Propranolol treatment also reduces the expression of pro-proliferative Ki67 in the early stage of breast cancer, decreases phosphorylation of p44/42 MAPK, p38 MAPK, c-Jun N-terminal kinase (JNK) and CREB in mitogenic signaling, elevates phosphorylation of cell survival/apoptosis regulators AKT, p53 and glycogen synthase kinase 3β (GSK3β) in SK-BR-3 breast cancer cell line, leading to induction of apoptosis and suppressed tumor proliferation [141]. Here, CREB1 is linked to breast cancer.