Chronic inflammation is associated with increased risk of cancer development, whereas the link between chronic inflammation and esophageal carcinogenesis is still obscure heretofore. This study aimed to investigate the relationship between chronic inflammation and DNA damage, as well as the possible role of DNA damage in esophageal carcinogenic process. Endoscopic esophageal biopsies from 109 individuals from Chaoshan littoral, a high-risk region for esophageal squamous cell carcinoma (ESCC), were examined to evaluate the association between chronic inflammation and histological severity, while additional 204 esophageal non-tumor samples from patients with ESCC were collected. Immunohistochemistry was performed to detect the oxidative DNA damage and DNA double-strand breaks (DSBs). Significantly positive correlation was observed between degree of chronic inflammation and esophageal precursor lesions (rs = 0.37, P < 0.01). Immunohistochemical analysis showed that oxidative DNA damage level was positively correlated with the degree of chronic inflammation (rs = 0.21, P < 0.05). Moreover, the level of oxidative DNA damage positively correlated with histological severity (rs = 0.49, P < 0.01). We found that the extent of DSBs was progressively increased with inflammation degree (P < 0.01) and the progression of precancerous lesions (P < 0.001). Collectively, these findings provide evidence linking chronic inflammation-associated genomic instability with esophageal carcinogenesis and suggest possibilities for early detection and intervention of esophageal carcinogenesis.
Keywords: DNA double-strand breaks; chronic inflammation; esophageal carcinogenesis; genomic instability; oxidative DNA damage.