ACUTE ERYTHROLEUKEMIA - EVALUATION OF 48 CASES WITH REFERENCE TO CLASSIFICATION, CELL-PROLIFERATION, CYTOGENETICS, AND PROGNOSIS

We evaluated 48 archival cases of acute erythroleukemia and divided th em into 3 groups: M6a, corresponding to the traditional French-America n-British M6 category; M6b, which is pure erythroleukemia; and M6c, in which myeloblasts and pronormoblasts each account for more than 30% o f cells by the French-American-British exclusion criteria. No signific ant differences were noted among the subtypes for ratio of males to fe males; age; or exposure to toxins, alcohol, or both. However, compared with the patients in the M6a group, patients in the M6b and M6c group s demonstrated a statistically significant increase in cytogenetic abe rrations, proliferation markers (proliferating cell nuclear antigen an d Ki67), and ringed (type III) sideroblasts. Marked survival differenc es were noted between the M6a (30.1 +/- 29.5 months) and M6b (3.15 +/- 4.2 months) groups, with patients in the M6c group demonstrating an i ntermediate prognosis (10.5 +/- 12.7 months). Chemotherapeutic regimen s induced remission in all treated patients in the M6a and M6c groups but did not appear to affect the M6b group. However; the patients in t he M6c group remained in remission for a significantly shorter period of time than did patients in the M6a group. Overall, survival appeared to depend on the ratio of pronormoblasts to myeloblasts at diagnosis and demonstrated a rapid decline with increasing pronormoblast and dec reasing myeloblast counts. We must, therefore, devise chemotherapeutic regimens that target both blastic components of this disease.