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 auto antibody 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 γ 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 auto antibodies 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.