We ranked patient samples from available datasets based on ALDH1A3 RNA levels, and then selected ALDH1A3-high and ALDH1A3-low patients from each cohort; top and bottom 10% for TCGA52 and Lund (primary and metastatic melanomas),53 and top and bottom 25% for Bergen dataset (stage IV melanomas)54 (Figure S1G). Here, ALDH1A3 is linked to melanoma.