ID1 and neoplasm: Indeed, Id protein inactivation by delivery of a peptide-conjugated antisense oligonucleotide, by modulation of Id degradation by the proteasome or by expression of engineered HLH dimerization partner, has been shown to inhibit tumor growth, metastasis and angiogenesis (Chen et al. 2010; Ciarapica et al. 2009; Henke et al. 2008; Kuang et al. 2021; Mistry et al. 2013).