PARP1 and thoracic cancer: We therefore examined drug response data in GDSC and found that the sensitivity (IC50) of thoracic cancer cells (including MPM cells) to the MEK inhibitor PD0325901 is most strongly and inversely associated with protein levels of PARP1, a key factor in SSB pathway: cancer cells with high levels of PARP1 are more resistant to MEKi (Fig. 3D).