CD44 and hepatocellular carcinoma: Due to AKT1/luciferase gene transposition, the HCC clones exhibited bioluminescent reporter gene activity (Figure 1E), as well as higher levels of MHC class I protein (H-2Kb, Figure 1F) and the cancer stem cell (CSC) marker CD44 (Figure 1G) compared to Hepa1-6 cells.