To identify genes that negatively or positively affect proliferation or survival of MYChigh tumor cells but not MYClow normal cells, we have performed a CRISPR genome-wide library screen in a tumor cell line (designated EC4) derived from a Tet system-regulated transgenic mouse model of MYC-induced HCC (LAP-tTA/tet-O-MYC/FVB/N)13. Here, MYC is linked to neoplasm.