Purity: > 90% by SDS - PAGE Format: Liquid. In 20mM Tris-HCl buffer (pH 8.0) containing 0.4M urea, 10% glycerol . Prolactin-inducible protein, also known as PIP, is a major protein component of benign breast gross cysts. It is a known marker of breast cancer, as it is found in approximately 50% of all breast cancer specimens. It is expressed in exocrine glands and, in pathologic conditions, in breast cysts and breast cancers exhibiting apocrine features. PIP and prostate specific antigen are co-expressed in androgen receptor-positive breast tumours. Recombinant human PIP protein, fused to His-tag at N-terminus, was expressed in E.coli.