CCL28 and breast cancer: Variable selection with Lasso resulted in a 9-protein (CCL8, CCL23, CCL28, CSCL10, S100A12, IL-10, IL-10RB, STAMPB2 and TNFβ; Additional file 2; Supplementary Table 3) signature, which was associated with worse breast cancer-specific survival (SHR 9.56; 95% CI 3.17–28.8, P < 0.0001) as assessed with Fine-Gray competing risk model (Table 3).