NOTCH2 and pulmonary fibrosis: MK activates the Notch2 signaling pathway, up-regulates the downstream target HES1 and promotes tumor cell proliferation while inhibiting tumor cell apoptosis (Kishida et al., 2013) Notch signaling has been found to be upregulated in pulmonary fibrosis, and inhibition of Notch significantly alleviated pulmonary fibrosis.