St. Louis Public Radio News
7:16 pm
Wed April 14, 2010

Tumor genomes may reveal how cancer spreads

St. Louis, MO – Scientists have mapped the genome of a 44-year-old African American woman with a highly lethal form of breast cancer, known as a "basal" subtype.

The researchers compared the patient's healthy DNA to the DNA sequences in her original breast tumor and in a subsequent fatal tumor that developed in her brain.

Elaine Mardis co-directs Washington University's Genome Center. She says the genome comparisons suggest that this type of cancer spreads from a small number of original breast tumor cells -- cells with mutations that allow them to survive chemotherapy and radiation.

"They not only have that ability to survive, but they also have the ability to break away from the primary tumor mass, travel through the blood, and re-establish themselves at another place or another tissue in the body."

Mardis says identifying the mutations that drive tumors to spread could eventually lead to new therapies for cancers that don't respond to existing treatments.

Basal subtype breast cancer represents about 10 percent of all breast cancers. It disproportionately affects younger women and African Americans.

The subject of this research died within a year of her initial diagnosis.