Assay did not recognize normal-like breast cancer cells in research appearing in JNCI.
Veridex’ CellSearch, an antibody-based prognostic test, may not detect one out of five types of breast cancer, say researchers from the Erasmus Medical Center in Rotterdam, The Netherlands.
Breast cancer has five subtypes based on their gene-expression patterns: basal, HER2-positive, luminal A and B, and normal-like. CellSearch is designed to detect circulating breast cancer cells in patients before and during treatment. Previous studies suggested that women who have a decrease in circulating tumor cells after the start of treatment are likely to have a better outcome than those who do not have a decline.
The Erasmus Medical Center team used global gene-expression profiling to determine the subtypes of a well-defined panel of 34 human breast cancer cell lines (15 luminal, nine normal-like, five basal-like, and five Her2-positive). They mixed 50–150 cells from 10 of these cell lines with 7.5 mL of blood from a single healthy human donor. The mixtures were subjected to the CellSearch test.
They found that this isolation method, which uses EpCAM on the surface of circulating tumor cells for cell isolation, did not recognize normal-like breast cancer cells, which in general have aggressive features.
The study is detailed in the December 30 online edition of the Journal of the National Cancer Institute.