Sensitive Determination Of DNA Oxidative Damage Biomarker In Urine By Mass Spectrometry And Its Application In Early Warning Of Colorectal And Breast Cancer

BackgroundDiscovery of novel tumor markers is of great importance for early warning of cance.DNA oxidative damage can lead to cytotoxic effects and involves the development and progression of a variety of malignant tumors.8-hydroxy-2’-deoxyguanosine has been commonly chosen as a biomarker of oxidative DNA damage.However,there is currently a lack of a convenient and sensitive detection method.In this study,a sensitive ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry(UPLC-ESI-MS/MS)method for the determination of oxidative damage marker in urine was established.The urine samples from healthy volunteers,patients with colorectal cancer,breast cancer or benign breast disease were detected.The association between oxidative DNA damage and the risk of cancer was studied and the potential of oxidative DNA damage biomarker as biomarker for early warning of cancers were discussed.MethodsIn this paper,ultra-high performance liquid chromatography-tandem mass spectrometry was used to carry out research.A highly sensitive mass spectrometric detection method for 8-hydroxy-2’-deoxyguanosine was established by optimizing mass spectrometry parameters and screening for the best mobile phase additives.Then,using the established highly sensitive detection method,the urine samples of colon cancer,early breast cancer,benign breast disease patients and normal people were quantitatively determined.Logistic regression model was used to analyze the relationship between the risk of colorectal cancer and breast cancer and the concentration of 8-hydroxydeoxyguanosine in urine.Results1.The results showed that acetic acid could improve the response of 8-hydroxy-2’-deoxyguanosine in MS by 2.7-5.3 times.The mechanism of acetic acid to improve the response was further studied.It was found that acetic acid improves the ionization efficiency of 8-hydroxy-2’-deoxyguanosine by suppressing the formation of the metal adducts during the ESI process.2.The levels of urinary 8-hydroxy-2’-deoxyguanosine were markedly increased in patients with colorectal cancer relative to the healthy controls.Moreover,for patients with colorectal cancer,the content of urinary 8-hydroxy-2’-deoxyguanosine concentration elevated gradually from stage Ⅰ to Ⅳ,and for patients with tumor metastasis,the content of urinary 8-hydroxy-2’-deoxyguanosine was significantly higher than that in patients without tumor metastasis.Logistic regression analysis was performed,and the results revealed that urinary 8-hydroxy-2’-deoxyguanosine could be utilized in prediction of colorectal cancer risk and highly effective detection of colorectal cancer.3.The concentration of urinary 8-OHdG in patients with early-stage breast cancer was significantly higher not only than that in healthy controls,but also than that in patients with benign breast diseases,whereas no significant difference of urinary 8-OHdG level was observed between benign breast diseases group and healthy control group.Logistic regression analysis indicates that the marked increase of 8-OHdG in urine may serve as a potential biomarker for the risk estimation,early screening and detection of breast cancer,particularly for discriminating early-stage breast cancer from benign lesions.Conclusion1.This paper established a highly sensitive mass spectrometric detection method for urinary DNA oxidative damage marker 8-hydroxydeoxyguanosine.2.The levels of 8-hydroxy-2’-deoxyguanosine in urine can be used for colorectal cancer risk prediction and early warning.3.The level of 8-hydroxy-2’-deoxyguanosine in urine can be used for early warning and screening of breast cancer,especially for distinguishing early breast cancer from benign breast disease.