Oxidative DNA damage plays crucial roles in the pathogenesis of numerous diseases including cancer. 8-hydroxy-2′-deoxyguanosine (8-OHdG) is the most representative product of oxidative modifications of DNA, and urinary 8-OHdG is potentially the best non-invasive biomarker of oxidative damage to DNA. Herein, we developed a sensitive, specific and accurate method for quantification of 8-OHdG in human urine. The urine samples were pretreated using off-line solid-phase extraction (SPE), followed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. By the use of acetic acid as an additive to the mobile phase, we improved the UPLC-MS/MS detection of 8-OHdG by 2.7−5.3 times. Using the developed strategy, we measured the contents of 8-OHdG in urine samples from 142 healthy volunteers and 84 patients with colorectal cancer (CRC). We observed increased levels of urinary 8-OHdG in patients with CRC and patients with tumor metastasis, compared to healthy controls and patients without tumor metastasis, respectively. Additionally, logistic regression analysis and receiver operator characteristic (ROC) curve analysis were performed. Our findings implicate that oxidative stress plays important roles in the development of CRC and the marked increase of urinary 8-OHdG may serve as a potential liquid biomarker for the risk estimation, early warning and detection of CRC.

Reactive oxygen species (ROS) are generated after exposure to harmful environmental factors and during normal cellular metabolic processes. The balance of the generating and scavenging of ROS plays a significant role in living cells. The accumulation of ROS will lead to oxidative damage to biomolecules including nucleic acid. Although many types of oxidative nucleic acid damage products have been identified, 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoG) has been commonly chosen as the biomarkers of oxidative damage to DNA and RNA, respectively. It has been demonstrated that oxidative damage to nucleic acid is an initiator in pathogenesis of numerous diseases. Thus, oxidative nucleic acid damage biomarkers have the potential to be utilized for detection of diseases. Herein, we reviewed the relationship of oxidative nucleic acid damage and development of various diseases including cancers (colorectal cancer, gastrointestinal cancer, breast cancer, lung cancer, epithelial ovarian carcinoma, esophageal squamous cell carcinoma), neurodegenerative disorders and chronic diseases (diabetes and its complications, cardiovascular diseases). The potential of oxidative nucleic acid damage biomarkers for detection of diseases and drug development were described. Moreover, the approaches for detection of these biomarkers were also summarized.

Gastric cancer is the third leading cause of cancer-related mortalities worldwide and mostly incurable. It remains an urgent need for novel strategies in the management of patients with advanced gastric cancer. Chimeric antigen receptor (CAR) T therapy has shown unprecedented clinical success in hematological malignancies and potential utility is going on various solid tumors like gastric cancer. In this study, a broad expression of NKG2D ligands was observed in gastric cancer cell lines, making them suitable targets for gastric cancer therapy. T cells were engineered with an NKG2D-based second-generation CAR and the resulting NKG2D-CAR-T cells showed significantly increased cytolytic activity against gastric cancer compared to untransduced T cells. In vivo, these cells can significantly suppressed the growth of established gastric cancer xenografts. Besides, cisplatin was shown to upregulate NKG2D ligand expression in gastric cancer cells and enhance the susceptibility to NKG2D-CAR-T-cell-mediated cytotoxicity. In conclusion, NKG2D-based CAR-T cells have potent in vivo and in vitro anti-tumor activities against gastric cancer and could be a new paradigm for patients with gastric cancer, either used alone or combined with chemotherapy.

Hepatoid adenocarcinoma of the stomach (HAS) is a rare form of gastric cancer that has unique clinicopathological features and an extremely poor prognosis. Here, we report on three patients with suspected gastric cancer who were referred to our hospital. Gastrointestinal fiberscopy on the three patients revealed two lesions in the antrum and a third lesion in the gastroesophageal junction. The alpha fetoprotein (AFP) serum levels were markedly elevated in all cases. At the time of diagnosis, two cases were advanced stages with lymph nodes and/or liver metastases. Two patients underwent exploratory laparotomy. A total gastrectomy was performed on the operable lesion, and an expanded gastrectomy was completed in the case with hepatic metastases. Histopathological analysis revealed that the tumors displayed two pathological changes: hepatoid-like foci and adenocarcinomatous. Furthermore, the tumor cells were immunohistochemically positive for AFP, alpha-1 antitrypsin, and alpha-1 antichymotrypsin. All three patients received chemotherapy. The follow-up duration ranged from 8-36 mo. Our experience and previous published studies have suggested that HAS is an aggressive type of adenocarcinoma. However, radical surgery and chemotherapy may positively impact clinical outcomes.