POMC and neoplasm: Cluster 1, encompassing 30% of the ACTH-secreting tumors, included the pituitary ACTH-secreting tumors and one pancreatic ACTH-secreting tumor sample, while cluster 2, comprising 70%, included the remaining pituitary ACTH-secreting tumors and all lung ACTH-secreting tumors, with the lung ACTH-secreting tumors forming a distinct subcluster (Figure 9).