Characterization of monoclonal antibodies against stromelysin-3 and their use to evaluate stromelysin-3 levels in breast carcinoma by semi-quantitative immunohistochemistry.

Stromelysin-3 (ST3) is a matrix metalloproteinase which is expressed in fibroblastic cells of most human invasive carcinomas and represents a potential new prognostic indicator. Expression of recombinant ST3 forms in Escherichia coli from cDNA constructs indicated that high levels of expression were achieved when the ST3 pro-domain was deleted. The putative mature form of ST3 thus produced and recovered from bacterial inclusion bodies was used to prepare monoclonal antibodies (MAbs) against ST3 by immunization of BALB/C mice. Ten hybridomas producing MAbs against ST3 were obtained and analyzed for their ability to detect endogenous ST3 in breast cancer and in conditioned media from human fibroblasts. One of these MAbs (5ST-4A9) was found to be suitable for the routine detection of ST3 on breast cancer tissue sections, thus opening the possibility to evaluate ST3 prognostic value in breast cancer using semi-quantitative immunohistochemistry.