SK-Hep1 cells with overexpressed E2F1 or ISX showed increased transformation (by 42% and 86%, respectively) and oncogenic activity (by 71% and 153%, respectively), whereas E2F1 or ISX-knockdown SK-Hep1 cells displayed decreased transformation (by 44% and 70%, respectively) and oncogenic activities (by 92% and 98%, respectively), as determined by soft agar anchorage-independent foci formation in vitro and tumor growth in nude mice in vivo (Figure 5C and 5D). Here, E2F1 is linked to neoplasm.