Mucins are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by many epithelial tissues in vertebrates. DS-MB-01935 recognizes CD227, also known as mucin 1 which is a breast cancer associated mucin encoded by the Muc-1 gene. CD227 is expressed on most secretory epithelium, including mammary gland and some hematopoietic cells. This protein is overexpressed abundantly in >90% breast carcinomas and metastases. The dominant epitope recognized by this antibody is the 12-mer GVTSAPDTRPAP of the mucin 1 tandem repeat. DS-MB-01935 has been tested on frozen human ovarian carcinoma tissue sections and paraffin embedded sections from normal breast tissue. This antibody also reacts weakly with sections of small intestine and colon.