Anti-Keratin 19: Mouse Keratin 19 Antibody

There are two types of Cytokeratins. Type I (9–20) Cytokeratins are relatively acidic and are of small molecular weight (40–56.5 kDa). Type II (1–8) Cytokeratins are relatively basic-neutral and of larger molecular weight (53–67 kDa). Expression of CK in epithelia is dependent on types (simple or stratified), and differentiation pattern of epithelia. CK can be subdivided into markers of cornification (CK 1, 2, 10, and 11), stratification (CK4, 13), basal cells (CK 5, 14, 15, and 17), simple cells (CK 7, 8, 18, and 19), and hyperproliferation (CK6, 16). Although CKs are expressed in specific combinations in different epithelia, the number of permutations is limited, and thus insufficient to endow every epithelium with its own unique CK profile.¹

Cytokeratin 19 is a type I cytokeratin. Unlike its related family members, this smallest known acidic cytokeratin is not paired with a basic cytokeratin in epithelial cells. It is specifically found in the periderm, the transiently superficial layer that envelops the developing epidermis. CK19 is often used together with CK8 and CK18 to differentiate cells of epithelial origin from hematopoietic cells in tests that enumerate circulating tumor cells in blood.² CK19 is stably and abundantly expressed in epithelial tumors, but not in mesenchymal hemopoietic cells, and has been successfully used as a marker for the detection of tumor cells in the bone marrow, lymph nodes, and peripheral blood by immunohistochemistry and RT-PCR.³