The present invention is in the fields of cell biology, immunology and oncology. Specifically, the invention relates to humanized antibodies that recognizes v 6 integrins which comprises a variable region of nonhuman origin and at least -a portion of an immunoglobulin of human origin. The invention also relates to processes for their preparation, to pharmaceutical compositions comprising them and to methods of treating various diseases by administering humanized anti- v 6 antibodies. The invention also relates to the identification of differential expression of the integrin ±v²6 on the surfaces of tumor cells and tissues, the use of this differential expression in determining the metastatic potential of tumor cells, and methods of diagnosis and treatment/prevention of tumor metastasis and for elimination of residual metastatic tumor cells using ligands, particularly antibodies, that bind to integrin ±v²6.