ERBB2 and cancer: This involved co-culturing T cells expressing the putative TCR with three different cancer cell lines expressing the antigen of interest at different levels: SK-MEL-5, which shows high HER2/neu expression levels (HER2/neu+++); HCT-116, which displays moderate HER2/neu expression levels (HER2/neu+); and MDA-MB-231, with minimal HER2/neu expression in a small subset of cells (HER2/neu+/−).