Alteration of lipid metabolism associated with malignant disease is well-documented and some studies have suggested a reduced stearic to
oleic acid ratio occurs in erythrocytes in
cancer patients. In this study, the
fatty acid composition was measured in platelets, which are capable of
lipid synthesis and have a much shorter lifespan. While demonstrating any
malignancy related change in the platelet stearic to
oleic acid ratio the study aimed to assess whether it could be of value as a tumour marker. Patients with active
malignancy (n = 46) had a lower ratio of stearic to
oleic acid than those with malignant disease in clinical remission [mean (S.D.) 1.08 (0.22) vs. 1.26 (0.30), P less than 0.01], and 22 healthy controls [1.29 (0.24), P less than 0.001]. However in a group of 17 patients with chronic, non-malignant diseases the ratio was also lower than in normal controls and similar to that seen in the active
malignancy group [0.97 (0.29)]. Thus while a reduction in platelet stearic to
oleic acid ratio was found in active
malignancy, it is not specific to neoplastic disease.