Diagnosis of sentinel lymph nodal metastases in malignant melanoma. Usefulness of genetic diagnosis by reverse transcriptase-polymerase chain reaction

Sentinel lymph node (SLN) biopsy has been performed in 25 patients with malignant melanoma for the last four years at the Department of Dermatology, University of Occupational and Environmental Health. SLNs were identified by using both patent blue dye and redionucleotide-labeled colloid methods. The removed SLNs were subjected to routine haematoxylin-eosin staining and immunohistochemical stainings for Melan-A, S-100 protein and HMB45, and 10 of 25 cases had positive SLN metastases. In 8 cases, mRNA for malignant melanoma related molecules, gp100, MART-1 and tyrosinase, was analyzed by RT-PCR, and 7 of 8 cases gave agreement with the histopathological results. One case had negative SLN metastasis on histopathological examination but exhibited amplification of mRNA for the melanoma-related molecules on RT-PCR analysis. (author)