CHOLESTERYL 14-METHYLHEXADECANOATE AS A POSSIBLE MARKER OF MALIGNANT-TUMORS

Concentration of cholesteryl 14-methylhexadecanoate was determined by high-performance liquid chromatography in serum of 123 healthy individ uals, 83 of patients with other diseases than cancer, and of 394 patie nts with cancer. A mean level of 22.89 nmol/ml in healthy persons was not significantly different from 23.22 nmol/ml found in other diseases than cancer. With a cut-off value of 40.0 nmol/ml, there were 2 false ly positive results in the former and 4 in the later group. Significan tly elevated mean concentrations (60-80 nmol/ml) were demonstrated in most patients with cancer irrespective of the clinical stage. No diffe rences were found in this respect between males and females, and in di fferent age groups. The sensitivity of the test was 81.8% for the whol e population tested, if progressive and stable diseases as well as par tial remissions were evaluated. Lower sensitivities were found in fema les and in patients more than 60 years old (down to 70.6%). The test s howed a significantly greater sensitivity in less advanced stages of t he disease (T1 and T2). Considering the type of cancer, highest sensit ivity was observed for testicular cancer (86.2%), lower for prostatic (77.8%), mammary (76.5%), ovarian (75.8%), and colorectal tumors (73.3 %) as well as for lymphomas (70%). Follow-up of patients with all thes e types of cancer revealed that changes in their clinical condition ar e accompanied with significant alterations in the cholesteryl 14-methy lhexadecanoate level. When this ester was determined in 807 sera with a known level of other markers (irrespective of diagnosis), a signific ant correlation was demonstrated with carcinoembryonic antigen and nea rly a significant one with prostatic specific antigen. There was no co rrelation with CA 15-3, CA 19-9, CA 125, or TPA. Because of its sound theoretical basis, absolutely specific method of determination, high s pecificity (97.1%), and predictive value (94.7%), the cholesteryl 14-m ethylhexadecanoate level determination may be useful as an alternate p rocedure supplementing the spectrum of tumor markers generally used.