RESUMO
BACKGROUND: We assessed the role of E-cadherin (CDH1), runt-related transcription factor 3, p21waf and p27 promoter methylation (PM) and protein expression in Helicobacter pylori (HP)-associated gastric carcinomas (GCs) and adjacent non-neoplastic tissues (ANNTs). PATIENTS AND METHODS: 192 cases were assessed for PM and protein expression of CDH1, RUNX3, p21waf and p27 by methylation-specific PCR (MSP) and immunohistochemistry. The CagA gene was also assessed. RESULTS: In GCs, 66 (34.4%) and 84 (43.8%) cases showed CDH1-PM and reduced expression. It is significantly affected in GCs rather than in non-neoplastic groups (p < 0.001). In ANNTs, 108 (56.3%) cases showed CDH1-PM and all cases revealed preserved protein expression. RUNX3-PM was detected in 78 GCs (40.6%) and 69 ANNTs (35.9%), whereas reduced protein expression was detected in 99 (51.65%) GC compared to ANNTs 90 (46.9%). p21WAF and p27 showed PM in (48.4% and 45.3%) GCs and ANNTs; respectively. p21waf protein was reduced in 90 (46.9%) cases and 91 ANNTs (47.4%). p27 was reduced in 86 (44.8%) cases and 87 ANNTs (45.3%). CDH1 aberrations correlated with HP in tumors and ANNTs and with diffuse/intestinal tumors (p = 0.014, p = 0.014 and p = 0.02). RUNX3 aberrations associated with HP (p = 0.04), high grade (p = 0.04), and advanced stage (p = 032). Tumor grade associated with RUNX3-PM, CDH, p21 and p27 protein (p < 0.05 for all). Tumor stage associated significantly with PM and reduced protein expression of all markers. Positive lymph nodes associated significantly with p27PM (p < 0.001). CONCLUSIONS: HP plays an important role in the development and progression of GC through silencing of CDH1, RUNX3, p21WAF and p27 expression.
