Anyhow, the science. Cells multiply when stimulated by some signaling molecule (ligand) which attaches itself to its ligand-specific receptor. Some cells have too many genes that encode for the receptor (in this case HER2) and so we end up with 200,000 copies of the receptor protein embedded in the outer membrane as opposed to the normal 10,000. So now when a growth signaling ligand winds up near the cell all sorts of bad things happen and the cells divide much more than they should resulting in cancer. 25-30% of breast cancers show HER2 over expression. The biologists have confirmed and documented that HER2 over expression can cause cancer, but on its own cannot.
The paper that we are reproducing as part of the Summer Research experience: brought to you by the Math department, its about the quantitative effect of HER2 over expression on cell growth. i.e if you have these many receptors you will have this much increased cell growth. And so continues the translation of Biology into Math.