Detection of lymphatic invasion in early stage primary colorectal cancer with the monoclonal antibody D2-40

The purpose of this study was to investigate the presence of lymphatic invasion detected by D2-40 immunostaining compared to conventional hematoxylin-eosin (HE) staining in primary colorectal cancer (CRC) and the development of focal new lymphangiogenesis and peritumoral lymphatic proliferation in relation to the tumor stages. Additionally, we analyzed the relation of peritumoral inflammatory reaction (PIR) to tumor stages in CRC. The identification of new categories of patients with high-risk CRC would be very helpful in improving treatment strategies and patient outcome especially in early CRC.

Biopsies were taken from 41 patients with colorectal adenocarcinomas at different stages of disease. Immunohistochemistry was performed on paraffin-embedded sections. First, the whole section was screened for the presence of lymphatic invasion and PIR with routine HE staining. After analysis of the HE-stained slides, the slides were destained and reused for immunohistochemistry with the D2-40 monoclonal antibody. D2-40-immunostained sections were screened for the presence of lymphatic invasion, the proliferation of lymphatic vessels and focally newly developed lymph vessels.

Using the D2-40 antibody for immunostaining, our results demonstrate a significantly higher detection (p < 0.05) of lymphatic vessel invasion compared to routine HE staining in primary CRC. 22% more patients with lymphatic vessel invasion could be identified compared to routine HE staining, especially in node-negative tumor stage (UICC II). The positive predictive value of lymphatic invasion evaluated by D2-40 immunostaining to predict lymph node metastasis is 92% (negative predictive value 81%). High PIR was shown in UICC stage I and II. These infiltrations were rarely seen in UICC stage III and were absent in UICC stage IV. Higher UICC tumor stage is associated with a higher rate of focally newly developed lymphatic vessels. In UICC stage I we found peritumoral lymphatic vessel proliferation only in one case (14%) and in UICC stage II no case was found. 47% of the cases in UICC stage III and 50% of the cases in UICC stage IV showed focal peritumoral lymphatic vessel proliferation.

Immunostaining with D2-40 significantly increased the detection rate of lymphatic invasion compared to conventional HE staining in primary CRC. The D2-40 antibody specific for lymphatic endothelium cells has the potential for a prognostic marker in early stage CRC. Further prospective studies are necessary to evaluate the prognostic value of lymphatic invasion and the induction of tumor lymphangiogenesis and its role in human cancer progression.