While, De Maria and colleagues [15] reported that ERBB2 is overexpressed in mostly feline mammary lesions, suggesting that FMT is a good model for ERBB2 overexpressing breast tumors with poor prognosis, Soares and co-authors [14] showed that ERBB2 is overexpressed in about 33% of FMTs also indicating that is a suitable model to study ERBB2 positive breast cancers without gene amplification. The gene discussed is ERBB2; the disease is breast neoplasm.