CLOCK and osteosarcoma: Using this approach we screened a broad panel of cell models, including non-malignant breast epithelial MCF10A, cancer cell models of various entities (breast cancer, neuroblastoma, and sarcoma) as well as two knockout variants of osteosarcoma U-2 OS cells with a single deletion in the circadian clock gene Cry1 (U-2 OS sKO) or paired with a deletion in the Cry2 locus28 (U-2 OS dKO).