In most cases, malignant pleural mesothelioma (MPM) is diagnosed after a person visits a doctor with symptoms they are having. These symptoms may include chest pain, shortness of breath, coughing, unusual lumps on or near the chest, weight loss, and others.
To make a diagnosis of MPM, a doctor will look at several things, including:
- Medical history
- Physical exam
- Imaging tests
- Blood tests
- Tests of body fluid and tissue
- Lung function tests
It’s very important that mesothelioma be discovered quickly in order to start treatment as early as possible. When found early, MPM may be less advanced than if it is found later. When discovered at an early stage, there are more options to treat it. For example, surgery is used much more frequently in early stages than late stages. Early diagnosis offers the possibility to give treatment to patients at an earlier time when tumors are not a big, confined to a smaller area, and more accessible to treatment.
As a result of efforts to find new ways to detect and treat MPM, more and more patients are living longer with the disease.
Biomarkers in Mesothelioma
MPM is relatively uncommon, and as a result, there are no widely-used tests to determine who may have it. One area of study that has gained attention in recent years surrounds so-called “biomarkers.” These may help with earlier diagnosis. A biomarker is anything in the body that may indicate presence of a disease or condition.
There are many examples of biomarkers in medicine:
- Body temperature is a biomarker for fever
- Cholesterol levels are biomarkers for cardiovascular problems such as a heart attack
- Blood pressure is a biomarker for a stroke
On a smaller level, many tiny molecules in the body are markers for diseases or conditions. For example, c-reactive protein (CRP) is a tiny compound that is a biomarker for inflammation. On a blood test, a high level of CRP tells doctors that there is inflammation somewhere in the body – maybe in the joints or blood vessels. Doctors can then find out where the inflammation is, administer treatment, and measure CRP once again to see if it goes back to normal. This would mean that the inflammation has improved.
In recent years, researchers have found that in people with MPM, certain biomarkers are raised or lowered. These include osteopontin, soluble mesothelin-related peptides, megakaryocyte potentiating factor, and others. Blood tests for these – and other substances as they are discovered – may one day be very useful in detecting mesothelioma earlier. They may also eventually be used to monitor the disease over time.
Fibulin-3: A New Biomarker to Help Doctors Manage Mesothelioma
Recently, there have been several studies of fibulin-3. This is a biomarker in the blood that may help to identify mesothelioma earlier.
A study published by Dr. Harvey Pass and his co-workers at New York University looked at fibulin-3 in patients with MPM. They found that levels of fibulin-3 were higher in patients with MPM than in those exposed to asbestos who did not have MPM. In their conclusions, they stated the following: “Plasma fibulin-3 levels can distinguish healthy persons with exposure to asbestos from patients with mesothelioma.” This is important since it may help doctors be able to discover MPM before symptoms appear. Then, treatment could be started earlier and patients could – hopefully – live longer.
Since the article was published, other scientists have started looking at fibulin-3 as well. For example, one study found that patients with MPM had higher pleural effusion (fluid buildup) and fibulin-3 levels than those with other types of effusion. They concluded that fibulin-3 is a good biomarker for diagnosis of MPM. It may also useful for distinguishing between MPM and other types of lung cancer.
These studies show that fibulin-3 might be a useful biomarker in patients with MPM. It could eventually help identify patients who may have MPM in order to start treatment earlier.
Moving Forward: Challenges in Biomarkers for MPM
The studies above are promising. However, there are challenges that remain. For example, a difficulty with discovering biomarkers is the choice of a comparator group. In research studies, comparisons are usually made between a sick group and a healthy group of similar age. However, the majority of patients with MPM are in their 70s or older. As a result, both the group with MPM and the healthy comparator group may have other non-MPM sicknesses or problems since they are an older population. This makes research more difficult to conduct.
Another challenge is that the first study of a biomarker often shows great promise but later studies do not show such strong results. This may be due to several things such as design of the studies, analysis of the data, sample collection, storage and processing, or others.
Additionally, blood is an extremely complex mixture. Picture it this way: in every drop of blood, there are tens of thousands of different types of proteins and other molecules. All of these are potential biomarkers. The 22 most common proteins, which are not biomarkers for cancer, account for 99 percent of blood protein content. As a result, researchers are forced to search the other 1 percent, which is a tiny bit that could be “masked” by the more abundant proteins.
In the case of mesothelioma, studying biomarkers is extremely difficult. While it is a complex process, there are many promising leads – such as fibulin-3 – that could improve the way doctors identify and treat this deadly cancer caused by asbestos.