POSTN and Fibroadenoma: Decorin was present at higher levels in fibroadenomas than in phyllodes tumors (P = 0.009, Mann-Whitney U test; n = 37, 35) (Figure 2c), whereas periostin was present at lower levels in fibroadenomas (P = 0.007, Mann-Whitney U test; n = 37, 35) (Figure 2d).