**Background of KRT19 Antibody**
Keratin 19 (KRT19), a 40 kDa type I intermediate filament protein, is a member of the keratin family, which forms structural networks in epithelial cells. It is predominantly expressed in simple and glandular epithelia, such as those in the liver, pancreas, and breast ducts, and is absent in stratified squamous epithelia. KRT19 plays a role in maintaining cell integrity, signaling, and stress response.
KRT19 antibodies are widely used as biomarkers in research and diagnostics. In cancer studies, KRT19 is a key marker for identifying epithelial-derived tumors, including carcinomas of the breast, lung, and gastrointestinal tract. It is crucial in detecting circulating tumor cells (CTCs) and micrometastases, aiding in prognosis and treatment monitoring. However, its expression in some non-epithelial cells (e.g., activated hepatic stellate cells) necessitates careful interpretation to avoid false positives.
Clinically, KRT19 antibodies are employed in immunohistochemistry (IHC) to differentiate carcinomas from sarcomas or melanomas. Variants like clone BA17 or RCK108 are validated for specificity in assays such as Western blotting (WB) and immunofluorescence (IF). Despite its utility, variable expression levels across tumor subtypes and technical factors (e.g., antibody clones, fixation methods) highlight the need for standardized protocols. Overall, KRT19 antibodies remain vital tools in understanding epithelial biology and advancing cancer diagnostics.