POSTN and cancer: In the prognostic analysis, patients with cancer expressing periostin, along with age, histological grade, lymph node metastasis, and triple-negative breast cancer, were shown to attain a poorer disease-specific survival than those with no or low expressed periostin protein (P = 0.001, 0.002, 0.001, 0.004, and 0.001, respectively) (Figure 6).