ABSTRACT.We examined the effect of transforming growth factor-b inducible early gene-1 (TIEG1) on the apoptosis of leukemic cell lines and expression of B-cell lymphoma 2 (Bcl-2) and phosphatase and tensin homolog (Pten). Four leukemic cell lines (HL-60, U937, Raji, and K562) were treated with 0, 1, 5, 10, and 20 ng/mL TIEG1, respectively. The cell growth inhibitory ratio was assessed using the MTT assay. An inhibitory curve was drawn, and half-maximal inhibitory concentration was calculated. Additionally, 1640 culture medium containing 10 ng/mL TIEG1 was used to culture leukemic cell lines for 0, 6, 12, 24, and 48 h. The apoptosis of each cell line at different time points was detected by flow cytometry. Total RNA was extracted before reverse transcription-polymerase chain reaction. The products of this reaction were analyzed by electrophoresis, and the expression of Bcl-2/Bcl-2-associated X protein (Bax) and Pten were detected. After treatment with TIEG1, proliferation of the 4 leukemic cell lines was inhibited both time-and dose-dependently. During apoptosis induction, the expression of Bcl-2 was decreased and the expressions of Bax and Pten were increased in the 4 leukemic cell 1969 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (1): 1968-1974 (2015 Effect of TIEG1 on leukemic cells lines induced by TIEG1 (P < 0.05). TIEG1 can inhibit the proliferation of leukemic cells and induce their apoptosis in a time-and dosedependent manner. A close relationship exists between Bcl-2/Bax and Pten expression and cell apoptosis induced by TIEG1.