D2-40 (Podoplanin)

D2‑40 is a monoclonal antibody that detects podoplanin, a 40 kDa transmembrane glycoprotein normally found in lymphatic endothelium, mesothelium, and fetal testis. Podoplanin is encoded by the PDPN gene (1p36.21) and its expression is regulated by PROX1. D2‑40 shows membranous staining and is mainly used to highlight lymphatic vessels, helping identify lymphovascular invasion and lymphatic differentiation in vascular tumours. It is also helpful as part of an IHC panel when distinguishing mesothelioma from adenocarcinoma and seminoma from non-seminomatous tumours (1).

Recommended Controls

Criteria for acceptable staining is a membranous and cytoplasmic staining pattern. The recommended positive controls to use include known mesothelioma, tonsil, SCC of the skin and appendix. Mesothelioma will be strongly positive in the tumour cells as well as in the normal mesothelium. Tonsil will be positive only in the endothelial cells and the follicular dendritic cells while the appendix can be used as both a positive and negative control (with moderate cytoplasmic staining of the Schwann cells and strong membranous staining of lymphatic endothelial cells).

Expected staining pattern

Endothelial cells

Mesothelioma

Disclaimer

These methods are intended as a guide only. Laboratories that wish to implement these methods should perform internal validation/verification prior to use. The RCPAQAP does not make any claim or warranty for the accuracy or performance of these methods.