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Newly Cloned Gene Studied for Possible Role in Breast Cancer

Newly Cloned Gene Studied for Possible Role in Breast Cancer

A team of researchers at Ohio State University's Comprehensive Cancer Center have isolated and cloned a gene that may play a role in breast cancer.

The gene is the human fibroblast growth factor-8 (FGF-8) gene. The researchers also tracked the gene's location to a region of chromosome 10. That area of the chromosome is also associated with prostate cancer and glioblastoma.

The scientists believe that the gene may have a role in breast cancer because other research has linked the FGF-8 gene to mammary cancer in mice. Mammary cancer in mice is equivalent to breast cancer in humans.

The FGF-8 gene is also of interest because it is activated by androgens. Androgens, which stimulate the development of hair growth and other male characteristics, also occur in women but only in minute amounts.

Gene Activated By Androgens

"FGF-8 is the only growth factor gene that is activated by androgens," said Ing-Ming Chiu, professor of internal medicine and the researcher who led the study.

"It's a good candidate for study as an oncogene because of its role in mouse mammary tumors. We thought the same gene in humans might be involved in hormone-dependent cancers like breast cancer and prostate cancer."

The research, published in the July issue of Oncogene, also showed that the androgen dihydrotestosterone (DHT) activates the human FGF-8 gene in laboratory cells.

"We have found that DHT activates the FGF-8 gene in laboratory-grown breast cancer cells," said Chiu, "but that alone is not evidence of a connection between the FGF-8 gene and breast cancer."

The researchers are now studying human breast tumor tissue provided by breast surgeon Michael Walker at the Arthur G. James Cancer Hospital and Research Institute for the expression of the FGF-8 gene.

"We also want to learn if this gene plays a role in male breast cancer and in prostate cancer," said Chiu. Breast cancer is rare in men, with an estimated 1,400 new cases and about 260 deaths occurring annually. Breast cancer in women has an estimated 184,300 new cases and 44,300 deaths.

Chiu's laboratory was the first to clone the gene from fibroblast growth factor-1 (FGF-1), which is important for cells that form connective tissue. The protein produced by the FGF-1 gene is present in glioblastoma.

"Our research on the FGF-8 gene is a natural extension of our work on FGF-1," he said. Normally, the FGF-8 gene is important during embryonic development. In adults, it is also active in the ovaries and testes, although its role in these tissues is unknown.

If Chiu and his colleagues do find a link between cancer and the FGF-8 gene, it might mean that the gene could serve as a marker for breast cancer. It might also provide a new target for drugs designed to inhibit tumor development.

 
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