ROR1 and neoplasm: The immunohistochemical analysis showed that 22.0405.aF does not downregulate ROR1 antigen expression significantly on tumor cells, as no significant differences in either percentage of positive cells or obvious change in intensity of the ROR1 staining were observed, between vehicle-treated tumors and 22.0405.aF-treated tumors, confirming the results from flow cytometry analysis.