es una queratina de bajo peso molecular presente en el epitelio glandular, y de todas las citoqueratinas disponibles, esta ha sido la que mejores resultados ha mostrado en el diagnostico de lesiones tiroideas.
In breast cancer, the mRNA expression of CEA, CK19
, CK20, GA733.2 and MUC 1 has been tested with variable results .
(4,10) Among cytokeratins, cytokeratin 7 (CK7), CK18, and CK19
are expressed, whereas CK14, CK17, and CK20 are not.
Negative markers include cytokeratins (CKs), such as CK3 and CK12 that are specifically expressed in the differentiated epithelium of the cornea and CK19
that is specifically expressed by the differentiated conjunctival epithelium [28, 29].
Immunohistochemistry was positive for TTF-1, thyroglobulin, CK19
, CK7, and EMA.
The lysate (2 [micro]L) was subjected to the automated reverse transcription loop-mediated isothermal amplification (RT-LAMP) of cytokeratin 19 (CK19
) mRNA using an RD-100i analyzer (Sysmex).
According to Sahoo et al (N=35, in New York), 93% of follicular variants of PTC and all cases of conventional PTC showed diffuse positivity for CK19
.  Studies by Debdas et al (N=22, in West Bengal, India) showed diffuse CK 19 staining in 84.5% of conventional PTC and 62.5% of follicular variants of PTC.
Schaub and coauthors  using cytokeratin-19 (CK19
) lineage tracing for LSPC progeny and high-efficiency hepatocyte marking demonstrated that, in the model of chronic liver injury caused by a special choline-deficient, ethionine-supplemented (CDE) diet regeneration did not involve LSPCs and all new hepatocytes stemmed from hepatocytes.
After 21 days, the expressions of albumin, AFP, CK18, CK19
, G6P, claudin, HNF4, and CYP2B6 mRNA were evaluated in the cells cultured on the 2D collagen films and in the 3D collagen scaffolds and compared to the control group.
Among epithelial markers, all HACs (100%) exhibited CK18 and CK19
stains, while only a small proportion (35.5%) of HAC patients showed positive stains for CK20 and CK7 which were predominantly detected in the poorly differentiated adenocarcinoma cells.
 isolated epithelial cells by laser capture microdissection and levels of CD21, CK19
, and EBV RNA were measured by quantitative reverse transcriptase PCR in oral dysplasia and squamous cell carcinoma.
In breast cancer, an mRNA encoding a CK (CK19
), has been the most frequently used in clinical studies (17); however, many transcripts (e.g., encoding CK18, CK19
, CK20, MUC1, prostate-specific antigen, and carcinoembryonic antigen) are also produced at low concentrations in normal blood and BM cells (17, 18).