For instance, in a cohort of 57 patients with matched breast cancer and lung or pleural metastasis (BCLM), Klebe et al. reported that out of 28 patients initially diagnosed as luminal A breast tumor (PAM50), 10 recurred as luminal B and four recurred as ERBB2-enriched lung metastasis 3. Here, ERBB2 is linked to metastasis.