CHEK1 and mesothelioma: Counterintuitively, an important regulator of DNA damage-mediated cell cycle arrest, checkpoint kinase 1 (CHEK1), is overexpressed in 50% of mesothelioma cases compared to normal pleural tissue, and CHEK1 knockdown leads to synergistic apoptosis in mesothelioma cell lines when combined with the chemotherapeutic drug, doxorubicin [39].