Cytokeratin 7 (CK7)


What is cytokeratin 7?

Cytokeratin 7 (CK7) is a protein that is made by normal cells in the lung, breast, female reproductive organs (ovaries and endometrium), thyroid gland, and salivary glands (for example the parotid gland). It is also produced by some cells in the stomach and pancreas. Tumors that start from one of these cell types may also produce CK7.

CK7 belongs to a larger family of proteins called cytokeratins, which are responsible for helping cells maintain their structure. Other cytokeratins include cytokeratin-5 (CK5), cytokeratin-6 (CK6), cytokeratin-20 (CK20), cytokeratin-8 (CK8), and cytokeratin-19 (CK19).

What tests do pathologists perform to look for CK7?

Pathologists use a test called immunohistochemistry to ‘see’ CK7 protein inside cells. The CK7 protein is normally found in a part of the cell called the cytoplasm or cell body.

What does positive for CK7 mean?

Positive for CK7 means that immunohistochemistry was performed and CK7 protein was seen inside the cells of interest in the tissue sample. Reactive is another term that pathologists use to describe cells that are producing CK7.

What does negative for CK7 mean?

Negative for CK7 means that immunohistochemistry was performed and CK7 protein was not seen inside the cells of interest in the tissue sample. Non-reactive is another term that pathologists use to describe cells that are not producing CK7.

Why do pathologists look for CK7?

Pathologists commonly perform immunohistochemistry for CK7 on tumour samples in order to determine the tumour type or to look for specific types of cells within the tumour.

Tumours that produce CK7

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