In canine mammary cancer (CMC), changes in the expression of many genes and protein levels, such as epidermal growth factor receptor (EGFR), phosphatase and tensin homolog (PTEN), and TWIST, have been reported (Beirão et al., 2015; Qiu et al., 2008; Silva et al., 2014). The gene discussed is EGFR; the disease is breast cancer.