TP53 and T-cell leukemia: For example, we and others have reported that the human T-cell leukemia cell line MOLT-4, which is highly radiosensitive and exhibits p53-dependent radiation apoptosis [20], is not suppressed by radiation-induced apoptosis even in the presence of Act.D, concluding that the contribution of the p53 transcription-independent pathway is dominant in the irradiated cells [21,22].