Recent studies have shown that the receptor tyrosine kinase-like orphan receptor 1 (ROR1) is selectively expressed on the surface of B-cell chronic lymphocytic leukemia and on some B-cell lymphomas (including mantle cell lymphoma, marginal zone lymphoma, follicular lymphoma), whereas normal B cells and other normal cells do not express ROR1 [94,95]. Here, ROR1 is linked to marginal zone lymphoma.