Using MDA-MB-231 breast cancer cells, we were able to detect extracellular proteolytic cleavages of ectodomains of membrane-anchored proteins in both physiological and slightly acidic pH environments, showing that apoptotic caspases-3 and -7 can be recognized as a part of the proteolytic network in the case of TNBC. Here, CASP3 is linked to breast carcinoma.