[Clinicopathological characteristics of early gastric cardiac carcinoma from specimens of endoscopic submucosal dissection].

Objective: To investigate the clinicopathological characteristics of early gastric cardia adenocarcinoma from the tissue specimens obtained by endoscopic submucosal dissection (ESD). Methods: A retrospective study was designed on 133 patients with early cardiac gastric cancer (cardiac group) and 142 patients with early non-cardiac gastric cancer (non-cardiac group) who underwent ESD procedure at Xiangcheng County People's Hospital in Henan Province and the Pingdingshan Medical District of the 989th Hospital of the Joint Logistic Support Force from January 2012 to June 2025. The clinical, endoscopic, pathological, immunophenotypic data and prognostic factors of the two groups were systematically compared. Results: The patients in the cardiac group were older [(64.6±8.9) years vs. (62.3±9.3) years; t=2.086, P=0.038] and had tumor of a larger size, with diameters [16.0 (10.0, 26.0) mm vs. 14.0 (8.0, 22.0) mm; Z=-2.041, P=0.041] compared with those in the non-cardiac group; endoscopically, type 0-Ⅱc lesions accounted for a higher proportion in the cardiac group than in the non-cardiac group [(92/133, 69.2%) vs. (75/142, 52.8%); χ²=7.896, P=0.019]. Predominate histopathological type was well-to-moderately differentiated tubular adenocarcinoma in both groups; however, the cardiac group showed significantly higher proportions of cases with concomitant papillary adenocarcinoma [(21/133, 15.8%) vs. (11/142, 7.7%); χ²=4.321, P=0.038], mild cellular atypia [(43/133, 32.3%) vs. (30/142, 21.1%); χ²=4.421, P=0.035], surface coverage by normal epithelium [(50/133, 36.1%) vs. (21/142, 14.8%); χ²=16.580, P<0.001], surface coverage by mild atypical epithelium [(39/133, 29.3%) vs. (19/142, 13.4%); χ²=10.489, P=0.001], and coexistence with gastritis cystica profunda [(25/133, 18.8%) vs (11/142, 7.7%); χ²=7.371, P=0.007] compared with the non-cardiac group. Immunohistochemically, the cardiac group showed a higher rate of aberrant p53 protein expression than the non-cardiac group [(42/69, 60.9%) vs. (30/100, 30.0%); χ²=15.911, P<0.001]. Within the cardiac group, the MUC5AC positive rate was significantly higher in cases with aberrant p53 expression than in those with normal p53 expression [(40/42, 95.2%) vs. (19/27, 70.4%); χ²=8.201, P=0.004]. Multivariate regression analysis confirmed that aberrant p53 protein expression was independently associated with MUC5AC positivity (OR=12.22, P=0.032). Short-term follow-up [cardiac group: 36.0 (25.0, 45.5) months, non-cardiac group: 37.0 (25.8, 49.3) months] showed no statistically significant difference between the two groups (Z=1.455, P=0.146), and no recurrence or metastasis was observed in either group. Conclusions: Early cardiac gastric cancer shows the coexistence of occult histology and highly aberrant p53 protein expression, closely coupled with the gastric phenotypic marker MUC5AC, suggesting that early cardiac gastric cancer may represent a distinctive tumor subtype.