Mesothelioma Diagnosis

Once you have been examined by your doctor one of three different types of diagnostics tests may be advised: non-invasive; minimally invasive; or invasive tests. Your doctor will determine which tests are appropriate to help with a diagnosis.

Non-Invasive Diagnostic Tests

Tests that can be performed which do not involve the removal of blood, body fluid or tissue are called non-invasive. They involve imaging studies which include the following: conventional chest x-rays, high resolution chest CT scans, MRI’s and PET scans. Most of these techniques are not ideal for a definitive diagnosis but can be useful under appropriate circumstances as directed by your physician.

Minimally Invasive Diagnostic Tests

Minimally invasive means the use of tests that remove samples of the body’s fluid or tissue in very small quantities. These diagnostic tests include: serum markers obtained through blood tests, pleural fluid analysis, biologic diagnostic markers, and fine needle biopsy.

Biologic diagnostic markers include measuring Hyaluronic acid, SMRP and Osteopontin. These are not ideal for a definitive diagnosis but can be useful under appropriate circumstances as directed by your physician.

Invasive Diagnostic Tests

These are tests that involve procedures that are more invasive and take larger tissue samples. These include: transparietal biopsy, thoracoscopy and thoractomy. Samples obtained through these three procedures can then be examined under an electron microscope and/or analyzed by use of immunohistochemical stains.

The cells are examined under this high powered microscope to determine if specific patterns are present which would help diagnose mesothelioma.

Immunohistochemical examination is performed on the tissues samples obtained in the sections above. The examination involves positive markers (those that react positively would be considered mesothelioma as opposed to other cancers) and negative markers (those where a negative reaction would tend to indicate mesothelioma as opposed to other cancers). Again, you must be guided by your doctor on the importance of each of these tests.

Some of the more prevalent positive marker immunohistochemical examinations include the following: Calretinin, CK 5/6, D2-40, Podoplanin, WT1, SMRP, Osteopontin, CD141, EMA, N-Cadherin, and Vimentin.

Some of the more common negative markers used in immunohistochemical examinations include the following: Ber-EPA, TTF1, CEA, B72.3, Monoclonal antibody B72.3, EMA, CD15, Monoclonal antibody BG-8, Monoclonal antibody CA 19-9, MOC-31, E-Cadherin, and BG-8.

In general Calretinin, CK 5/6, WT1, and Podoplanin are considered to be the best positive mesothelioma tissue markers and CEA, MOC-31, B72.3, and Ber-EP4 the best negative markers for distinguishing between epithelioid mesotheliomas and adenocarcinomas. In cases when these are not sufficient, electron microscopy can be performed. Again, this information should all be evaluated by your treating physician and he should make the final decision.