P4HA2 and ductal breast carcinoma in situ: These findings are further supported by gene expression profiles that showed P4HA2 mRNA level is higher in IBC than DCIS.22,23 Stromal fibroblasts as well as tumour cells can produce P4HA2 and affect the surrounding ECM.21 Our data showing strong tumour epithelial cell expression is entirely consistent with this report.