Development of ELISA to estimate thymosin α1, the N terminus of prothymosin α, in human tumors

Abstract

AbstractWe reported that tumor content of prothymosin α (ProT α) is a proliferation index of human breast tumors that might be used to identify patients at high risk for distant metastasis (Dominguez et al., Eur J Cancer 1993;29A:893–7). In that study ProT α concentrations were measured by a RIA; here we present an alternative nonisotopic assay that could be used in a standard clinical laboratory. Main features of the ELISA are: (a) A recombinant fusion protein glutathione S-transferase (GST)–human ProT α was used to coat the microtiter plates; (b) we used a polyclonal antiserum raised in rabbits that detects thymosin α1, the NH2-terminal fragment of ProT α; (c) it is as sensitive as the RIA; (d) it is faster than the RIA. ProT α concentrations in various human tumors (skin, esophagus, colorectal, and breast) as assessed by ELISA were comparable with, although twofold greater than, the values previously estimated by RIA.