To exclude the possibility that the inhibitory effects of stromal YAP1 deficiency on melanoma progression shown in Fig. 1 were contributed by YAP1 loss in other α-SMA-expressing cell types in recipient mice, we established a human melanoma xenograft model using a combination of GFP/M50 or shYAP1-GFP/M50 with A375 melanoma cells (Fig. S5A). This evidence concerns the gene ACTA1 and melanoma.