P4HA2 and ductal breast carcinoma in situ: Although there was no statistically significant difference between P4HA2 expression within the tumour epithelial cells of DCIS component and invasive component of DCIS-mixed cases (p = 0.188), its expression within the stromal fibroblasts surrounding the invasive component was higher than those surrounding the DCIS component (p < 0.0001).