Membrane Proteases in Human Malignant Lymphomas
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The activities of membrane-bound proteases: γ-glutamyltranspeptidase (γ-GTP), microsomal alanyl aminopeptidase (mAAP, formerly APM), glutamyl-aminopeptidase (EAP, formerly APA) and dipeptidyl peptidase IV (DPP-IV) -were examined in 11 cases with non-Hodgkin's malignant lymphomas (NHL), in 7 cases with Hodgkin's disease (HD) and 8 cases with reactive follicular hyperplasia (RFH) by means of enzyme histochemical methods. The results indicated that there was correlation between grade malignancy of NHL and γ-GTP activity: high grade NHL displayed strong γ-GTP activity, whereas low grade NHL showed weak activity. HD also showed various patterns of γ-GTP activity. Of 7 HD examined, 4 showed strong γ-GTP activity and 3 other were slightly positive. The lymphoid cells in RFH and neoplastic cells in NHL and HD failed to exhibit mAAP- and EAP activities. The activities of these enzymes were seen in stromal cells. Variable numbers of small mature lymphocytes in RFH and in malignant lymphomas showed dot-like DPP-IV activity. Thus, the study of γ-GTP activity may be a valuable diagnostic feature in the distinction between NHL of low and high grade malignancy and may prove to be a useful marker with which to predict drug- and irradiation resistance. Moreover, mAAP- and EAP pattern in the lymphoid cells may be useful in defining in lymph nodes the metastatic tumour cells with strong activities of these enzymes.
- ACTA HISTOCHEMICA ET CYTOCHEMICA
ACTA HISTOCHEMICA ET CYTOCHEMICA 30(5), 513-516, 1997-10-01
JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY