Paraffin-embeedded specimens were retrospectively selected and evaluated regarding their histopathology, tumor grade, lymph node status and additional sections from each case were immunostained with anti-D2-40 monoclonal antibodies (Dako Cytomation, Carpinteria, CA, USA) to highlight lymphatic vessels and D2-40 expressing tumor cells.
Incubation with primary antibody was followed by the use of labeled streptavidin biotin working system (LSAB , Dako Cytomation) and 3,3’ diaminobenzidine as chromogen.
Podoplanin is involved in tumorigenesis and cancer progression in head and neck malignancies and its expression is not restricted to lymphatic vessel endothelium (2).
Lymphatic vessels (LVs) identified with anti-podoplanin antibodies have been demonstrated in tumoral and peri-tumoral areas, and their number correlates with prognosis in malignant melanomas (3), squamous cell carcinomas of the head and neck (4, 5), breast cancers (6) and gastric adenocarcinomas (7).
Known as a lymphatic endothelial marker, podoplanin has been found to be overexpressed in tumor cells of various cancers with a certified involvement in tumor progression, invasion and metastasis.
Lymph vessels were identified both in the peritumoral area and intratumoral area among cords and clusters of malignant cells.
In the peritumoral area they constantly had a wider lumen and a slightly irregular contour (Figure 1b).
The lymphatic endothelium was homogenously stained, with high intensity, this aspect facilitating the recognition of these structures.
D2-40 expression was positive in LVs and did not stain the endothelium of blood vessels (Figure 1a).