This is a fascinating but dense paper on molecular profiling of lung NENs. A few take-home points: -- There arefour strikingly different molecular groups that vary in patient characteristics, genomic and transcriptomic profiles, microenvironment, and morphology. -- A new molecular group, enriched for highly aggressive supra‐carcinoids that displayed an immune‐rich microenvironment linked to tumour-macrophage crosstal -- There appears to be an undifferentiated cell population within supra-carcinoids showing the transcriptomic similarities between supra-carcinoids and the recently identified atypical small cell lung cancer tumours, further demonstrating their molecular link to high-grade lung neuroendocrine carcinomas -- There appear to be distinct evolutionary trajectories, suggesting that molecular groups are determined early in tumourigenesis by genomic events, and that transitions between groups, though infrequent, are possible for supra-carcinoids link.springer.com/article/10…