PECAM1 and hepatocellular carcinoma: Furthermore, forced expression of MAT1A in human HCC cells was found to suppress in vivo tumorigenicity in mice [91] and Huh7 cell transfectants, stably overexpressing MAT1A, and showing higher SAM levels, lower HCC growth rates, microvessel density, CD31 and Ki-67 staining, and higher apoptosis with respect to control tumors [91].