On a regulatory level, activation of E2F1 (E2a binding factor-transcription factor 1 [226]), a transcription factor that regulates cell cycle progression, or knockdown of SRBD1 (S1 RNA binding domain 1), an RNA-binding protein overexpressed in non-small cell lung carcinoma, both reduced A0 protein abundance, and resulted in increased sensitization to apoptosis, slowed proliferation in tissue culture, and reduced tumour sizes in animal models [227,228]. This evidence concerns the gene SRBD1 and neoplasm.