Interleukin-1 family expression in human breast cancer: interleukin-1 receptor antagonist.

We hypothesize that interleukin-1 alpha, beta, and receptor antagonist (IL-1 alpha, IL-1 beta, and IL-1 ra, respectively) are present and tumor cell associated in human breast cancer (HBC). We believe the levels of these cytokines in breast tumor homogenates relate to other known prognosticators of patient survival (i.e., estrogen receptor [ER] status). Our results demonstrated that, immunohistochemically, tumor cells express IL-1 alpha, IL-1 beta, and IL-1 ra in most specimens tested. In breast tissue homogenates, IL-1 alpha levels correlated inversely with ER levels (p < 0.06), whereas IL-1 ra levels correlated directly with both ER levels (p < 0.009) and IL-1 beta levels (p < 0.06). When analyzing cytokine levels for the ER (-) versus ER (+) patient groups, we found that in many instances these groups showed a different cytokine profile. These studies suggest that the IL-1 family of cytokines may be important in regulating protumorigenic activities within the HBC tumor microenvironment.