Anaplastic lymphoma kinase (ALK) rearrangement in adult renal cell carcinoma with lung metastasis: a case report and literature review

Renal cell carcinoma (RCC) with anaplastic lymphoma kinase (ALK) rearrangement is rare, and the genetic profiles of the tumor have not been elucidated. Here, we report a case with recurrent papillary RCC and lung metastasis after nephrectomy for nearly 7 years. The patient first received sunitinib, whereas the drug toxicity was intolerable. Combined Immunohistology (IHC) and fluorescence in situ hybridization (FISH) revealed the patient has an ALK rearrangement, and the patient then was treated with crizotinib. The patient had good tolerance, and a partial response in the target lesions was achieved. In order to further understand the benefit of crizotinib in ALK-rearranged RCC, the patient was detected with whole exome sequencing (WES) to study her genetic profiles. Compared those of RCC cases without ALK rearrangement (nALK-RCC), the patient and nine RCC cases with ALK rearrangement (ALK-RCC) revealed unique genetic characteristics: 1) The common mutations that occurred in RCC were not found in ALK-RCC.; 2) A total of 11 co-existing mutations in ALK-RCC were found, and they occurred in nALK-RCC at a relatively low frequency. DNMT3A mutations were concurrent with ALK fusions in our case. These findings indicated a different genetic alteration pattern of ALK-RCC from nALK-RCC. Our case demonstrated the efficacy of crizotinib in an RCC patient with ALK rearrangement.