IL-8 is a novel marker for breast cancer

Background

Estrogen receptor (ER) status is an important parameter in breast cancer management as ER-positive breast cancers have a better prognosis than ER-negative tumors. This difference comes essentially from the lower aggressiveness and invasiveness of ER-positive tumors.

Results

Here, we demonstrate that IL-8 is clearly overexpressed in most ER-negative breast cell lines and breast tumor samples tested. We have also performed a large clinical study on breast tumor samples to determine whether IL-8 expression could be correlated with other clinical parameters. In addition, in vitro studies show that the invasion potential of ER-negative breast cancer cells is associated at least in part with expression of IL-8, but not with IL-8 receptor levels. Moreover, IL-8 increases the invasiveness of ER-positive breast cancer cells, thus confirming the invasion-promoting role of IL-8. Overexpression of IL-8 in ER-negative breast cancer cells involves a high transcriptional activity of the IL-8 promoter. By analysing the IL-8 promoter, we have identified the elements responsible for IL-8 overexpression in ER-negative breast cancer cells.

Conclusion

Taken together, these results provide the basis for the control of IL-8 expression in breast cancer and define IL-8 as a novel marker of breast cancers.