ERBB2 and breast carcinoma: Examining Dock7 protein expression levels among a panel of 10 different breast cancer cell lines, half of which were HER2+, ER+/PR+/HER2+, or ER+/PR+ cell lines, while the remaining half were triple-negative breast cancer cell lines, also showed that triple-negative breast cancer cells exhibited higher Dock7 protein expression (Figure 2C).