Male gene teaches us about breast cancer

September 25, 2012 - 06:02

Men with breast cancer have a special gene variant, new study shows. The discovery provides new answers to why both women and men get breast cancer.

Breast cancer is known as a female disease, but on rare occasions men are also hit by the disease. If a man discovers a lump in his chest, fluid coming out of the nipple, a retraction of the nipple, wounds on the chest or swollen lymph nodes in the armpit, he should seek medical help. (Photo: Colourbox)

Breast cancer is far more common in women than in men. Nevertheless, it’s the men who are now bringing scientists one step closer to an answer to why this dreaded disease hits some but not others.

”We have made a highly surprising discovery. It offers some great new perspectives to breast cancer research in general – and also for women. Now we really have something to build on,” says Stig E. Bojesen, a doctor at the Department of Clinical Biochemistry at Herlev Hospital, Denmark.

Together with colleagues from several countries, Bojesen has studied male breast cancer patients. The findings have just been published in the scientific journal Nature Genetics.

Specific gene can cause breast cancer

The team has discovered a genetic variant in some of the men who have breast cancer. A variant has previously been found in the same gene in women with a family history of breast cancer. But since this variant is very rare in women, the scientists haven’t been all that interested in exploring it any further.

“Now it turns out that men are more likely to get breast cancer if they have this gene variant,” says Bojesen.

“And if the variant is strong enough to cause breast cancer in men, it’s only natural that we try to find out how the gene affects women. We already have some information about how the gene functions, but now we need to zoom in on it to see exactly what it does.”

We have made a highly surprising discovery. It offers some great new perspectives to breast cancer research in general – and also for women. Now we really have something to build on.
Stig E. Bojesen

Breast cancer in men only makes up one percent of all breast cancers, which is why researchers from various countries had to join forces to gather enough subjects for scientific studies.

Herlev Hospital contributed with 31 patients out of a total of 823 men with breast cancer who participated in the international project. The scientists compared these men’s gene composition with that of a group of healthy men.

Back to the lab

”We examined whether some gene variants occurred more frequently in men with breast cancer than in healthy men, and we found 17 places in the cancer patients’ genome that looked interesting. After a series of thorough examinations, we were left with only one,” explains the doctor.

“This is the first time we’ve really found anything in men, and it came as a huge surprise that we found it in this half-forgotten gene which we already know from women.”

Bojesen describes this as an important discovery which can be used to learn more about the biology of breast cancer.

We are, however, still some way away from seeing a drug that can limit the harmful effect of the gene:

This is the first time we’ve really found anything in men, and it came as a huge surprise that we found it in this half-forgotten gene which we already know from women.
Stig E. Bojesen

“Now we need to go back to the laboratory to take a closer look at how this gene variant behaves inside the cells.”

The variant in question is known as RAD51B.

The discovery provides a hint that breast cancer in men may be more of a hereditary disease than previously thought. It would therefore be a good idea for women to pay extra attention to their breasts if they are related to a male breast cancer patient, explains Bojesen.

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Read the Danish version of this article at videnskab.dk

Country
Translated by
Dann Vinther

All living organisms have gene variants in their genome, which is why no two humans, animals, plants or other species are identical.

Gene variants determine factors such as our appearance, for instance the colour of our eyes.

The variants can be passed from one generation to another. Some gene variants predispose us to various hereditary diseases.

Genetic variation is, however, also important for our ability to survive.

This is because some gene variants are resistant to certain diseases, toxins or other negative effects.

Humans and other species that have a gene variant that’s resistant to e.g. a toxic chemical will survive if the chemical spreads in the area where the species lives. The surviving individuals will eventually pass their resistant gene variants on to the next generation, thus ensuring the survival of the species.

This is why we say that genetic variation is important for evolution.