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Cancer is the second largest cause of death in industrialized countries. Frequency of cancer increased significantly in the last decades, and most experts consider this as a reflection of the fact that now we live longer and rarely die from infectious diseases. Cancer is more common in older patients who reached post-reproductive age.
Inherited genetic mutations increase chances of developing cancer
Usually cancer is connected to environmental factors such as pollution, bad habits (smoking, alcohol), poor diet, obesity and lack of physical activity. However, many people have increased chances of cancer due to genetic predisposition. The highest percentage of such cases is observed among patients with breast cancer, prostate cancer and ovarian cancer.
The presence of hereditary componentwas established long ago for many familial cancers but the exact genetic reasons behind the pattern were discovered only relatively recently.
Some genes confer much higher chances of cancer while others only increase the probability of cancer development by only few percents. For instance, mutations in genes BRCA1 and BRCA2 are often associated with a very high risk of breast cancer. The carriers of these defective genes, in combination with other genetic factors, may have up to 50% chances of getting breast cancer during their lifetime, compared to one in eight chances for average women.
Obviously, those who have higher than average chances of getting cancer need to take extra care of their health and should be monitored. Reliable identification of those at higher risk, however, is not an easy task. In some cases, family history of cancer can provide certain clues, but on its own the family history analysis is not very reliable. Detection of some more common cancer-associated genes like mutated versions of BRCA1 and BRCA2 can be done easily. The problem, however, is that very often cancer predisposition is multi-factorial, and in each individual case many different genes can be involved. Detailed genetic analysis is the best way of identifying the vulnerable individual and taking care of them.
The number of cancer related genetic markers is growing fast
The studies performed by scientists from several British universities have identified more than 80 new cancer genetic markers. Researchers analyzed the DNA of 200,000 people looking for small changes associated with cancer. The findings were published earlier this year in several research papers. After publication of these results, the number of genetic alterations associated with breast cancer increased to 76. Now we are also aware of 78 genetic risk factors leading to prostate cancer and 12 genes associated with ovarian cancer. We also know a number of genes that reduce the probability of cancer.