Gastric intestinal metaplasia subtypes and the effects of c-Myc expression on severity

The association between gastric intestinal metaplasia severity grades, histological subtypes, and oncogenic potential remains unclear. This study explored gastric intestinal metaplasia (GIM) subtypes and c-Myc protein expression across mild, moderate, and severe GIM cases.

A total of 180 paraffin-embedded gastroscopy biopsy samples from patients diagnosed with atrophic gastritis were selected, with 60 cases each of mild, moderate, and severe GIM. Alcian blue-Periodic acid-Schiff (AB-PAS) and high iron diamine (HID) staining were used to classify GIM into types I-III. Immunohistochemistry was performed to assess c-Myc expression, with low, moderate, and high expression defined as the percentage of c-Myc-positive cells in the GIM area of <15%, 15-40%, and ≥ 40%, respectively. Spearman and Kruskal-Wallis tests were used to analyze the correlation between GIM severity, GIM subtype, and c-Myc expression.

GIM was predominantly diagnosed in middle-aged and elderly individuals. Regarding the subtype, 53.89% were type II, 25.56% were type III, and 20.56% were type I. Low c-Myc expression was present in 47.78% of cases, moderate expression in 36.67%, and high expression in 15.56%. Neither the severity of GIM nor its subtype or c-Myc expression level was correlated with age or sex. Type III GIM accounted for approximately 10% of mild-to-moderate cases, whereas > 50% of severe GIM cases were type III. A positive correlation was found between GIM severity and subtype (r_s = 0.376, P < 0.05). There was no significant correlation in c-Myc expression across different GIM severities. From type I to type III GIM, the proportion of low c-Myc expression increased and that of high expression decreased, whereas that of moderate expression remained almost unchanged. A negative correlation was observed between the GIM subtype and c-Myc expression (r_s = -0.148, P < 0.05).

GIM incidence increases with age; however, the histological severity of GIM (as defined by the extent of mucosal gland involvement) within a single biopsy sample does not show a corresponding increase with age. The more severe the GIM is, the greater the proportion of type III GIM cases present. c-Myc expression did not correlate with GIM severity. Conversely, as the GIM subtype becomes more advanced (from type I to type III), c-Myc expression decreases.