Several cases of pancreas, colorectal, ovarian and stomach cancers along with occasional urothelial cancers showed weak to moderate cytoplasmic and membranous staining. Rare cases of breast and cervix cancers displayed moderate to strong cytoplasmic positivity. Remaining cancers were weakly stained or negative.
Moderate to strong cytoplasmic immunoreactivity was observed in cancer tissues. Additional membranous staining was exhibited in few colorectal and liver cancers.
ABCB4 (HGNC Symbol)
ABCB4, GBD1, MDR2, MDR3 , PFIC-3, PGY3
ATP-binding cassette, sub-family B (MDR/TAP), member 4 (HGNC Symbol)
Entrez gene summary
The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance as well as antigen presentation. This gene encodes a full transporter and member of the p-glycoprotein family of membrane proteins with phosphatidylcholine as its substrate. The function of this protein has not yet been determined; however, it may involve transport of phospholipids from liver hepatocytes into bile. Alternative splicing of this gene results in several products of undetermined function. [provided by RefSeq, Jul 2008]