**1.5 Polo-like kinase inhibitors**

Polo-like kinases (Plks) are a family of 5 highly conserved serine/threonine protein kinases. They play a key role in mitotic checkpoint regulation and cell division. Plk1 has been shown to be overexpressed in a range of human cancers, including non-small cell lung cancer, prostate, ovarian, breast, and colorectal cancer as well as AML [94–96].
