Anti-livin antibodies: novel markers of malignant gastrointestinal cancers

INTRODUCTION Livin represents apoptosis inhibitors and may be important in cancer. OBJECTIVES The aim of the study was to develop an anti-livin autoantibody assay and investigate its usefulness in the clinical practice in relation to gastrointestinal cancers (GIC). PATIENTS AND METHODS We studied sera obtained from 36 patients with GIC and 59 healthy controls. A solid-phase radioimmunoassay to detect anti-livin antibodies in serum was developed. Polipropylene tubes were coated with recombinant human livin, and 100-fold dilutions of sera were incubated in these tubes. On the next day, the tubes were decanted, washed and labeled 125-I protein A was added. After 2-hour incubation, the tubes were washed and radioactivity was measured using the gamma counter. RESULTS We observed a statistically significant difference between the presence and levels of anti-livin antibodies in sera of patients with GIC and in control subjects. Anti-livin autoantibodies were detected in 9 patients with GIC. Of note, the level of anti-livin antibodies was significantly elevated in 25% of GIC patients. The presence of anti-livin antibodies was confirmed with sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blotting. CONCLUSIONS A high prevalence of anti-livin antibodies in patients with GIC indicates that they may be useful in the diagnosis of these malignancies.