LRG1 and melanoma: Tumor and stromal cells within the tumor microenvironment (TME) can also be a source of LRG1, and circulating levels of LRG1 were previously shown to be correlated with disease progression, disease burden, and poor prognosis in different cancer types (e.g., gastrointestinal, lung, pancreatic, prostate cancer; refs. 35–41), but not melanoma.