An immunohistochemical evaluation of c-kit (CD-117) expression in malignant melanoma, and results of imatinib mesylate (Gleevec) therapy in three patients

In order to determine whether imatinib mesylate (Gleevec), a tyrosine kinase inhibitor that binds the CD-117 (c-kit) receptor, may be of value in the treatment of malignant melanoma, an immunohistochemical analysis of 40 cases of primary and metastatic melanoma was undertaken. Thirty-five of the 40 cases showed 1+ or stronger labelling for CD-117 (up to a maximum of 4+). Three patients with neoplasms showing 4+ staining were selected for imatinib therapy. None responded. c-kit (CD-117) expression in melanoma appears to be common; however, the value of imatinib therapy remains to be proven.