Expression of pepsinogen C in human breast tumours and correlation with clinicopathologic parameters.

We have examined by immunohistochemistry the ability of breast carcinomas to produce pepsinogen C, an aspartyl proteinase usually involved in the digestion of proteins in the stomach. A total of 113 out of 245 breast tumours (46%) were positive for pepsinogen C immunostaining. There was a significant association between pepsinogen C and oestrogen receptors with proteinase levels higher (HSCORE) in oestrogen receptor positive tumours than in oestrogen receptor negative. There was also a significant association between pepsinogen C and histological grade, pepsinogen C levels being higher in well and moderately differentiated breast carcinomas than in poorly differentiated tumours. On the basis of these results, we suggest that pepsinogen C may be useful as a marker of good prognosis in breast cancer.