To the Editor.—
Mitochondrial creatine kinase (CK-MIT) is an isoenzyme of creatine kinase thought to be of mitochondrial origin that migrates cathodically to the MM fraction on electrophoresis. Bark, in his report entitled "Mitochondrial Creatine Kinase" (1980;243:2058), observed CK-MIT in eight patients, most of whom suffered acute myocardial infarction. All experienced shock with poor tissue perfusion, and six of the eight died within a brief period. He concluded that the presence of CK-MIT indicated severe tissue damage, particularly myocardial, and poor prognosis.We recently detected apparent CK-MIT in two patients without heart disease or shock, both of whom had metastatic carcinoma.
Report of Cases.—Case 1.—
A 63-year-old man complained of low-back pain, night sweats, weakness, and a 12-kg (27-lb) weight loss over several weeks. An examination led to an exploratory laparotomy, at which time multiple nodules were found in the liver. Biopsy findings indicated malignant lymphoma. Although his