The value of immunohistochemical expression of TTF-1, CK7 and CK20 in the diagnosis of primary and secondary lung carcinomas
Wednesday, July 16th, 2008.
Saudi Medical Journal. 2008 Jul;29(7):957-61. [Link]
Al-Zahrani IH.
Department of Pathology, Faculty of Medicine, King Abdul-Aziz University Hospital, PO Box 80215, Jeddah 21589, Kingdom of Saudi Arabia. Tel. +966 505693399 Fax. + 966 (02) 6408433. E-mail: ibrahimzahrani@hotmail.com.
Abstract
Objective: To study the value of immunohistochemical staining of thyroid transcription factor-1 TTF-1, cytokeratin 7 CK7, and cytokeratin 20 CK20 in the differentiation between primary and secondary pulmonary carcinomas.
Methods: Forty-three cases of lung carcinoma, 14 squamous cell carcinoma, 12 adenocarcinoma, 8 small cell carcinoma, 3 mesothelioma, and 6 metastatic tumors, were collected from the files of the Pathology Department, King Abdul-Aziz University Hospital, Jeddah, Saudi Arabia between 2004 and 2006. All cases were stained immunohistochemically following Avidin biotin method using monoclonal antibodies to TTF-1, CK7, and CK20.
Results: Immunohistochemical staining of 43 cases of lung carcinoma revealed nuclear immunoreactivity for TTF-1 in all primary adenocarcinoma, and small cell carcinoma, while cases of squamous cell carcinoma were negative. Mesotheliomas were negative to TTF-1, CK7, and CK20. Metastatic tumors except for one case metastatic from the thyroid gland were negative to TTF-1. Cytokeratin 7 was positively expressed in primary tumors of lung, as well as metastatic tumors from the thyroid and breast. Cytokeratin 20 was negative in all primary lung tumors, while positive in metastatic carcinomas from the colon.
Conclusion: Thyroid transcription factor-1 is a sensitive marker for diagnosis of primary pulmonary adenocarcinoma, and differentiation between poorly differentiated squamous cell carcinoma and small cell carcinoma and adenocarcinoma. Cytokeratin 20 could be a marker for metastatic tumors from the colon to the lung since it was negative in all primary lung tumors.
Glossary
- adenocarcinoma
- (add-en-o car-sin-o-muh). Cancer that starts in the glandular tissue, such as in the ducts or lobules of the breast.
- squamous cell carcinoma
- (skwa-mus cell car-sin-oma) cancer that begins in the non-glandular cells, for example, the skin.
- monoclonal antibodies
- antibodies made in the laboratory and designed to target specific substances called antigens. Monoclonal antibodies which have been attached to chemotherapy drugs or radioactive substances are being studied to see if they can seek out antigens unique to cancer cells and deliver these treatments directly to the cancer, thus killing the cancer cells without harming healthy tissue. Monoclonal antibodies are also used in other ways, for example, to help find and classify cancer cells.
- differentiation
- (dif-er-en-she-A-shun) the normal process through which cells mature so they can carry out the jobs they were meant to do. Cancer cells are poorly differentiated.
- diagnosis
- identifying a disease by its signs or symptoms, and by using imaging procedures and laboratory findings. The earlier a diagnosis of cancer is made, the better the chance for long-term survival.
- colon
- the large intestine, part of the digestive tract. The colon is a muscular tube about 5 feet long.
- cell
- the basic unit of which all living things are made. Cells replace themselves by splitting and forming new cells (mitosis). The processes that control the formation of new cells and the death of old cells are disrupted in cancer.
- carcinoma
- (car-sin-o-ma) a malignant tumor that begins in the lining layer (epithelial cells) of organs. At least 80% of all cancers are carcinomas.
- mesothelioma
- a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.
