Fig. 1

Stroma characteristics of KAT-4, CT-26 and B16BB tumors. KAT-4, CT-26 and B16/BB tumor sections were stained with antibodies directed against CD31 (A–F brown), ASMA (A, C, E blue) or PDGFRβ (B, D, F blue). CD31-positive structures are indicated asterisk and perivascular staining of ASMA and PDGFRβ is indicated by black arrows. Collagen fibers were stained by Sirius red (G–I). The bars represent 100 μm. Average hydroxyproline levels in whole tumors (J)