KRT19 (Cytokeratin 19) is known to be the smallest (40 kDa) member of the acidic type I cytokeratin family proteins (KRTs) and may play a potential role in tumor detection by reverse transcriptase polymerase chain reaction (RT-PCR) in the bone marrow, lymph nodes, and peripheral blood of patients with breast cancer [31,32]. This evidence concerns the gene KRT19 and breast cancer.