D2-40, a novel lymphatic endothelial marker: identification of lymphovascular invasion and relationship with axillary metastases in breast cancer

Background: Studies of lymphatic vessels were limited by the lack of specific markers. Recently, they have become possible due to the release of new D2-40 antibody, a selective marker for lymphatic endothelium. The aim of our study was to compare neoplastic invasion in lymphatic and blood vessels detected in hematoxylin and eosin (H&E) and immunohistochemistry-stained sections. Methodology: A total of 123 cases of invasive mammary carcinomas were studied and sorted out into three subgroups according to axillary staging (macrometastasis, micrometastasis and lymph node negative). Lymphatic vessel invasion (LVI) and blood vessel invasion (BVI) were initially evaluated in histological H&E and immunohistochemistry-stained sequential sections. Lymphatic and blood vessel invasions were assessed by immunohistochemistry, employing D2-40 and CD31 antibodies, respectively. LVI and BVI were related to size, type, histologic grade of primary tumors, and the presence of metastasis. Results: LVI was detected through H&E staining procedure in 17/123 cases (13.8%), and through immunohistochemistry procedure in 35/123 cases (28.5%) (kappa = 0.433). BVI was detected through H&E in 5/123 cases (4.1%), and through immunohistochemistry in 19/123 cases (15.4%) (kappa = 0.198). LVI and BVI were positively related to higher histologic grade of primary tumors (p < 0.05). LVI was also positively related to the presence of macrometastasis. Conclusion: The detection of lymphatic and blood vessel invasions through immunohistochemistry employing D2-40 and CD31 was higher than the detection through H&E, and it was related to higher tumor grade and metastasis in axillary lymph nodes.