CK7 is an intermediate filament with a selective expression pattern in different carcinomas, which when combined with CD20 is useful in the work up of carcinomas of unknown primary origin.
Common expression patterns in carcinoma (Dennis, JL, et al).
|
Tumor
|
Expression %
|
|
Breast
|
>80%
|
|
Colon
|
<10%
|
|
Lung
|
>90%
|
|
Ovary
|
>80%
|
|
Pancreas
|
>80%
|
|
Stomach
|
35-70%
|
|
Prostate
|
~10%
|
Moll, RT, et al. Cytokeratin expression in various tumors.
|
Tumor
|
CK8/CK18
|
CK19
|
CK7
|
CK20
|
CK5
|
|
Hepatocellular Ca.
|
+
|
+/-
|
+/-
|
+/-
|
=
|
|
Colorectal ACA
|
+
|
+
|
+/-
|
+
|
=
|
|
Stomach ACA
|
+
|
+
|
+/-
|
+/-
|
=
|
|
Pancreas Ductal ACA
|
+
|
+
|
+
|
+/-
|
+/-
|
|
Lung ACA
|
+
|
+
|
+
|
=
|
=
|
|
Breast Inv. Ductal
|
+
|
+
|
+
|
=
|
+/-
|
|
Endometrium ACA
|
+
|
+
|
+
|
=
|
+/-
|
|
Ovary ACA
|
+
|
+
|
+
|
=
|
=
|
|
RCC, Clear Cell Type
|
+
|
+/-
|
=
|
=
|
=
|
|
RCC, Papillary Type
|
+
|
+
|
+
|
=
|
=
|
|
RCC, Chromophobe
|
+
|
+/-
|
+
|
=
|
=
|
|
Mesothelioma
|
+
|
+
|
+/-
|
=
|
+
|
|
Lung, Small Cell Ca.
|
+
|
+/-
|
=
|
=
|
=
|
|
Merkel Cell Ca.
|
+
|
+
|
=
|
+
|
=
|
|
Urothelial Carcinoma
|
+
|
+
|
+
|
+/-
|
+/-
|
|
Squamous Cell Ca.
|
+/-
|
+/-
|
=
|
=
|
+
|
Key: “+/-“, focal staining in some cases. “=“, negative, “+”, positive.
Photomicrographs
References
Hadi, AIMM Annual Meeting, “The Thirty Most Important Antibodies”, presentation, 2011.
Dennis, J. L., Hvidsten, T. R., Wit, E. C., Komorowski, J., Bell, A. K., Downie, I., et al. (2005). Markers of adenocarcinoma characteristic of the site of origin: development of a diagnostic algorithm. Clinical Cancer Research : an Official Journal of the American Association for Cancer Research, 11(10), 3766–3772. doi:10.1158/1078-0432.CCR-04-2236
Moll, R., Divo, M., & Langbein, L. (2008). The human keratins: biology and pathology. Histochemistry and Cell Biology, 129(6), 705–733. doi:10.1007/s00418-008-0435-6