KRAS and chordoma: In recent years, zebrafish models have been developed to investigate whether the mutations of human H-RAS, N-RAS, K-RAS or zebrafish k-ras caused tumorigenesis, including models that illustrate chordoma [68], melanoma [69], rhabdomyosarcoma [70,71], brain tumors [72], gill tumors [73], liver tumors [74], pancreatic tumors [75], and other tumors that faithfully recapitulate human disease symptoms.