The expression of 8-hydroxydeoxyguanosine in oesophageal tissues and tumours

Purpose The most common marker of oxidative DNA damage is 8-hydroxydeoxyguanosine (8-OHdG), which is linked with several malignancies. In the present study we investigated whether DNA damage linked to oxidative stress (as 8-OHdG) is present in Barrettʹs mucosa with or without associated adenocarcinoma or high-grade dysplasia and in normal controlsʹ squamous mucosa. Experimental design We measured 8-OHdG in 51 patients (13 Barrettʹs metaplasia, six Barrettʹs oesophagus with high-grade dysplasia, 18 adenocarcinoma of the distal oesophagus/oesophagogastric junction and 14 normal controls). The amount of DNA damage was determined by high-performance liquid chromatography in oesophagus samples obtained either from endoscopy or as samples from surgery. The median 8-OHdG concentration was expressed as the ratio of 8-OHdG per 105 deoxyguanosine. Results Analysis revealed that 8-OHdG was present in both Barrettʹs metaplasia with and without dysplasia as well as in adenocarcinoma of the oesophagus/oesophagogastric junction. Although the study group was small the amount of 8-OHdG was significantly increased in the distal oesophagus both in Barrettʹs epithelium 1.26 (0.08–29.47) and in high-grade dysplasia 1.35 (1.04–1.65) as well as in adenocarcinoma of oesophagus/oesophagogastric junction 1.08 (0.59–1.94) compared to controls 0.06 (0–4.08) (p = 0.002, p = 0.012, p = 0.001, respectively). Barrettʹs patients had no significant difference in 8-OHdG levels between their distal and proximal oesophageal samples. Conclusions Our results show the presence of oxidative DNA damage in the distal oesophagus of patients with Barrettʹs oesophagus and adenocarcinoma of the oesophagus/oesophagogastric junction. This may have a connection to carcinogenesis in Barrettʹs oesophagus.