Introduction: During the past decades, the incidence rate of stomach cancer in western countries has shown a great decrease, while it is still the most common cancer among men in Iran. The MYC proto-oncogene, which is located at 8q24.1, regulates 15% of genes and is activated in 20% of all human tumors. MYC amplification and overexpression of its protein product has been reported in 15-30% of gastric neoplasias. The aim of this investigation was to find the preference of CISH (Chromogenic in situ hybridization) or IHC (Immunohistochemistry) in diagnosis and prognosis of gastric cancer, as well as the relationship of amplification and expression of C-MYC gene with patients’ survival.
Methods: In this cross-sectional study, 102 samples of gastric cancer were collected from patients who had undergone primary surgical resection at Cancer Institute Hospital, Tehran University of Medical Sciences. All samples were randomly selected from those who were diagnosed with adenocarcinoma gastric cancer. CISH and IHC methods were done on all of them.
Results: Patients were classified into two groups. The first group was contained stage I and II. The second group was involved stage III and IV. Survival test for both groups was carried out with CISH test. Results showed that the group II (stage III & IV) with CISH+ have less survival than those with CISH-(P=0.233), but group I (stage I & II) patients had no significant in survival with CISH+ or CISH-(P=0.630). Kaplan-Meier for both groups was performed with IHC test and showed the similar results. This data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in men than women. Our data also showed that CISH+ patients (43%) were more frequent in compare with IHC+ patients (14.7%).There was also a correlation between CISH and IHC.
Conclusion: Our conclusion was that for a plan of treatment for gastric cancer patients, by focusing on expanding the tumor, which is the most concern of the surgeons and patients, the CISH is a better and more feasible test than IHC, in regard to sensitivity and specificity. CISH can also be used as a feasible test for prognostic and tumor growth in the stage III and IV. This study indicated that C-MYC amplification in gastric cancer is correlated with survival time in advanced stages and its rate reduced in stages III and IV.