SCL TAL-1 EXPRESSION IN T-ACUTE LYMPHOBLASTIC-LEUKEMIA - AN IMMUNOHISTOCHEMICAL AND GENOTYPIC STUDY/

A comparative study of the immunohistochemical (Stem cell leukemia/T-c ell acute leukemia [SCL/TAL-1] protein expression) and genotypic (dele tions in the SCL/tal-1 gene) findings in T-acute lymphoblastic leukemi a (T-ALL) is presented. Formalin-fixed tissue from 50 cases of T-ALL w ere stained with a novel monoclonal antibody, 2TL 242, which recognize s SCL/TAL-1 protein. Twenty-four cases showed nuclear immunolabeling o f leukemic cells. Nuclear positivity was not evident in any other type of leukemia or lymphoma tested with the antibody. Genotypic analysis of 25 cases of T-ALL showed a deletion involving the SCL/tal-1 gene in nine cases. These results suggest that protein expression is not depe ndent on derangement of the SCL/tal-1 gene, because immunohistochemica l detection of the protein was noted in the presence and absence of a tal-dl deletion. Copyright (C) 1995 by W.B. Saunders Company