In a paper published online in advance in Modern Pathology, researchers at Massachusetts General Hospital and Harvard Medical School discuss the histologic and cytomorphologic features of ALK-rearranged lung adenocarcinomas, which they determined in a fluorescence in situ hybridization-based examination of resection, excision, small biopsy, and cytology cell block specimens from 104 ALK-positive and 215 ALK-negative samples from primary and metastatic sites. Based on the results of their FISH studies, the researchers developed a morphology-based scoring system for predicting ALK rearrangements in lung adenocarcinomas, which they say "predicted ALK rearrangements in a new cohort of 78 lung adenocarcinomas (29 ALK[-positive] and 49 ALK[-negative]) with a sensitivity of 88 percent and a specificity of 45 percent."
In a separate but related paper pertaining to ALK changes, investigators at the Mayo Clinic in Rochester, Minn., report on the frequency of ALK alterations in adult renal cell carcinomas, as well as on the associated clinicopathologic features and outcomes. The Mayo Clinic team used FISH to look for ALK alterations in RCC samples from a cohort of 534 consecutive surgically treated adult patients, finding ALK rearrangements in only two of them. "Both showed similar histologic features and the patients had a poor outcome," the authors write in Modern Pathology. Of the 534 samples they studied, the researchers identified ALK copy-number gains in 54 of them. Further, the researchers found that, "in clear cell type RCC, ALK copy-number gain was significantly associated with tumor size and nuclear grade, and with a worse 10-year cancer-specific survival [versus] similar patients lacking ALK copy-number gain," they write.