P4HA2 and ductal breast carcinoma in situ: The proportion of cases with high P4HA2 was greater in DCIS-mixed than pure DCIS, both within the tumour epithelial cells (54% of pure DCIS cases vs. 64% of DCIS mixed with IBC, χ2 = 8.6, p = 0.003) and stromal cells (25% for pure DCIS vs. 50% of DCIS mixed with invasion, χ2 = 39.3, p < 0.0001).