[Lani]

1) As I understand it, mice do not get ER+ breast tumors (only if human ER+ breast cancer cells are implanted in them) so this article wouldn't be able to show what you are asking ie, whether the tumors would be herw+ER+ or her2+ ER-. neu transgenic Mice only get ER- her2+ tumors.

2)you are confusing fats (good/bad) with fatty acids which are the building blocks of fats

Cancer cells grow faster than other cells and fatty acids are necessary to build cell membranes. So a shortage of the ingredients slows things down. Once the cancer was present however, it did not stop the cancer from growing (cancer figures out all sorts of ways around things like "eating itself or nearby cells "
to provide the fatty acids and other building blocks to grow

hope this helped