Stromal expression of vascular endothelial growth factor C is relevant to predict sentinel lymph node status in melanomas

The dissemination of tumour cells to the lymph nodes is a complex process involving the formation of new lymph vessels, or lymphangiogenesis, produced by the tumour itself. The main growth factor involved in lymphangiogenesis is vascular endothelial growth factor C (VEGF-C), which is secreted by several different malignant tumours, including melanoma. Not only has VEGF-C expression been found in tumour cells, it has also been detected in tumour stromal cells like macrophages and fibroblasts. This study aimed to determine whether the expression of VEGF-C in tumour and stromal cells in cutaneous melanoma determines lymphangiogenesis and neoplastic dissemination to lymph nodes. We examined cases from 50 patients with melanoma who underwent selective biopsy of the sentinel lymph node. Immunohistochemical study was done with D2-40 to label lymph vessels, and the expression of VEGF-C was evaluated in tumour and stromal cells. Lymph vessel density was greater in sentinel lymph node-positive than in sentinel lymph node-negative cases, though the difference was not significant (P = 0.075). A significant correlation was seen between lymph vessel density and tumour thickness and the presence of ulceration. The main finding was that the expression of VEGF-C in fibroblasts was highly associated with the presence of metastasis in the sentinel node and with the Clark level. However, VEGF-C expression showed no relation in either tumour cells or macrophages with node status or other prognostic factors, such as the Breslow index or Clark level. Our results highlight the relevance of the stroma in tumour progression in cutaneous melanoma and its role in the spread to lymph nodes.