Differences in oxidative stress dependence between gastric adenocarcinoma subtypes

Area of Science:

• Gastroenterology and Oncology
• Molecular Pathology
• Biomarkers of Oxidative Stress

Background:

• Oxidative stress and nitric oxide (NO) production are implicated in carcinogenesis.
• Understanding these pathways in different gastric cancer subtypes is crucial for targeted therapies.

Purpose of the Study:

• To assess the prevalence of oxidative stress markers in pre-neoplastic and neoplastic gastric mucosa.
• To correlate these markers with clinicopathological features and histological subtypes of gastric cancer.

Main Methods:

• Immunohistochemical analysis of 104 gastric adenocarcinomas for inducible nitric oxide synthase (iNOS), nitrotyrosine (NTYR), and 8-hydroxy-2 -deoxyguanosine (8-OH-dG).
• Evaluation of marker expression in relation to tumor type (infiltrative vs. intraepithelial) and histological subtypes (tubular, diffuse, polymorphous).

Main Results:

• iNOS, NTYR, and 8-OH-dG were detected in both infiltrative and intraepithelial gastric carcinomas.
• Tubular carcinoma (TC) exhibited significantly higher iNOS and NTYR expression compared to diffuse (DC) and polymorphous carcinoma (PolyC).
• Oxidative stress markers did not significantly correlate with histological grade, tumor depth, lymph node metastasis, or overall pathological stage in infiltrative TC.

Conclusions:

• The iNOS-oxidative pathway appears to play a significant role in Tubular Carcinoma (TC) and a moderate role in Polymorphous (PolyC) and Diffuse Carcinoma (DC).
• DNA oxidation and protein nitration are present across all three gastric carcinoma subtypes.
• Distinct NTYR levels suggest TC and PolyC represent separate subtypes of gastric cancer.