Detection and clinical significance of plasma glutathione-S-transferases in dogs with lymphoma

Background. The objective of this study was to determine if glutathione-S-transferases were detectable in the plasma of dogs and to determine if concentrations of the alpha- and pi-subtypes were related with tumor response to single agent anthracycline (e.g, doxorubicin) chemotherapy in dogs with lymphoma. Materials and Methods. Plasma was obtained fi om 10 healthy normal dogs and from II dogs with lymphoma before treatment, 3 weeks after I dose of doxorubicin and every 3 weeks thereafter until relapse (the physical detection of recurrent and enlarged peripheral lymph nodes). Plasma concentration of a and alpha-GST was determined by use of an ELISA technique with well plates pre-coated with Igc[anti-Canine alpha-GST or anti-Human pi-GST]. Results. Mean plasma alpha-GST concentrations did not significantly decline after Idose of doxorubicin chemotherapy; however, mean plasma alpha-GST concentrations were markedly increased (p < 0.05) at the time of relapse (the physical detection of recurrent and enlarged peripheral lymph nodes). Conclusions. In this study we show that a relationship exists between the plasma alpha-GST concentration and the clinical response of dogs with lymphoma to doxorubicin chemotherapy.