Nestin, prominin-1, CK5, and SMA was more often expressed in the primary breast tumor when the first metastases were found in the brain compared with other first metastatic sites (3 (15.8%) of 19 vs. 7 (3.7%) of 187, P = 0.053; 3 (20.0%) of 15 vs. 6 (3.6%) of 165, P = 0.029; 4 (19.0%) of 21 vs. 7 (3.8%) of 186, P = 0.016; and 2 (22.2%) of 9 vs. 9 (4.3%) of 210, P = 0.068, respectively). The gene discussed is PROM1; the disease is breast neoplasm.