A University of Michigan (Ann Arbor, MI) research team presented preliminary study results regarding a protein marker for breast cancer at the annual meeting of the American Association of Cancer Research (AACR; Philadelphia) held in San Francisco this April. The results indicate that the protein RhoC may be a marker for small, invasive breast cancers that are likely to metastasize. Using this marker, doctors may be able to determine whether a patient needs more-aggressive treatment.

Recent developments in the field are leading the way toward faster, more-accurate methods to diagnose breast cancer. According to the Centers for Disease Control and Prevention (CDC; Atlanta), breast cancer is the most common cancer among American women and is second only to lung cancer as the leading cause of cancer-related death in the United States. The American Cancer Society (Atlanta) estimates that in the United States 192,200 new cases of breast cancer were diagnosed among women and 1500 among men in 2001.

Currently, determination of tumor size is an integral part of the staging system that determines treatment and predicts outcome. But size is often not the best indicator of the stage of the disease. Some small tumors begin spreading the disease, and in such cases, a less-aggressive treatment could reduce the odds for survival.

"With more-reliable markers for metastatic potential, clinicians would have a more-informative measure than size alone to aid in prescribing appropriate therapy," said Celina G. Kleer, MD, coprincipal investigator and assistant professor of pathology at the University of Michigan Health System, at the AACR meeting.

Also presented at the conference was new research using the serum HER-2/neu oncoprotein test. The test may help oncologists assess Herceptin-based therapy in patients with metastatic breast cancer.

It has been shown that decreasing serum values of HER-2/neu in serum are reflective of response to therapy, while increasing serum levels may indicate further progression of the disease. The HER-2/neu test quantitatively determines the serum levels.

"The data suggest that monitoring with this oncoprotein blood test can help physicians treat their metastatic breast cancer patients," says Wolfgang Johannes Köstler, MD, an oncologist in the department of internal medicine at University Hospital (Vienna, Austria). "In addition to health implications, optimizing treatment may also have a positive impact on cost."

Meanwhile, results of a study published in the April 2002 issue of Nature Genetics provide evidence that a specific mutation in the CHEK2 gene may account for 1% of all breast cancers in women and 9% of breast cancers in men. Mutations in the BRCA1 and BRCA2 genes have been known risk factors for quite some time, but only account for a small percentage of all breast cancer cases. This finding has led researchers to seek out other genes that may play a role in breast cancer.

The researchers involved in the CHEK2 study screened individuals from 718 families with a history of breast cancer, but without the BRCA1 or BRCA2 mutations. According to the study results, men with a CHEK2 mutation are 10 times more likely to contract breast cancer than those without it, and women are twice as likely.

More importantly, the study indicates that the BRCA1, BRCA2, and CHEK2 mutations are part of a biological pathway that's been implicated as a genetic source of not only breast cancer, but other cancers as well.

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