Ki67 and 4F2 antigen expression as well as DNA synthesis predict survival at relapse/tumour progression in low-grade B-cell lymphoma.

Previous work has shown that parameters of cell activation studied on lymphoma biopsies can be used to discriminate between low-grade and high-grade non-Hodgkin's lymphomas and to predict prognosis in the low-grade malignancy group alone. We have now examined expression of several activation antigens and indicators of DNA synthesis in 29 patients with low-grade malignant B-cell lymphomas at the time of primary diagnosis and later at relapse and/or tumour progression. At both times, the level of 4F2 antigen expression examined by flow cytometry on cells in suspension as well as the number of Ki67 antigen-positive cells examined by immunohistochemistry were predictive of patient survival. DNA synthesis estimated by (3H-TdR) thymidine incorporation was of prognostic value at the second biopsy only. These parameters were more sensitive than histological demonstration of morphological transformation in secondary high-grade lymphomas in identifying high-risk patients at repeated biopsy. We propose that Ki67 or 4F2 expression or a marker of DNA synthesis (such as 3H-TdR incorporation or labelling index) should be evaluated when repeated biopsies are performed, in order to select patients for whom aggressive chemotherapy may be considered.