Background: The incidence of breast cancer has been increasing annually, and breast cancer-related diseases, such as breast cancer in the young, ovarian cancer, prostate cancer, and pancreatic cancer, have clearly and steadily increased in number and have become common among the family members of patients with breast cancer. Accordingly, an increase in the incidence of familial breast cancer (FBC) is anticipated in the future. Interleukin (IL)-2 is one of the cytokines that activate CTLs, which are important for cancer immunity. To search for the markers of increased risk for FBC, we examined the sIL-2R levels and immunologic factors in patients with breast cancer and nonfamilial breast cancer (NFBC).
Methods: Of the 106 untreated breast cancer patients who gave consent to participate in this study, 24 had FBC and 82 had NFBC. There were 11 healthy individuals included in this study. Serum and peripheral blood mononuclear cells were collected from all patients for the measurement of the levels of sIL-2R, IL-10, VEGF, IL-17, Tregs, and MDSC. Prognosis was assessed and compared, according to the sIL-2R levels (low vs. high). Tissue samples from postoperative patients with high sIL2 were stained with PD-LI and CD8.
Results: The sIL-2R level was significantly higher and had significantly better correlations with IL-10, VEGF, IL-17, Tregs, and MDSC levels in FBC than in NFBC. In cases with high sIL-2R level, the Tregs and MDSC levels were significantly higher and the OS and DFS rates were significantly worse in FBC than in NFBC. Among the FBC cases with high sIL-2R level, triple-negative breast cancer tissues stained well for PD-LI and CD8.
Conclusions: Compared with NFBC, FBC was associated with higher sIL-2R levels, Th2 significance, and less aggressive cancer immunosuppressive cells. We have identified sIL-2R as a biomarker that can predict the prognosis of FBC. The ability to prospectively identify patients who are less likely to have NFBC is a vital step in improving the overall survival of this population.