The role of interleukin 8 and matrix metalloproteinases 2 and 9 in breast cancer treated with tamoxifen

PURPOSE To evaluate the role of interleukin 8 (IL8) and matrix metalloproteinase (MMP) 2 and 9 as potential parameters of response to adjuvant tamoxifen and to examine possible associations between biomarkers that might imply possible biological dependence. METHODS The study included 59 postmenopausal breast cancer patients who received adjuvant tamoxifen. Biomarker levels were determined by ELISA in cytosol tumor extracts. RESULTS Estrogen receptor (ER) proved as a reliable parameter of response to tamoxifen; patients with ER+ status had significantly longer median relapse-free survival (RFS) compared to those with ER- status (p=0.04). Patients with IL8-status had longer median RFS compared to those with IL8+ status (77 and 53 months, respectively) but without significant difference. Patients with MMP9+ status had longer median RFS compared to those with MMP9-status (92 and 66 months, respectively) but without significant difference. There was no significant difference in RFS between the subgroups formed according to MMP2 median value. A significant positive correlation was found between IL8 and MMP9 levels (p<0.001). Expression of MMP9 was significantly higher in patients with IL8 levels higher than the median (p=0.001). CONCLUSIONS IL8 showed a tendency to act as an unfavorable parameter while MMP9 showed a tendency to act as a favorable parameter of response to tamoxifen, whereas the role of MMP2 as a potential predictive parameter is more complex. The results indicate that possible existence of positive feedback between IL8 and MMP9 might contribute to progression of breast cancer.