CUL1 and neoplasm: To investigate if the degradation of HPV16 E7 protein by CUL1 and UBE2L3 inhibits tumor growth, we utilized a C57BL/6J (B6) mouse oral epithelial (MOE) cell line expressing HPV16 E6/E7 and Hras (mEERL) which forms tumors in immunocompetent syngeneic B6 mice (34).