Pepsinogen C expression in tumors of extragastric origin

We have examined by immunohistochemistry the ability of human carcinomas of various origin to produce pepsinogen C, an aspartyl proteinase mainly invo lved in the digestion of proteins in the stomach and recently found to be a ssociated with breast carcinomas. Of the 268 tumors analyzed 80 (29.8%) sho wed positive staining for pepsinogen C. These positive tumors included 12 g astric (38.7% of the 31 examined cases), nine pancreatic (42.8%), two renal (20%), 12 prostatic (40%), three bladder (27.3%), 14 endometrial (29.7%) a nd 18 ovarian (40%) carcinomas. We also detected 10 melanomas (50%) that we re positive for pepsinogen C. By contrast, immunohistochemical staining for the proteinase was not detected in colorectal, cervical, lung and basal ce ll skin carcinomas. These results demonstrate that pepsinogen C, a proteoly tic enzyme of highly restricted expression in human tissues, can also be ex pressed by a wide variety of human carcinomas. In addition, and similar to pepsinogen C expression in breast carcinomas, the production of this enzyme by different human tumors might be related to putative hormonal alteration s associated with the development and progression of these tumors.