ROR1 and neoplasm: ROR is a small RTK family, including ROR1 and ROR2 which were first characterized in 1992 form SH-SY5Y neuroblastoma cell line.277,278 The two receptors are highly expressed during embryogenesis and not expressed in adult tissue; however, an increased expression of the ROR receptors is observed in tumor tissues with increased cell proliferation.279–282 According to Zhao et al., no mutation in ROR1 have been found yet,283 however the overexpression of ROR1 itself is a cause of increased proliferation and cell growth, in malignancies, ischemia and diabetes.284–286