PROM2 and metastatic neoplasm: Since PROM2 mRNA expression gradually increased after time lapses ranging from 30 to 120 min from cell detachment in vitro, and in lung metastases derived from the A375 PROM2 clone as compared with the native clone (Figures 5A and B), we decided to build a new model to study the metastatic disease and mimic the runaway metastatic process frequently observed in patients.