PLK1 and cancer: Thus, the frequently observed overexpression of PLK-1 and its oncogenic role in several cancers has led to the development of PLK-1-specific inhibitors, which have already been tested in dose escalation trials for adult acute myeloid leukemia, chronic myeloid leukemia, myelodysplastic syndrome, and in children with various solid tumors, but to our knowledge, not in infant leukemia so far [42].