Unique cancer cells stay after anti-cancer treatment

Scientists found that after treatment, a subset of resistant cancer cells exist in breast cancer tumors. These cells look different, defining a "gene signature" that can be used to develop new drugs against the disease.

After a breast cancer patient undergoes anti-cancer or anti-hormone treatment, some resistant cancer cells remain. Researchers led by Baylor College of Medicine found that of these remaining cells, some look like connective tissue (mesenchyme). Dr. Jenny Chang, medical director of the Sue and Lester Smith Breast Center noted, "We have found that gene expression patterns in a subset of these resistant cancer cells differ from those associated with the bulk of the epithelial cells in the tumor.” After chemotherapy, the tumor contained a higher percentage of tumor-initiating (breast cancer stem cells) cells, and after or hormone treatment, genes associated with the mesenchymal cell phenotype were increased in breast tumors.

This study supports a growing body of evidence that there is a particular subpopulation of cells in breast cancer that may be responsible for disease recurrence, resistance to treatment, and perhaps metastasis (cancer spread)," said Dr. Chang.

The researchers aim to develop drugs utilizing the resistant cancer cell gene signature, and to then pair the drug with conventional therapy “to eradicate all populations of cells within tumors.” The report is in the current issue of the Proceedings of the National Academy of Sciences.