Endoscopic and Pathological Characteristics of Helicobacter pylori Infection-Negative Early Gastric Cancer

Background: The characteristics of Helicobacter pylori (HP) infection-negative gastric cancer (HPINGC) have not been well documented because of the rareness. The aim of this study was to classify HPINGC endoscopically and clinicopathologically.

Methods: This retrospective study included 1,741 early gastric cancer lesions and evaluated their HP infection status. Expression levels of MUC5AC, MUC6, MUC2, CD10, p53, MIB-1, pepsinogen-I, H+/K+ ATPase, chromogranin A, E-cadherin, and gastrin were evaluated in tumors by immunohistochemistry (IHC).

Results: Among the analyzed lesions, 19 (1.1%) were diagnosed as HPINGC and classified into 6 types: undifferentiated (5 lesions), fundic gland (2 lesions), cardiac gland (1 lesion), pyloric gland (3 lesions), foveolar (5 lesions), and mixed (3 lesions) types. Undifferentiated lesions were of pale color, with unclear demarcation and decreased E-cadherin expression. Fundic-type lesions were tan to reddish in color, with submucosal tumor-like protrusions, and positive for pepsinogen-I and H+/K+ ATPase. The cardiac gland type was located in the gastroesophageal junction and was positive for MUC6 and pepsinogen-I. Pyloric gland-type lesions were of the same color as normal mucosa, with mild elevation and unclear demarcation, likely positive for CD10 and chromogranin A. Foveolar epithelial-type lesions were white and elevated, with defined demarcation, and contained MUC5AC-positive cells. Mixed-type lesions, showing various staining patterns in IHC, had both elevated and depressed shape and reddish color.

Conclusion: Endoscopic observation and IHC were useful for classifying the characteristics of HPINGC, which may preserve the characteristics of its region of origin.