Some breast cancers are dependant on a specific cellular protein called “Her2” that turns on uncontrolled cell division. Trastuzumab is a targeted therapy that specifically turns off Her2 protein function. It revolutionized “Her2 + breast cancer” with significant improvement in survival and cure rates. It is so effective that now, research is showing that we can limit more toxic chemotherapy in Her2 positive breast cancer patients with small tumors by giving only one chemotherapy drug along with trastuzumab and still have a 98% survival rate. Any time we can lower toxicity and increase survival with targeted therapy is exciting for us.