ERBB3 and cancer: MM-121 is an erbB3 blocking Ab that is being actively investigated, mainly in combination with chemotherapy, in clinical trials of cancer patients with solid tumors, such as advanced non-small cell lung cancer, colorectal cancer, squamous cell head & neck cancer, platinum resistant/refractory ovarian cancer (http://www.clinicaltrials.gov/ct2/results?term=mm-121).