As ancillary tests, the following immunohistochemical stains are used: CD34 (+), CD31 (diffuse, weak + [180], can be explained by the increased degradation of PECAM [140]), ERG (+), D2-40/podoplanin (+), PROX1 (+), FLI1 (+) and nuclear HHV8 (LANA 1—which is essentially almost always positive in KS and negative in other proliferations of a vascular nature) [181]. This evidence concerns the gene PDPN and Kaposi's sarcoma.