Pancreatic cancer is one of the deadliest forms of cancer known to modern medicine. The chances of a pancreatic cancer patient to survive for five years after being diagnosed with the disease is only 7%. As a term of comparison, a breast cancer patient has around 85% chance of surviving for over 5 years from the day they are diagnosed with the disease. The reason pancreatic cancer is such a painfully efficient killer is that it causes very few symptoms and is therefore almost always diagnosed when it is too late for surgery. Most often, pancreatic cancer only manifests itself through weight loss and fatigue followed by diffuse abdominal pain, all of which can easily be ignored or mis-diagnosed.
Because the symptoms of pancreatic cancer are so difficult to spot and interpret, most of the hopes for improving the prognosis of pancreatic cancer patients lie in learning how to spot the disease early by detecting the levels of specific molecules in the blood, known as biomarkers. Biomarkers are proteins that are know to be produced in higher amounts in people with a certain disease. They are routinely used when diagnosing breast and blood cancer, as well as lung and colorectal cancer. However, when it comes to pancreatic cancer the available biomarkers are not always up to their crucial task. The key molecule that is currently used to detect pancreatic is known as CAS19-9. While CAS19-9 is produced in abundance in patients that have late-stage pancreatic cancers, it is often unsuccessful in diagnosing early-stage pancreatic cancer – therefore failing to spot the disease when it is still treatable. A recent study by the University of Texas has unveiled a new set of biomarkers that can be used in conjunction with CAS19-9 to improve the detection of early-stage pancreatic cancer.
First of all, researchers identified a set of proteins that have been shown to be produced in high levels in patients with pancreatic cancer in previous studies. These proteins are known as “candidate biomarkers”. The investigators subsequently gathered blood samples from a group of patients who had been diagnosed with pancreatic cancer, as well as blood samples from healthy individuals and patients with pancreatitis. Samples from patients with pancreatitis (an inflammation of the pancreas) will be used to differentiate the effects of the cancer on the blood from the impact of cancer-associated inflammation on protein levels. The levels of the “candidate biomarkers” were then measured in these blood samples, validating them as potential biomarkers for pancreatic cancer. In particular, two molecules known as TIMP1 and LRG1 were shown to be very highly expressed in blood from pancreatic cancer patients when compared to blood from healthy individuals and from patients with pancreatitis. Therefore, these two molecules were taken through to the last stage of testing – verifying whether they can predict whether blood is from a healthy individual or a pancreatic cancer patient. Each of the three molecules (the pre-established CAS19-9 and newly-discovered TIMP1 and LRG1) was tested both independently and in combination with the other two to test whether their levels in the blood can act as a marker of pancreatic cancer. The way scientists test these associations is by measuring the levels of these molecules in blood samples of unknown origins. These experiments as known as “blind tests” – which means that the researchers measuring the levels of biomarkers in the blood and analyzing these results are unaware of whether each sample comes from a healthy person or a cancer patient. However, the origin of the sample is recorded and revealed at the end of the analysis.
What this analysis revealed once the “blinders” are taken off is that measuring the levels of TIMP1, LRG1 and CAS19-9 is a much more effective tool to predict whether a patient has pancreatic cancer than CAS19-9 alone. This means that measuring the levels of these molecules in the blood of those with potential pancreatic cancer (or those at high risk of developing pancreatic cancer – such as those with a genetic predisposition to pancreatic cancer) has a much greater chance of spotting pancreatic cancer before it progresses to an un-treatable stage.