Mucin-4 (MUC4)

May play a role in tumor progression. Ability to promote tumor growth may be mainly due to repression of apoptosis as opposed to proliferation.

Seems to change cellular behavior through both anti-adhesive effects on cell-cell and cell-extracellular matrix interactions and in its ability to function as an intramembrane ligand for ERBB2. Plays an essential role in cell proliferation and differentiation of epithelial cells by inducing specific phosphorylation of ERBB2.