SPARC and breast cancer: Here we show that a subgroup of just three of the 18 genes: collagen XIII, alpha 1 (Col13a1), secreted frizzled-related protein 1 (Sfrp1), and sparc/osteonectin, cwcv and kazal-like domains proteoglycan (testican) 2 (Spock2), was able to stratify a previously described canine mammary cancer cohort of 27 ERneg patients [19] into groups of mammary tumours with Metpos and Metneg status, and hence poor or good survival over 24 months.