[Isoform 1]: Cell membrane ; Lipid-anchor, GPI-anchor . Endoplasmic reticulum . Mainly found intracellularly. .; [Isoform 2]: Secreted .
Isoform 1 is highly expressed in colon and in a number of tumor cell lines and highly restricted in normal tissues. Both isoforms are frequently expressed in cell lines derived from epithelial cancers, and in primary breast cancers.