Blood type and cancer

Blood type and cancer

A study was conducted in 2015 where researchers followed and examined about 50,000 people from the ages of 40 to 70, for a duration of seven years. They controlled certain variables in the group of people studied such as gender, smoking and education. After seven years, they found that those who had blood type A, B or AB, had a higher risk of developing stomach cancer, they also found this group to be more likely to die from heart disease when compared with those with type O blood.

Type O’s have been found to have a lower risk of developing various cancers which include colorectal, pancreatic and stomach.

More research has been done to show that those with type A have a 32% higher risk of developing pancreatic cancer, type AB have a 51% higher chance and type B have a 72% higher chance. However, screening tests for pancreatic cancer are not to be based on blood type alone as there are a number of other contributing factors.

Stomach and pancreatic cancer

If you are blood type AB, then your chance of developing stomach cancer is significantly higher than blood type O and B. This is due to a specific type of bacteria known as Helicobacter pylori. Those who have the blood type A or AB may suffer from an immune system response that is heightened, which increases the risk of developing stomach cancer. Basically, the antigens A and B enable the bacteria to thrive.

The four groups of blood types, being A, B, AB and O, are defined by the confections (compounds) of protein and sugar. These confections make up the type of glycoproteins that define the blood type. Glycoproteins are found on the surfaces of the red blood cells, amongst other cells, including those found in the pancreas.

The gene referred to as ABO is responsible for constructing the glycoproteins through placing the molecules of sugar on a protein known as the H antigen. This H antigen is like a backbone for the sugars. The specific pattern formed by the sugars is the determining factor for what the individual’s blood type is. In blood type O, the antigen does not have any sugars attached (the reason why it is known as the universal blood type).

Experiments have shown that should alterations take place in the antigens, this interference (due to the immune system’s reaction to the bacteria H. pylori) may affect the ability of the cells to adhere and signal to each other and in doing so, impact the ability of the immune system to be able to detect cells that are abnormal. This is thought to set the stage for cancer to develop.

Thus, the research suggests normal cells of the pancreas have a different pattern of the blood-type antigens when compared to pancreatic tumour cells. Therefore, a conclusion was made that changes in the ABO genes may result in cancerous cells.

It should be noted that although these findings may provide a new avenue for underpinning the cause of cancer, they do not prove that there is a direct link between pancreatic cancer and blood-type antigens. It is thought that the ABO gene should rather be viewed as a marker.

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