4 New Breast Cancer Genes Identified

Scientists have identified four new breast cancer genes and
predict that more clues on the genetics of breast cancer await discovery.

The findings may ultimately help scientists understand who's at risk for
breast cancer and what to do about it.

Doctors already know that variations in the BRCA1 and BRCA2 genes make
breast cancer and ovarian cancer more likely. But experts have long suspected
that other genes also affect breast cancer.B

Now, researchers say they've found four genes that affect breast cancer
risk. But the new findings don't explain all cases of breast cancer. A complex
mix of genetic and lifestyle factors likely affect breast cancer risk.

Breast Cancer Genetics

In three new studies, scientists compared the genes of women with breast
cancer with women without breast cancer.

The first study, published online in Nature, comes from researchers
including Douglas Easton, PhD, director of Cancer Research U.K.'s genetic
epidemiology unit in Cambridge, England.

Easton's team screened the genes of nearly 4,400 women with breast cancer
and 4,300 women without breast cancer. They checked their results in more than
44,400 other women, roughly half of whom had breast cancer.

Four genes -- the FGFR2, TNRC9, MAP3K1, and LSP1 genes -- had variations
that were more common in women with breast cancer than in women without breast
cancer, the study shows.

Further Findings

The other two studies, published online in Nature Genetics, echo some
of Easton's findings.

In one study, researchers screened the genes of 1,776 women with breast
cancer and 2,072 women without breast cancer. Four variations in the FGFR2 gene
were more common in the women with breast cancer than in the women without
breast cancer.

The FGFR2 gene suppresses tumors. Mutations in that gene may mar tumor
suppression.

"This finding opens up new avenues of research into the causes and
prevention of breast cancer," states researcher David Hunter, MBBS, ScD, in
a Harvard news release.

Hunter works in Boston in the medicine department of Harvard Medical School
and Brigham and Women's Hospital.

In the other study, researchers in Iceland compared genes of more than 4,550
women with breast cancer and more than 17,570 women without breast cancer.
Certain DNA variations -- including a spot near the TNRC9 gene -- were more
common in the breast cancer patients.

The findings varied "markedly" among different ethnic groups, write
the scientists, who included Simon Stacey, PhD, of Decode Genetics in
Reykjavik, Iceland.

Genetic Screening?

Genetic tests for the BRCA1 and BRCA2 genes are already in use for certain
high-risk patients.

But it may be too soon to start screening for the four new breast cancer
genes, since the findings need to be confirmed in other studies.

"It is premature to recommend screening women for these gene
variants," states Hunter, referring to his team's findings about the FGFR2
gene variations.

By Miranda Hitti
Reviewed by Louise Chang
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