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A new study blames cheeseburgers, french fries, and other western high-fat diets for making prostate cancer more aggressive and causing it to spread. Prostate cancer is normally considered a slow-growing and low-risk disease.
Pier Paolo Pandolfi, the director at the Beth Israel Deaconness Medical Center in Boston, said their data provide a strong genetic foundation for the mechanisms underlying metastatic progression. The study also showed how environmental factors can boost these mechanisms to promote progression from primary to advanced metastatic cancer.
Prostate Cancer Progression
The progression of prostate cancer to the metastatic stage represents a pivotal event that influences patient outcomes and the therapeutic options available to patients, Pandolfi said. About 20 percent of metastatic prostate cancers lack two tumor-suppressing genes, the PML and PTEN, which are known to play a major role in prostate cancer.
The researchers compared the two types of tumors and found that the metastatic tumors produced large amounts of lipids or fats. They observed that the local tumors that do not have the PTEN gene versus the metastatic tumors lack both genes. But when the tumors did not have both PTEN and PML tumor-suppressing genes, the fat-production machinery of the cells would run amok.
When researchers hiked the levels of saturated fat, the kind found in fast food menu, in the diet of animals, the rodents developed aggressive, metastatic tumors. Pandolfi said that it was as if they found the tumors to be lipogenic or a switch for fat production. If there is a switch, the researchers can block the switch and prevent metastasis or even cure metastatic prostate cancer.
But Ming Chen, the first author and an HMS research fellow in medicine in Pandolfi’s laboratory, said that while it is widely postulated that the western diet can promote the progression of prostate cancer, direct evidence that supports a strong association between dietary lipids and prostate cancer has been lacking.
However, epidemiological data links dietary fats and obesity to many types of cancer. Science Blog noted that the rates of cancer deaths from metastatic cancers, including prostate cancer, are much higher in the US than in other countries where diets have lower fat content.
Although prostate cancer affects 10 percent of males in Asian nations, it goes up to 40 percent when the men immigrate to the US. Their prostate cancer rate mirrors the rates among native-born US population, pointing to an environmental factor that could work along with genetic factors to drive the aggressive and fatal male ailment.
He disclosed that the researchers are testing fatostatin, an obesity drug discovered in 2009. It blocked the lipogenesis fantastically and the tumors regressed and did not metastasize, Business Standard reported.
Fatostatin, a molecule, is currently being investigated for the treatment of obesity. Pandolfi's team tested the molecule in lab rodents. He said the obesity drug blocked lipogenesis fantastically, while the tumors regressed and did not metastasize.
He said the findings could result in more accurate and predictive mouse models for metastatic prostate cancer and speed up the discovery of better therapies for the ailment.
Blood Test Confirms Prostate Cancer
Meanwhile, researchers at Nottingham Trent University and University Hospital Leicester NHS Trust found that the body’s immune system changes when cancer is present. All it needs to confirm the presence of prostate cancer is a simple blood test which could prevent 70 percent of painful biopsies, The Telegraph reported.
Professor Masood Khan, a consultant urologist at the University Hospital Leicester NHS Trust and a visiting professor at Nottingham Trent University, said the blood test has the potential to spare males with non-cancerous disease or low-risk cancer from unneeded invasive diagnostic procedures and tests.
The current blood test that looks for prostate-specific antigen – a biomarker that goes up when cancer is present in the prostate gland – will show varied readings between individuals, but it goes up naturally as men grow older.
It is further complicated by the fact that higher levels of the antigen do not necessarily mean that the patient has prostate cancer. But a normal reading does not mean the man is cancer-free. The researchers trialed the new test on 72 males. It would be used following a PSA test to help physicians decide if a high PSA reading really means the patient has prostate cancer.
It monitors white cells in the blood that are responsible for protecting the body against infection and cancer. To determine if cancer is present based on how the cells are reacting, the scientists developed an algorithm.
Current UK government guidelines state that men between the ages 50 and 69 whose PSA reading is 3 or higher are advised to have a biopsy. By preventing 70 percent of biopsies, it would save the country’s health services money.
Although almost 50,000 Briton males are diagnosed with prostate cancer yearly in the UK, thousands will develop symptoms that will turn out to be harmless.
[메디컬리포트=Vittorio Hernandez 기자]