Stains & CD markers
Cytokeratin CAM 5.2


Last author update: 16 June 2023
Last staff update: 16 June 2023

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PubMed Search: CAM 5.2

Kemal Kösemehmetoğlu, M.D.
Nat Pernick, M.D.
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Cite this page: Kösemehmetoğlu K. Cytokeratin CAM 5.2. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsCAM52.html. Accessed February 22nd, 2024.
Definition / general
  • Low molecular weight keratin that mainly reacts with human keratin proteins corresponding to Moll's peptides #7 (KRT7, 48 KD) and #8 (KRT8, 52 KD) on secretory epithelia of normal human tissue and associated adenocarcinomas
Essential features
  • Low molecular weight keratin (mainly reacts with K7 and K8)
  • Diffuse and strong cytoplasmic expression but some tumors show dot-like staining pattern
  • Almost all glandular epithelia and adenocarcinomas are positive, whereas squamous epithelium and squamous cell carcinomas usually do not show CAM 5.2 expression
  • Excellent accompaniment to pankeratin in the immunopanel to confirm or rule out the epithelial nature of tissue, tumors or components of tumors
  • References: Cell 1982;31:11, J Clin Pathol 1984;37:975, Am J Pathol 1990;136:657
Terminology
  • Antibody generated by using the human colorectal carcinoma cell line HT24
  • Anti-CAM 5.2 reacts with the majority of epithelial tumors, including lung, liver, pancreas, GI tract, breast, genitourinary system, female reproductive organs and some endocrine organs (Cell 1982;31:11)
  • Not a pankeratin but reacts with many epithelia and their neoplasms due to the abundance of K7 and K8 throughout the body
Pathophysiology
  • There is controversy regarding which keratins CAM 5.2 reacts with; it was originally described as highlighting both K8 and K18 by Makin et al. but now it has been shown to react with K7 and K8, not K18 and K19 (J Clin Pathol 1984;37:975, Am J Pathol 1990;136:657)
  • K7 and K8 antigens are widespread in human epithelia, especially on secretory epithelia but not on the stratified squamous epithelium
Interpretation
  • Cytoplasmic staining, usually diffuse and strong
  • Dot-like staining especially in neuroendocrine tumors, rhabdoid tumors, desmoplastic small round cell tumor, etc.
Uses by pathologists
Prognostic factors
Microscopic (histologic) description
  • Usually strong and diffuse cytoplasmic staining in adenocarcinomas or can be dot-like, especially in neuroendocrine tumors
Microscopic (histologic) images

Contributed by Kemal Kösemehmetoğlu, M.D.
Normal liver

Normal liver

Colon mucosa

Colon mucosa

Tonsil

Tonsil

Pancreas

Pancreas

Peritoneum

Peritoneum

Dendritic cell staining in lymph node

Dendritic cell staining in lymph node


Signet ring carcinoma of stomach Signet ring carcinoma of stomach

Signet ring carcinoma of stomach

Signet ring carcinoma infiltrating omentum Signet ring carcinoma infiltrating omentum

Signet ring carcinoma infiltrating omentum

Paget disease of nipple Paget disease of nipple

Paget disease of nipple


Nipple duct adenoma Nipple duct adenoma

Nipple duct adenoma

High grade neuroendocrine carcinoma High grade neuroendocrine carcinoma

High grade neuroendocrine carcinoma


CAM 5.2 in Crooke cell adenoma CAM 5.2 in Crooke cell adenoma CAM 5.2 in Crooke cell adenoma

CAM 5.2 in Crooke cell adenoma

CAM 5.2 in sparsely granulated somatotroph adenoma CAM 5.2 in sparsely granulated somatotroph adenoma CAM 5.2 in sparsely granulated somatotroph adenoma

CAM 5.2 in sparsely granulated somatotroph adenoma


CAM 5.2 in sarcomatoid carcinoma CAM 5.2 in sarcomatoid carcinoma CAM 5.2 in sarcomatoid carcinoma

CAM 5.2 in sarcomatoid carcinoma

Inflammatory myofibroblastic tumor of the bladder Inflammatory myofibroblastic tumor of the bladder

Inflammatory myofibroblastic tumor of the bladder


CAM 5.2 in epithelioid sarcoma (proximal variant) CAM 5.2 in epithelioid sarcoma (proximal variant) CAM 5.2 in epithelioid sarcoma (proximal variant)

CAM 5.2 in epithelioid sarcoma (proximal variant)

CAM 5.2 in desmoplastic small round cell tumor CAM 5.2 in desmoplastic small round cell tumor

CAM 5.2 in desmoplastic small round cell tumor

Positive staining - normal
Positive staining - disease
Negative staining
Sample pathology report
  • Omentum, biopsy:
    • Adenocarcinoma, signet ring cell type (see comment)
    • Comment: Histologic sections show a small number of signet ring-like discohesive and monotonous cells highlighted by CAM 5.2 and mucicarmine.
Board review style question #1
Which one of the following diagnoses is expected to show dot-like staining with CAM 5.2?

  1. Malignant mesothelioma
  2. Paget disease of nipple
  3. Sarcomatoid carcinoma
  4. Signet ring carcinoma
  5. Sparsely granulated hypophyseal adenoma
Board review style answer #1
E. Sparsely granulated hypophyseal adenoma. Sparsely granulated somatotroph tumors have distinct fibrous bodies that appear as pale spherical inclusions on H&E staining and stain strongly with CAM 5.2 and CK18 antibodies as well as AE1 / AE3. There is a growing evidence that sparsely granulated somatotroph adenomas are larger, more common in younger female patients and are more proliferative and infiltrative (Endotext: Pathology and Pathogenesis of Pituitary Adenomas and Other Sellar Lesions [Accessed 5 January 2023]).

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Reference: Cytokeratin CAM 5.2
Board review style question #2


A 30 year old male nonsmoker with hematuria has undergone transurethral resection. The bladder mass invades the muscularis propria (not shown); histological morphology and CAM 5.2 expression are shown above. Which antibody should be requested to reach the correct diagnosis of inflammatory myofibroblastic tumor?

  1. ALK
  2. Desmin
  3. DOG1
  4. GATA3
  5. Pankeratin
Board review style answer #2
A. ALK. Keratin expression is a common finding in inflammatory myofibroblastic tumor of bladder. In this morphological setting characterized by spindle cells with inflammatory background, ALK expression along with SMA in myofibroblastic staining pattern will lead to the correct diagnosis of inflammatory myofibroblastic tumor. Here, the diagnosis of sarcomatoid carcinoma is a major pitfall given the abundant keratin expression and infiltrative pattern (Am J Surg Pathol 2006;30:1502).

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Reference: Cytokeratin CAM 5.2
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