Combined Use of Helicobacter pylori Genotyping and CDX2 Expression as a Predictor of Malignant Potential in Gastric Intestinal Metaplasia.

Objective: Gastrointestinal metaplasia (GIM) has a close relationship with gastric cancer (GC), but it is unclear how to judge which GIM could develop into GC. This study aimed to assess the role of CDX2 and its association with Helicobacter pylori (H.pylori) genotypes in GIM.

Methods: CagA and vacA genes were identified via PCR in 466 H. pylori-positive gastric tissues, including gastritis (n=104), GIM diagnosed endoscopically (GIM-1; n=82), gastric cancer (GC; n=173), and paired adjacent GIM tumors resected surgically (GIM-2; n=107). GIM was subclassified per the HID- AB pH2.5-PAS as follows: type I (n=23), type II (n=43), and type III (n=16) in GIM-1; type I (n=8), type II (n=40), and type III (n=59) in GIM-2. CDX2 expression was evaluated immunohistochemically.

Results: In GIM-1, the infection rate of vacAm2 (55.8%) and vacAs1m2 (53.5%) was higher in subtype II than in others (P<0.05), while that of vacAm1 (49.2%) and vacAs1m1 (33.9%) was higher in subtype III than in others. The cagA⁺ rate was higher in subtypes I (75.0%) and III (64.4%) than in subtype II (40.0%; P<0.05) respectively. CDX2 was upregulated in subtype I than in subtypes II and III in GIM-1 and GIM-2. In GIM-2 and GC, CDX2 was downregulated in vacAm1, vacAs1m1, and cagA⁺ (P<0.05). The predominant genotype was vacAs1m2 in subtype II of GIM-1, CDX2 expression remaining unaltered; however, the predominant genotype was cagA⁺ vacAs1m1 in subtypes II and III of GIM-2, negatively correlated with CDX2 expression.

Conclusion: These GIM subtypes (cagA⁺ vacAs1m1 H. pylori-positive GIM with negative CDX2 expression) resemble GC and should be evaluated similar to cancerous GIM.