Immunohistochemistry assay with EGFR L858R was positive in 19 (86%) of the HER2-positive breast carcinomas and negative in all HER2-negative carcinomas.
In conclusion, using G129R-based fusion proteins to target mammary carcinomas and to tackle multiple hallmarks of cancer at the same time was an effective strategy for treating HER2-postive mammary cancer in this mouse tumor model.