One study is testing the E75 plus GM-CSF vaccine in combination with trastuzumab in patients with high-risk, HER2 IHC 3+ BC [104] and the other one is evaluating the same combination with trastuzumab in patients with HER2 low-expressing tumors (IHC 1+ or 2+) [120]. This evidence concerns the gene CSF2 and breast cancer.