Figure 1. Distinctive features of cancer cell phenotypes of the four models of experimental malignant mesotheliomas.

(A and B): Hematoxylin-phloxine-saffron (HPS) staining (respectively low and high magnification); (C): Immunohistochemical detection of the Ki67 antigen (proliferation index). The four models displayed distinctive characteristics: the M5-T2 tumors are located strictly on the omental serosal surface (asterisk: connective adipose tissue and composed of monomorphic neoplastic cells with moderate atypias and low proliferative activity (C: low number of immunopositive nuclei); the F4-T2 and F5-T1 neoplasms are characterized by increased infiltrative potential with invasion of the deep muscular layers (diaphragm and abdominal wall: asterisk) and are composed of cells with marked atypias and very high ki67 index of proliferation (C: high number of immunopositive nuclei); the M5-T1 tumors are associated with deep infiltration of abdominal organs (liver parenchyma on the picture: asterisk), marked atypias and moderate to high proliferation (C: intermediate number of immunopositive nuclei).