CHEK1 and neoplasm: Finally, we studied the anti-proliferative effects of CHK1 inhibitors (i.e., AZD, Prexa, MK) in MCF-7 and Y537S tumor cell spheroids [7, 9] as well as in alginate-based cultures [22, 23] to understand if differences in the effect of these drugs exist in cells grown in 3D structures [45].