of the assessment of proliferative activity in gastrobiopsy material facilitating differentiation between inflammatory infiltrate and neoplastic infiltrate, especially in cases where mechanical damage or necrosis do not allow for precise histopathological evaluation.