Tumor markers cytokeratins

Buccheri G, Ferrigno D. Lung tumor markers of cytokeratin origin an overview. Lung Cancer 2001 34 S65-S69. 

Moch H, Kononen J, Kallioniemi OP, Sauter G (2001) Tissue microarrays what will they bring to molecular and anatomic pathology Adv Anat Pathol 8 14 20 Moll R (1998) Cytokeratins as markers of differentiation in the diagnosis of epithelial tumors. Subcell Biochem 31 205 262... 

Typical ES/PNET is nonreactive for chromogranin, cytokeratin, glial fibrillary protein, desmin, muscle-specific actin, myogenin, CD31, and However, in studies of tumors that were confirmed by molecular identification of the t(ll 22) translocation, immunoreactivity for cytokeratin has been present in 20% to 30% of ES/PNET cases.Nonetheless, in our experience, keratin has been relatively focally expressed in these tumors when present. NB84 (a marker developed for recognition of neuroblastoma) is also apparent in roughly 20% of ES/PNETs. 

S-100 protein is not diffuse in MCS. It is limited to the chondroblastic islands of that tumor and is lacking in the small cell component. All elements potentially label for CD57, and most cases are also reactive for NSE. Factor Xnia has been documented in MCS as well, but that marker is non-specific.Tumors of this type arising in the central nervous system are alleged to show cytokeratin and GFAP reactivity in 25% of cases,but we are dubious of that contention based on our experience. 

Moll R. Cytokeratins in the histological diagnosis of malignant tumors. Int J Biol Markers. 1994 9 63-69. 

The tumor cells are positive for neuroendocrine markers, and up to 30% can be positive for cytokeratin. 

The tumors are positive for synaptophysin, chromogranin, and neuron-specific enolase and may express a variety of hormones (growth hormone, prolactin, TSH, ACTH, and FSH). A few are hormone negative and are designated as null-cell adenomas. Almost all are positive for CAM 5.2, either focally or diffusely, and about half are positive for AE 1/3. They are negative for cytokeratin 7, 19, and 20, as well as S-100 protein. Pituitary transcription factor-1 is selectively expressed in tumors that express growth hormone, prolactin, and TSH. No diagnostic molecular markers are currently in use for sporadic pituitary lesions. ... 

The immunophenotype of these tumors includes positivity for neuroendocrine markers and for cytokeratins. 

These tumors can occasionally undergo dedifferentiation in a similar manner to adenoid cystic carcinoma. On immunostaining, the ductal cells are strongly positive for cytokeratins such as AEl-3 and CAM5.2. The myoepithelial component is usually strongly positive for typical myoepithelial cell markers such as p63, SMA, and calponin (see Table 9.13, Figs. 9.23 and 9.24). 

FIGURE 10.38 Distribution of markers in pancreatic endocrine tumors. SYN, synaptophysin NSE, neuron-specific enolase LMWCK, low-molecular-weight cytokeratin CgA, chromogranin A PC2, pro-convertase 2 PCM, peptidylglycine alpha-amidating enzyme PC3, proconvertase 3 NFP, neurofilament protein HCC(a), human chorionic gonadotropin alpha VIM, vimentin. 

Carcinoids, atypical carcinoids, small cell carcinomas, and large cell NE carcinomas have been reported as primary cervical tumors.All small cell cervical carcinomas studied to date have been cytokeratin-positive, and more than 90% have been positive for EMA. Reactivity for CEA with polyclonal antisera occurs in 77%. Small cell cervical carcinomas are positive for CK20 or TTF-1 in 14.3% and 20% of cases, respectivelyWith respect to NE markers, NSE is present in 95%, synaptophysin in 46%, chromogranin A in 43%, and CD57 in 37%. Similar frequencies of positivity for NE markers have been reported in more recent studies.These tumors may also contain peptide and amine hormones including serotonin (31%), ACTH (23%), and somatostatin (8%). 

Most sarcomatoid mesotheliomas express keratin (usually low molecular weight keratin), vimentin, and frequently muscle-specihc/alpha actin. In our experience, a relatively small percent (10% to 20%) of sarcomatoid mesotheliomas express calretinin, and most sarcomatoid mesotheliomas do not express cytokeratin 5/6. Most sarcomatoid mesotheliomas express CK7, often intensely. In our experience, sarcomatoid mesotheliomas (and tumors with which they may be confused) do not express the negative markers used to evaluate potential epithelial mesotheliomas, including CEA, LeuMl, B72.3, BerEP4, BG8, and TTF-1. Therefore, we would not include these antibodies in a screen of a malignant spindle cell proliferative lesion of the pleura. 

Moll R. Cytokeratins as markers of differentiation in the diagnosis of epithelial tumors. Subcell Biochem. 1998 31 205-262. 

Cytokeratins (CKs) are a family of intracytoplasmic intermediate filament proteins present in almost all epithelia. Expression of each CK molecule depends on cell type and differentiation status, and therefore specific CKs can be used as markers to identify particular types of epithelial tumors (Table 16.5). CK7 is found in a wide variety of epithelia including the columnar and glandular epithelium of the lung, cervix, and breast, as well as in the bile duct, collecting ducts of the kidney, urothelium, and mesothelium, but not in most gastrointestinal epithelium, hepatocytes, proximal and distal tubules of the kidney, and squamous epithelium. In contrast, CK20 shows relatively restricted expression and is present in gastrointestinal epithelium, Merkel cells of the epidermis, and urothelium. 

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