Prognostic value of auto-antibodies in the serum of Omani patients with gastric cancer.

OBJECTIVE To investigate the prevalence of a group of different autoantibodies, in Omani patients with gastric cancer, and to examine whether their presence correlates with clinical course of the disease. METHODS Ninety-three Omani patients with gastric cancer, and 100 gender-matched blood donors were investigated for the presence of 15 different auto-antibodies against nuclear antigens (ANA), extractible nuclear antigens (ENA), Scleroderma antigen (Scl-70), Sjogren syndrome antigen A/B (SSA/B), Smith antigen (Sm), ribonucleoprotein (RNP), Jo-1 antigen, double stranded DNA (ds-DNA), parietal cell antibodies (APCA), reticulin antibodies (ARA), smooth muscle antibodies (ASMA), proteinase 3 (PR3), myeloperoxidase (MPO), and mitochondria antibody (AMA). Antinuclear antigen were detected using human epithelial cells-2 (Hep-2 cells). Anti-dsDNA antibodies were measured using Crithidia lucilia slides; APCA, ARA, and ASMA were examined using mouse liver, kidney, and stomach sections. Other autoantibodies were detected using commercially available ELISA kits. Seventy-three out of the 93 patients with gastric cancer were divided into 4 groups (stages I to IV) according to disease severity. This study was conducted in the period of 2001-2005 in the Department of Microbiology and Immunology Laboratories of the College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman. RESULTS Approximately 40% of the autoantibodies investigated were found to be significantly higher in patients with gastric cancer than in normal controls. These autoantibodies are ANA (57.3 versus 14%, p<0.0001), anti-ENA (38.7 versus 13.9%, p<0.01), anti-Scl-70 (29 versus 5%, p<0.001), ARA (19.8 versus 3.1%, p<0.0001), ASMA (72.9 versus 31.6%, p<0.01), and anti-PR3 (21.5 versus 5.3% p<0.01). Generally, the presence of auto-antibodies was more frequent in stage III and IV compared to stage I and II. However, some autoantibodies (ENA, SSA, Scl-70, and ASMA) were more common in stage II than stage IV. CONCLUSION Auto-antibodies are more prevalent in the serum of patients with gastric cancer compared to healthy controls. Some of these auto-antibodies may prove to be important markers of prognostic values in patients with gastric cancer.