ERBB2 and neoplasm: To determine if recognized epitopes were endogenously processed and presented by tumor cells, we re-stimulated individual peptide-expanded TILs with matched epithelial cell lines grown from the same patient tumor ascites samples, and observed stimulation of TILs specific for BIRC5, ERBB2, MAGEA12 and NY-ESO-1 epitopes by 2 patient-derived tumors (OV248 and OV436, Fig. 2b).