For example, Aurilio et al. demonstrated that in 92% of breast cancer patients, the HER2 status was similar in the primary breast tumor and its paired bone metastases [57], whereas Rack et al. reported that in approximately 69% of patients, the HER2 status of the primary tumors correlated with the HER2 status of the disseminated tumor cells collected from the bone marrow [58]. The gene discussed is ERBB2; the disease is breast cancer.