BCR and chronic myelogenous leukemia, BCR-ABL1 positive: However, it is noteworthy to mention that, thought nursing care cost maintenance is high and time-consuming, a more straightforward leukemic mice model can be established using BALB/c nude mice, which appears to be an immunocompromised mouse strain, and the transplantable human chronic myeloid leukemia K562 cells, which express BCR-ABL (e.g., [37]).