Cis linoleic acid, a potential biomarker for squamous cell carcinoma of the skin.

Abstract

A population based case-control study was designed to test the hypothesis that cases of squamous cell carcinoma (SCC) had lower concentration of cis linoleic (LA) in their red blood cell membranes and it would remain a predictor of SCC after adjusting for other risk factors. The probability of LA as a potential biomarker for SCC was investigated because it is the precursor of arachidonic acid (AA), a secondary messenger for proteins involved in cell growth and proliferation. Ras oncogene perpetually activates the two phospholipases A-2 and C, causing release of AA from the membrane phospholipids. Red blood cell membranes were used as the medium for assessing the concentration of cis linoleic acid because donation of blood was well accepted by the participants. Tissue availability, and the low cost of operation were the other factors to utilize red blood cell membranes. Cases who had confirmed pathological diagnosis of SCC between December 1991-October 1994 were identified and consecutively sampled from the Arizona Skin Cancer Registry. Controls were recruited from the same geographic area using a random digit dialing technique. Subjects, limited to White-Anglo European descendent, were frequency matched by their age (± 5 years). Participants were screened for use of steroids, prescribed non-steroid anti-inflammatory drugs and history of chronic illness. Data on sun exposure habits, medication usage, lifestyle habits, and family history of SCC were collected during a personal interview. A 15 cc blood sample was collected. The composition of fatty acids in the red blood cell membranes was analyzed using gas-liquid chromatography techniques. Statistical analysis revealed that concentration of LA was significantly lower in the red blood cell membranes of the cases than the controls. However, cases had higher concentration of linolenic and trans linoleic acids. The concentration of 17 other fatty acids were equal, indicating that the general dietary pattern of cases and controls were similar. Use of logistic regression statistics showed that LA remained a significant independent risk factor for SCC (OR = 2.83, 95% Cl = 1.38-5.97) after adjusting for other risk factors. Based on this preliminary research, it is cautiously suggested that LA could be used as a potential biomarker of SCC.