CHEK1 and lung carcinoma: Our live imaging experiments revealed in real time that release of replication stress with a Chk1 inhibitor, which induces replication fork collapse (14), specifically triggers apoptotic death of Onc-p53 expressing cells, while the inhibitors slightly delay mitotic entry of p53-depleted cells emphasizing the dependency of the lung cancer cells harboring Onc-p53 on replication stress (Fig. 7A–D, Videos).