Thus, to overcome this problem, and since the cat is a good cancer model [58], the antiproliferative effects of two anti-HER2 mAbs (trastuzumab and pertuzumab) and one ADC (T-DM1) were evaluated, using a FMC cell-based model (CAT-MT, FMCm and FMCp cell lines), presenting different HER2 expression levels, and with no mutations described as conducing to resistance to therapy (Table S3). The gene discussed is ERBB2; the disease is cancer.