Figure 4

Endothelial cells within HCC recurrences in patients who received sex-mismatched liver allografts originate from the donor allograft rather than from tumor cells. A) Representative immunofluorescence staining for CD31 (red) and CD45 (green) identifies ECs (red arrows) and leukocytes (green arrows) within an HCC recurrence that arose in a male patient who received a liver allograft from a female donor (x400). B) Fluorescence in situ hybridization (FISH) overlay image of field corresponding to that shown in Panel A demonstrating that nuclei of endothelial cells (red arrows) have only X chromosomes (red dots) while leukocytes (green arrows) and tumor cells have both X chromosomes and Y chromosomes (green dots) (x400). C) Representative immunofluorescence staining for CD34 (green) identifies sinuisoidal ECs (arrows) within a recurrent HCC (x400). D) FISH overlay image of a field corresponding to that shown in Panel C demonstrating that endothelial cell nuclei (arrows) have only X chromosomes (red dots) while surrounding tumor cells have both X chromosomes and Y chromosomes (green dots) (x400). The XY phenotype of the tumor cells also confirms that the HCCs occurring in the liver allografts are recurrences of the male patient’s original tumor (XY) rather than malignancies arising from de novo transformation of hepatocytes in the XX liver allograft.