Tag Archives: Biology

Vitamin A fights prostate cancer

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New research from Yorkshire Cancer Research at the University of York, has found that the humble carrot may help in the war against prostate cancer.

Carrots, along with red peppers, green vegetables and liver, contain vitamin A, which is converted in the body to a substance known as retinoic acid, which can turn up the activity of ‘twin’ genes in prostate cancer cells.

“The story, from almost 20 years ago, is that men with low vitamin A blood levels have more serious prostate cancers than men who have high or normal vitamin A blood levels, but nobody knew why,” explains Professor Norman Maitland, Director of the YCR Cancer Research Unit in the Department of Biology at York. “This is an exciting new development that links an element from our diet to prostate cancer cells.

“Cancer arises from healthy cells going wrong. Certain controls can be turned off which allows the cancer to progress. For example, cancer cells have gained the ability to grow and invade the surrounding tissues.”

“We have found that these ‘twin’ genes are turned off in malignant prostate cancer stem cells. When we turn them back on using retinoic acid the dangerous cells stop spreading.

“All-trans retinoic acid is already used to treat another type of cancer called acute promyelomcytic leukaemia (APL) and has been hugely successful in improving survival rates. For prostate cancer, retinoic acid doesn’t have to kill cells, it has to change them. This is where the research is going now, to see whether we can use low levels of retinoids to make cells more treatable.”

But before dashing off to buy a job lot of vitamin A or retinoic acid, take care, as vitamin A in large doses can be toxic. Typical symptoms of an overdose include orange skin, peeling skin, blurred vision and nausea. In extreme cases it can cause hair loss and enlarged spleen and liver, (and, in very severe cases, even death).

prostate cancer

Prostate cancer

The important point to remember is that in men who have prostate cancer and have lower than normal vitamin A blood levels, their cancer appears to be worse. Making sure that you have a normal, healthy diet, with plenty of fresh vegetables should supply you with enough vitamin A. “One hundred grams of raw carrots provides almost 17,000 units of vitamin A, (three times the recommended daily does of 5,000 units) and the same is true for red peppers,” says Professor Maitland.


Eating enough natural sources of vitamin A might be a relatively simple and inexpensive way of potentially controlling the spread of prostate cancer.

Every year in the UK almost 41,000 men are diagnosed with prostate cancer. About 80% of them survive for five years, but more than 10,000 men die each year from this disease – that is almost a quarter of all cancers diagnosed in men.

More than 50% of prostate cancer cases are diagnosed in men over 70. In the UK about one in nine men will have prostate cancer at some point in their lifetime. A family history of prostate cancer increases your risk of developing this disease.

Breast cancer enzyme discovered

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University of Minnesota researchers have uncovered a human enzyme responsible for causing DNA mutations found in the majority of breast cancers.

The discovery of this enzyme – called APOBEC3B – may change the way breast cancer is diagnosed and treated.

The findings came from a team of researchers led by Reuben Harris, Ph.D., associate professor of biochemistry, molecular biology and biophysics and also a researcher at the Masonic Cancer Center, University of Minnesota.

“We strongly believe this discovery will change the way mutations in cancer are viewed and, hopefully, it will allow cancer researchers to develop new treatments approaches that can prevent these mutations before they become harmful,” said Harris.

Harris’ quest to learn more about mutations in cancer initially began with HIV research. This previous work by Harris’ lab and others indicated that APOBEC3B and related enzymes function normally to protect from infectious viruses like HIV-1.

During these studies, Harris’ team developed specific tests to quantify the expression of each of the seven APOBEC3 genes, including APOBEC3B.

Harris and his team were able to apply these tests to the problem of mutation in breast cancer, showing only APOBEC3B is over-expressed in patients’ breast cancer cell lines and tumors.

Breast cancer

Breast cancer

“DNA mutations are absolutely essential for cancer development. Our experiments showed the APOBEC3B enzyme causes mutations in the genome of breast cancer cells. From this, we were able to reasonably conclude that the APOBEC3B is a key influencer in breast cancer,” said Harris.


However, Harris pointed out that APOBEC3B appears to be a biological “double-edged sword.” It protects some cells from viruses such as HIV-1 yet produces mutations giving rise to cancer in others.

Harris stresses the need for additional research. If further studies confirm that high APOBEC3B levels indicate the early presence of breast cancer, a simple blood test could be a strategy for early detection.

Another goal for Harris is finding a way to block APOBEC3B from causing mutation, just as sunscreen prevents sun from causing mutations leading to melanoma. His collaborative HIV studies are already pointing toward such drug possibilities.