Low tissue enzyme activity seen in breast cancers of patients who fail adjuvant chemotherapy

Primary breast cancers from 54 patients undergoing postsurgical adjuvant chemotherapy were analyzed for several enzymes and estrogen receptors to determine if biochemical parameters might offer a prognostic index for determining outcome of therapy. Recurrence of disease during therapy or within 12 months after cessation of therapy was the criterion for classifying the patient as a treatment failure. Recurrence rates were similar in ER-positive vs. ER-negative patients, indicating that estrogen receptor status offered no predictive value in this series. However, patients who failed therapy had tumors that displayed significantly lower activities of lactate dehydrogenase, glucosephosphate isomerase, and glucose 6-phosphate dehydrogenase vs. patients who showed no evidence of recurrence for this observation period. When either premenopausal or ER-negative patients were compared, a similar observation was made; low enzyme activities occurred in patients failing to benefit from adjuvant chemotherapy. Based on this series of patients, it is suggested that a selected enzyme activity profile may offer a predictive index for recurrence in the adjuvant chemotherapy setting.