Medically Reviewed By:
Written By:
Last Modified April 14, 2022
This page features 4 Cited Research Articles
Fact Checked
Our fact-checking process begins with a thorough review of all sources to ensure they are high quality. Then we cross-check the facts with original medical or scientific reports published by those sources, or we validate the facts with reputable news organizations, medical and scientific experts and other health experts. Each page includes all sources for full transparency.
Reviewed is the nation’s most trusted mesothelioma resource

The Mesothelioma Center at has provided patients and their loved ones the most updated and reliable information on mesothelioma and asbestos exposure since 2006.

Our team of Patient Advocates includes a medical doctor, a registered nurse, health services administrators, veterans, VA-accredited Claims Agents, an oncology patient navigator and hospice care expert. Their combined expertise means we help any mesothelioma patient or loved one through every step of their cancer journey.

More than 30 contributors, including mesothelioma doctors, survivors, health care professionals and other experts, have peer-reviewed our website and written unique research-driven articles to ensure you get the highest-quality medical and health information.

About The Mesothelioma Center at

  • Assisting mesothelioma patients and their loved ones since 2006.
  • Helps more than 50% of mesothelioma patients diagnosed annually in the U.S.
  • A+ rating from the Better Business Bureau.
  • 5-star reviewed mesothelioma and support organization.
Learn More About Us


"My family has only the highest compliment for the assistance and support that we received from The Mesothelioma Center. This is a staff of compassionate and knowledgeable individuals who respect what your family is experiencing and who go the extra mile to make an unfortunate diagnosis less stressful. Information and assistance were provided by The Mesothelioma Center at no cost to our family."
Mesothelioma patient’s daughter
  • Google Review Rating
  • BBB Review Rating
Read Our Testimonials

Pathologists use immunohistochemistry to tell apart different forms of cancer and different cancer cell types. Calretinin is one of several immunohistochemical markers used to diagnose malignant mesothelioma.

A 2017 study in BMC Cancer showed calretinin is useful for detecting all major subtypes of malignant mesothelioma except the sarcomatoid cell type. That study also discussed calretinin as a possible target for a new treatment approach.

A 2013 study in the International Journal of Cancer had already shown calretinin is essential for mesothelioma cell growth and survival.

What Is Calretinin?

Calretinin is a binding protein involved in calcium signaling. It is encoded by the CALB2 gene and plays an essential role in how cells work.

Calretinin is naturally expressed in certain neurons in the nervous system. It is also found in specialized cells such as Leydig cells, which produce testosterone in men.

The protein is expressed in several other locations, including hair follicles. Calretinin has become a useful biomarker for illnesses such as Hirschsprung disease and malignant mesothelioma.

Using Calretinin to Diagnose Mesothelioma

Calretinin is a protein. Antibodies are made against the protein to detect malignant mesothelioma. Doctors use the protein to tell the difference between epithelioid and biphasic mesothelioma — the two most common cell types of the cancer. The protein also helps distinguish mesothelioma from adenocarcinoma.

Pathologists do this by staining a cancer tissue sample with a calretinin antibody that reacts to calretinin. A calretinin stain tests positive in most cases of mesothelioma.

Like many other biomarkers, calretinin is not useful for detecting sarcomatoid cells. Sarcomatoid mesothelioma is the rarest cell type and the most difficult to treat. Only about 31 percent of sarcomatoid cases test positive for calrentinin.

Pathologists may test for podoplanin, another immunohistochemical marker, when sarcomatoid mesothelioma is suspected.

In the 2017 BMC Cancer study, calretinin had a high success rate of detecting mesothelioma, except in sarcomatoid cases.

The study included 199 cases of pleural mesothelioma in Australia and Germany. It compared calretinin to mesothelin, an established biomarker found in all mesothelioma cells. Calretinin’s performance was comparable with mesothelin. Combining both markers increased diagnostic sensitivity from 66 to 75 percent.

Researchers hope combining calretinin and mesothelin with other biomarkers will one day make the early detection of malignant mesothelioma possible. Currently, most cases of mesothelioma are diagnosed after tumors spread and symptoms arise.

“That would be a major step toward the application of biomarkers in medical surveillance programs of workers with former exposure to asbestos,” the authors of the study concluded.

Differentiating Mesothelioma from Other Cancers

Calretinin was the first biomarker to differentiate epithelioid and biphasic mesothelioma from adenocarcinoma. Adenocarcinoma is the most common type of cancer that forms in the lungs, prostate, esophagus and colon.

There is a statistically significant difference in the staining pattern of calretinin between mesothelial cells and adenocarcinoma cells. Because of this, calretinin plays an important role in preventing mesothelioma misdiagnosis.

Calretinin as a Potential Target for Mesothelioma Treatment

In the 2013 study, researchers explored calretinin’s functions in tumor development. They found the depletion of calretinin in mice models led to mesothelioma cell death within 72 hours and blocked cell growth. These promising results make calretinin a potential target for mesothelioma gene therapy.

“These results demonstrate that downregulation of CR [calretinin] had a strong effect on the viability of MM [malignant mesothelioma] cells,” the authors of the study wrote.

A drug targeting CALB2 — the gene that encodes calretinin — could potentially treat mesothelioma. Another approach would be a drug that downregulates calretinin itself.

Get the Compensation You Deserve
Healthy fish, vegetables and fruit
Watch Our Free Mesothelioma Nutrition Webinar
Lab technician using a microscope in a lab
Immunotherapy & Mesothelioma Clinical Trials

Tell us what you think
Did this article help you?
How did this article help you?
What about this article isn’t helpful for you?
Did this article help you?

Thank you for your feedback. Would you like to speak with a Patient Advocate?