KRT19 and neoplasm: CK19 is a membrane protein expressed by most breast carcinomas even after NAST, constituting a good target to detect BC metastasis [10, 11].The calculation of the total tumor load (TTL) based on CK19 mRNA copy number is a highly sensitive and specific method for the detection of micro and macrometastasis of lymph nodes (LNs) [12, 13].