ABSTRACT
Gastric cancer is the second most common cancer worldwide. The purpose of this study was to compare the recently identified interleukin [IL]-18, as well as IL-6 values in patients with gastric ulcer and gastric cancer to assess their diagnostic and prognostic values in patients with gastric cancer. The study comprised 40 patients attended for diagnostic upper gastrointestinal [GIT] endoscopy; 14 with histopathologically proven gastric cancer [Group I], 16 patients with gastric ulcer [Group II] and 10 patients with normal upper GIT endoscopy who served as controls [Group III]. All involved individuals were subjected to clinical examination, liver and renal function tests, complete blood picture, ESR, C-reactive protein, plain chest X-ray, abdominal ultrasound, urease test and gram staining of mucosal biopsies for Helicobacter pylori detection. Additionally chest,abdominal CT and bone scanning for group I gastric cancer were done to detect any metastasis. IL-18 and IL-6 gastric muscosal mRNA expression was assessed by quantitative real time-PCR [QRT-PCR] and their serum levels were estimated by ELISA. Gastric mucosal mRNA expression in parallel to serum values of IL-18 and IL-6 showed significant highly in-creased values in gastric cancer group compared to gastric ulcer and control groups [P<0.001] with elevated values in gastric ulcer group than those in controls. In gastric ulcer group, a positive relation was found between the studied cytokines and the histologically graded precancerous gastric lesions; gastric glandular atrophy grade was correlated with ser-um IL-18 [r=0.77; P < 0.001], gastric mRNA expression of IL-18 [ r= 0.603;P < 0.01] and IL-6 [r = 0.457;P <0.05], also intestinal metaplasia was positively related to IL-18 serum [t=-2.977; P < 0.01] and gastric mRNA expression [t =-2.365; P < 0.05] values. Higher cytokine values were related to H pylori infection in gastric ulcer [P < 0.01] not in gastric cancer group. In gastric cancer group a significant positive correlation was found between the cellular differentiation grade and IL-18 serum [r = 0.712; P <0.01] and gastric mRNA expression [ r = 0.658;P < 0.01] values, while IL-6 serum [r = 0.817; P <0.01] and gastric mRNA expression [r=0.844; P <0.01] values were positively correlated with the gastric cancer stage. Also patients with distant metastasis showed significantly higher IL-6 serum[t=-6.218 ; p < 0.001] and gastric mRNA expression [t = -2.47; P < 0.01]values compared to those without metastasis
In conclusion: IL-18 as a recently identified cytokine as well as IL-6 suggested to be vitally involved in gastric cancer pathogenesis. Serum IL-18 and IL-6 may be useful diagnostic markers for patients with gastriccancer. IL-18 may be used as a predictive marker of tumor grade and serum IL-6 could be used as a tumor marker for advanced gastric cancerstage and metastasis