Alterations in serum lipolytic activity of cancer patients with response to therapy.

The effect of chemotherapy on the serum lipid mobilising activity of a group of cancer patients with or without weight loss has been determined. The pre-treatment level of serum lipolytic activity in all cancer patients, with or without weight loss, was higher than normal controls (0.22 +/- 0.01 versus 0.06 +/- 0.01 mumols glycerol released ml-1 serum respectively). The pre-treatment levels of lipid mobilising activity in the patients serum was proportional to the extent of weight loss (correlation coefficient 0.81), if the extent of weight loss was small (less than 14 kg). Patients who showed a positive response to chemotherapy also showed a decrease in their plasma levels of lipolytic activity, while a patient who showed no response to therapy also showed no change in the serum lipolytic activity. There was no correlation between the serum lipolytic activity and response to megestrol acetate, a synthetic orally active progestogen, which is currently under investigation as an anticachectic agent. Serum from cancer patients showed lipolytic activity which was retained on a DEAE cellulose column and eluted by a salt gradient, in contrast with normal controls. Response to chemotherapy was associated with a decrease of the retained material, although the profile did not return to the normal state. These results need confirmation in a larger group of patients using more specific methods to determine tumour lipolytic activity, but suggest that it may be possible to monitor response to therapy by measurement of the serum lipolytic activity.