SPARC and breast cancer: Importantly, SPARC peptides corresponding to the 27-kDa (207 - 218), 16-kDa (179 - 191), 9-kDa (236 - 256), and 6-kDa (258 - 268) fragments have been found in BC samples by using an on line proteomic database (https://cptac-data-portal.georgetown.edu/) 62.