RESUMO
BACKGROUND: Neuropeptide Y (NPY) is widely found in the nervous system and has a role in numerous physiologic processes. In addition, NPY receptors are expressed in neuroendocrine tumors, breast cancer, prostate cancer, kidney cancer, and some types of sarcomas. Different neuropeptides, particularly α-melanocyte-stimulating hormone (MSH), seem to play a role in the pathogenesis of melanoma. OBJECTIVE: We sought to analyze the expression of NPY in cutaneous melanoma, its association with clinical and histologic features, and its correlation with α-MSH. METHODS: This was an observational study of the immunohistochemical expression of NPY and α-MSH in tissue samples of cutaneous melanomas, different types of melanocytic nevi, and melanoma metastases diagnosed from 2004 to 2008 in San Jorge Hospital, Huesca, Spain. RESULTS: A total of 184 lesions were studied: 49 primary cutaneous melanomas, 12 melanoma metastases (9 cutaneous and 3 lymphatic), and 123 melanocytic nevi. Immunostaining revealed that levels of NPY and α-MSH were significantly higher in melanomas than in melanocytic nevi (P < .001). Melanoma metastases were negative for both neuropeptides. Nodular melanomas showed the highest median percentage of NPY positive cells (75% [20-95]) followed by superficial spreading melanoma (25% [2-92]), whereas lentigo maligna were negative (0% [0-0]). Significant, direct associations between NPY expression and vertical growth (P = .0141) and presence of metastasis (P = .0196) were observed. NPY and α-MSH were positively correlated in cutaneous melanoma (0.49, P < .001). LIMITATIONS: The sample size of melanomas was not very large. CONCLUSION: Our study demonstrates that NPY is significantly expressed in melanomas, especially the nodular type, being associated with invasiveness independently of proliferative markers such as thickness, ulceration, and mitotic index.
