Table 3. Immunohistochemical analysis.
| Tissue specimen | 12 | (100%) |
| Origin of specimen | ||
| Subcutaneous met | 8 | (66%) |
| Lymph node met | 2 | (17%) |
| Liver met | 2 | (17%) |
| CD117/c-kit | ||
| +++ | 1 | (8%) |
| ++ | 2 | (17%) |
| + | 6 | (50%) |
| − | 2 | (17%) |
| ND | 1 | (8%) |
| PDGF-Rα | ||
| +++ | 0 | (0%) |
| ++ | 0 | (0%) |
| + | 7 | (58%) |
| − | 5 | (42%) |
| PDGF-Rβ | ||
| +++ | 1 | (8%) |
| ++ | 0 | (0%) |
| + | 7 | (58%) |
| − | 4 | (34%) |
Biopsies were obtained from metastatic lesions of 12 study patients prior to the onset of imatinib therapy. Processing of tissue specimens, see Patients and Methods. The staining intensity of melanoma cells was graded as follows: +++, strong; ++, moderate; +, weak; −, negative. Met, metastasis; ND, not done.