Anaplastic lymphoma kinase (ALK) has recently been found to be a critical cancer gene in cases of lung cancer, neuroblastomas and lymphomas. ALK inhibitors have recently shown significant activity in lung cancer patients with tumours that harbour the EML4-ALK gene rearrangement, but already drug-resistance is emerging. We have taken a lung cancer cell line H3122 (with the EML4-ALK rearrangement) and generated clones resistant to a small molecule inhibitor of ALK by serial exposure to the drug over 8 weeks. We now wish to characterise at the exome level whether the acquisiton of resistance has been accompanied by the development of new mutations that we can take forward for further study as the potential mechansims underlying the resistance. We therefore propose to exome sequence the parental NCI-H3122 cell line as well as drug-resistant clones.