Based on our results obtained in patients with metastatic melanoma,4 we decided to model the effects of PROM2 expression on metastatic potential, using two different types of murine models: (i) xenografts derived from two melanoma cell lines, A375 or Sk‐Mel‐28; (ii) five patient‐derived melanoma xenografts from metastasis biopsies, named XM1 to XM5. The gene discussed is PROM2; the disease is metastatic melanoma.