Cytokeratin 7

CK7 immunostain in acinar adenocarcinoma of the lung.

Cytokeratin 7, also keratin 7 and CK7, is a common low molecular keratin and a very common immunostain.

Positive

Classic positive

• Ovary.
• Breast.
• Endometrium.
• Salivary gland.
• Lung (adenocarcinoma, small cell).
• Thyroid gland.
• Mesothelium.

• Pancreas.
• Stomach.
• Urothelial carcinoma.
• Esophageal adenocarcinoma.

Negative

Classic negative

• Kidney (clear cell renal cell carcinoma). ‡
• Colon and rectum.
• Prostate.
• Thymus.
• Squamous cell carcinoma.

Notes:

• ‡ Most other common types are CK7 +ve (papillary RCC, chromophobe RCC, clear cell papillary RCC)

See also

• Cytokeratin 20.
• Cytokeratin 19.