Serum pseudocholinesterase levels in murine C3H mammary adenocarcinoma.

Serum pseudocholinesterase (PSC) levels may be depressed in persons with malignancy. Deficiency of this enzyme can lead to prolonged apnea in patients who receive succinylcholine. An animal model was developed to study this phenomenon in a controlled setting. C3H/HeJ mice inoculated subcutaneously with C3H mammary adenocarcinoma demonstrated lowering of their PSC levels. This decrease was attenuated by chemotherapy with intraperitoneal cyclophosphamide which also prolonged survival. Non-tumor bearing control animals identically treated with cyclophosphamide experienced a transient drop in PSC on the 29th day which reverted to control values by the 36th day. No gradient of PSC could be demonstrated across a tumor's vascular bed. The effect of other chemotherapy agents on PSC is unknown. A possible role for PSC as a non-specific marker for malignancy is worthy of further study.