MMP9 and neoplasm: Double immunofluorescence analysis showed that a subpopulation of CD30+ cells overexpressed TGFβ1 and MMP9 (Figure 4B and 4C), suggesting that CD30+/TGFβ1+ and CD30+/MMP9+ cells may potentiate a metastatic environment that allows CD30+ HL tumor cells to exit the local tumor microenvironment.