Molecular analysis of early lesions may be key to choosing best treatment.

2003 JUN 5 - (NewsRx.com & NewsRx.net) -- A team of researchers from Massachusetts General Hospital (MGH) and the biotechnology company Arcturus has discovered molecular changes occurring in early stages of breast cancer that characterize the aggressive potential of the tumor. Thus, early molecular analysis of biopsy samples may provide key information for choosing the best therapeutic options.

The researchers have identified a gene expression signature - groups of genes that are "turned on" in a tumor cell - that may represent the molecular basis for the current classification employed in the clinical management of breast cancer. The report will appear in the Proceeding of the National Academy of Sciences USA and has been posted on the journal's online early edition at www.pnas.org/papbyrecent.shtml.

"Our results are significant because they could change the way we think about the course of cancer progression. The molecular results provide new insight into the pathological changes that we have been observing for decades," said Dennis Sgroi, MD, of the department of pathology at MGH, cosenior author of the current report.

"Correlating new methods for diagnosing cancer based on gene expression signatures with currently accepted and proven pathological classifications is an important step in developing more effective strategies for diagnosing and treating breast cancer," he added. "A major goal of our research is to demonstrate that new molecular analysis technologies can generate accurate gene expression signatures that precisely characterize tumor cells and that these signatures can be used to determine the molecular origin of the criteria pathologists use to classify tumors." Sgroi is director of breast pathology at MGH and is an assistant professor of pathology at Harvard Medical School.

The authors noted that it is widely held that breast cancer begins at a premalignant stage called atypical ductal hyperplasia, progresses into the preinvasive stage of ductal carcinoma in situ and culminates in the potentially lethal stage of invasive ductal carcinoma. Contrary to the researchers' initial expectations, the different stages of breast cancer showed remarkably similar molecular signatures or patterns of gene expression. Specifically, the preinvasive stages of breast cancer within one patient demonstrated a gene expression pattern that was highly similar to the pattern seen in the invasive, potentially lethal stage. This suggests that the genes conferring ...