T-cell leukemia development in Tcra-deficient TEL-JAK2 transgenic mice. (A) Kaplan-Meier leukemia-free survival curves for EμSRα-TEL-JAK2 transgenic mice deficient or not for the Tcra gene show no statistically significant differences. Mice were monitored for disease as described in “Materials and methods.” The number of mice in each group is given in parentheses. (B) Three representative TEL-JAK2/Tcra^−/− transgenic tumors (nos. 50, 56, and 57), 2 representative TEL-JAK2/Tcra^+/− tumors (nos. 31 and 35), and control thymocytes were double-stained with CD4 and CD8α antibodies and analyzed by flow cytometry. (C) Thymus, spleen, and lymph node weights were determined for Tcra^+/− (n = 12) and Tcra^−/− (n = 15) TEL-JAK2 transgenic mice. **P < .01; ***P < .001 (unpaired t test). Average organ weight is indicated by horizontal bars. (D) Cell surface immunostaining of 3 representative TEL-JAK2 tumor cases (nos. 50, 56, and 57) using antibodies against CD3ϵ, TCRβ, CD24, and CD25 or an isotypic control monoclonal antibody.