Histochem Cell Biol (2011) 135:581–591 587 Fig. 4 Pairs of serial sections stained for immunohistochemical detection of E-Cadherin (left panels, a, c, e, g) or DPPIV enzyme activity (right panels, b, d, f, h). c, d, g, h Magniﬁcations of a, b, e, f, respectively. While E-cadherin expression was regularly found (punctuated dark blue dots, arrows) in clusters of transplanted normal hepatocytes (compare a vs. b and c vs. d, dotted lines), immunostaining in nodular hepatocyte clusters was virtually undetected (compare e vs. f and g vs. h), while arrows in g indicate punctuated expression of the protein in the liver surrounding nodular hepatocytes. See ‘‘Materials and methods’’ for details was found at the ill-deﬁned boundary between clusters of normal transplanted hepatocytes and the surrounding host liver (Fig. 5a–c), in agreement with previous ﬁndings (Koenig et al. 2005). In addition, scattered MMP-2 activity could also be detected within these clusters (Fig. 5g). On the other hand, a sharp demarcation was readily apparent between clusters of transplanted nodular hepatocytes and the positive immunostaining for MMP-2 (Fig. 5d–f). While the protein was strongly expressed in the tissue surrounding nodular lesions, MMP-2 activity was virtually absent within nodular hepatocyte clusters (Fig. 5h). Furthermore, we found that the expression of MMP-2 RNA was markedly decreased in nodular hepatocyte prep- arations as compared to their normal counterparts (Fig. 6). 123