GNB4 and breast cancer: In another study, circRREB1, a novel circRNA that is upregulated in BC, was identified to promote increased tumor growth and metastasis through extracellular signal-regulated kinase 1/2 (Erk 1/2) signaling pathway by interaction with GNB4 and is associated with poor prognosis in BC patients (H. Chen et al. 2024a, b).