A study of miRNA expression and target gene regulation in the Xiphophorus and transgenic medaka Xmrk models have shown that in fish melanomas, miR-17, miR-18a, miR-20a2, miR-92a1, miR-126, miR-182, miR-210 and miR-214 were upregulated, and their target genes, RUNX1, HIF1A, TGFBR2, THBS1 and JAK2, were downregulated [115]. Here, JAK2 is linked to melanoma.