Seto K, et al. - Researchers analyzed the genomic status, studied the clinicopathologic features, and assessed whether anaplastic lymphoma kinase (ALK) mutations were associated with occult lymph node (LN) metastases via 459 retrospectively evaluated Japanese patients who had a pulmonary resection of clinical N0 stage (cN0) adenocarcinomas between January 2012 and December 2015. The outcomes highlighted the frequency of PET- and CT-negative occult LN metastases in resected adenocarcinomas with ALK rearrangement. Compared with ALK-negative adenocarcinomas, ALK rearrangements were associated with a significantly higher incidence of occult LN metastasis.