Expression of Microphthalmia Transcription Factor in Sentinel Lymph Nodes of Patients with Melanoma

Background: Sentinel lymph node biopsy is widely used in the management of melanoma patients. Multiple markers are used to stain sentinel lymph node tissue including S100, HMB-45 and melan A with different success. We investigated, for the first time, the use of Microphthalmia transcription factor (Mitf) staining in a larger series of sentinel lymph nodes. Mitf is a transcription factor essential for the development and survival of melanocytes. It has been introduced recently as a sensitive and specific marker for melanomas. Methods: Thirty patients with cutaneous melanoma were included in our study: twenty patients underwent sentinel lymph node biopsy; ten patients underwent complete lymph node dissection for clinically positive disease. Results: Ten out of twenty sentinel lymph nodes were negative for tumor cells and showed no Mitf staining. Out of the ten positive sentinel lymph nodes, eight were also positive for Mitf. Only four out of the ten clinically positive lymph nodes stained for Mitf. Conclusions: We conclude that Mitf can be used as an additional marker for evaluating sentinel lymph nodes in patients with melanoma. In addition, our results imply that Mitf is involved in melanoma differentiation.