THE ASSESSMENT OF PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IMMUNOSTAINING IN PRIMARY GASTROINTESTINAL LYMPHOMAS AND ITS RELATIONSHIP TO HISTOLOGICAL GRADE, S+G2+M PHASE FRACTION (FLOW CYTOMETRIC ANALYSIS) AND PROGNOSIS

PCNA is a nuclear protein that is synthesized in late G1 and S phases of the cell cycle and is, therefore, correlated with the cell proliferative state. A new monoclonal antibody (PC10) to genetically engineered PCNA has been shown to label proliferating cells in formalin-fixed paraffin-embedded normal human tissues. Previous studies in lymphomas, using various markers of cell proliferation, have shown a strong correlation between indices of cell proliferation and histological grade. These studies have shown that within each histological subtype there is often a wide range of proliferative indices and that these may be of some prognostic significance. Thirty-one gastrointestinal lymphomas were studied. Our results show that there is a good correlation between PC10 index and histological grade of tumour (0.01 > P > 0.001) and also a significant relationship between PC10 index and S + G2 + M phase fraction as measured by flow cytometric analysis (r2 = 0.62; P < 0.01). Twenty-three cases were available for survival analysis. In these cases a high PC10 score correlated with poor survival (P = 0.04). Based on this series, it appears that there is a significant relationship between PC10 index and histological grade, and between PC10 index and S + G2 + M phase as measured by flow cytometric analysis. In addition, our results suggest that a high PC10 index is an adverse prognostic factor in primary gastrointestinal lymphoma.