PLK4 and osteosarcoma: More importantly, PLK4 inhibitor has been applied in a variety of solid carcinomas such as osteosarcoma, lung carcinoma and pancreatic carcinoma.9–11 For instance, PLK4 inhibitor suppresses the osteosarcoma cell proliferation and induces the cell apoptosis in osteosarcoma or pancreatic carcinoma.10,11 Additionally, PLK4 inhibitor suppresses the cell viability in lung carcinoma cells, and inhibits the tumor growth in murine model of lung carcinoma9.