TTR and breast cancer: A unique combination of serum biomarkers for BC and the confirmation of this panel of biomarkers as an independent sample set has been performed by SELDI-TOF MS technique, while MALDI-TOF/TOF MS analysis was useful for the identification of these biomarkers, such as apolipoproteins (APOH, APOCI, APOI), C3a-desArg, and transthyretin (TTR) [49].