EML4-ALK-positive non-small cell lung cancer in a patient treated with azathioprine for ulcerative colitis.

EML4-ALK-positive lung cancer is a novel cancer entity associated with light or never smoking, younger age, and adenocarcinoma with acinar or signet-ring cell type histology. Another mutation of ALK with NPM, resulting in NPM-ALK fusion mutation, was described in patients with anaplastic large cell lymphoma (ALCL). It was subsequently reported in organ transplant recipients and patiens undergoing immunosuppressive therapy. We describe a case of lung cancer in a 36-year-old nonsmoking woman with ulcerative colitis treated with azathioprine, who was diagnosed with EML4-ALK-positive, metastatic lung cancer two months postpartum. Crizotinib 300 mg/day has been effective in maintaining response after chemotherapy failed. The resemblance of this case to ALK-positive ALCL in organ transplant recipients suggests that similar mechanisms may be responsible for the development of both ALKpositive lung cancer and ALCL in patients receiving immunosuppressive therapy. Tu mo ri, 98: e98-e101, 2012