Fig. 4. Prox1 is a marker of the lymphatic vasculature in adult tissues. (A, C and E) Prox1 is expressed in the superficial lymphatic vessels located in normal adult tissues (arrowheads), and in the lymphatic vasculature surrounding (C) or inside (E) a squamous cell carcinoma (arrow). The co-expression of Prox1 and VEGFR-3 (B), SLC (D) and LYVE-1 (F) in adjacent sections confirmed the lymphatic-specific nature of Prox1-positive vessels. Red arrowheads in (B) indicate intratumoral VEGFR-3-positive blood vessels located inside the tumor. Scale bar: 100 µm.