ERBB2 and breast cancer: Similarly, compared to HER2+ breast cancer cases illustrated in Fig. 4, in which many of the tumor stromal vessels localized by CD34 immunoreactivity (a–d; right panels) were also VEGFR2+ (a–d; left panels), the TNBCs illustrated in Fig. 5, despite showing frequent localization of CD34+ tumor stromal vessels (a, b; right panels), only showed an occasional VEGFR2+ vessel in the tumor stroma (a, b; left panels, black arrows).