CAM5.2

CAM5.2 is an antibody clone manufactured by Becton Dickinson (BD), which shows reactivity to CK8 primarily and CK7 to a less extent. It does not demonstrate reactivity to CK18 or CK19. Sometimes CAM5.2 has been used interchangeably with CK8/18 in the medical literature, which is not correct (Hsu, JD, et al). It is an excellent screening marker for poorly differentiated carcinomas, micro-metastasis of carcinoma in lymph nodes, and for characteristic peri-nuclear dot-like reactivity in Merkel cell carcinoma.

AE1/AE3 is generally the most common screening cytokeratin marker used, which has both high and low molecular weight cytokeratins. Rarely AE1/AE3 may not stain a poorly differentiated carcinoma, which will mark with CAM5.2.

CAM5.2 may occasionally stain myofibroblasts and smooth muscle cells, which may express cytokeratins in certain situations (Moll, RT, et al).

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.

Microscopic Images

CAM5.2 - Colon Adenocarcinoma — Poorly differentiated sigmoid colon adenocarcinoma with CAM5.2 expression.

CAM5.2 - Lung Small Cell Carcinoma — Small cell carcinoma of the lung stained with CAM5.2.

CAM5.2 - Small Intestine — Normal small bowel epithelium stained with CAM5.2.

CAM5.2 - Salivary Gland — Salivary gland epithelium stained with CAM5.2.

CAM5.2 - Placenta — CAM5.2 expression in placental tissue.

CAM5.2 - Lung Adenocarcinoma — Lung adenocarcinoma stained with CAM5.2.

References

Tamas, EF, Epstein, JI. (2007). Detection of residual tumor cells in bladder biopsy specimens: pitfalls in the interpretation of cytokeratin stains. American Journal of Surgical Pathology, Mar;31(3):390-7.

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

Hsu, J.-D., Yao, C.-C., Han, L.-W., & Han, C.-P. (2010). CAM5.2 is not identical to cytokeratins 8 and 18. American Journal of Clinical Pathology, 133(3), 514. doi:10.1309/AJCPAKB6JEBVMX5U