| Breast cancer is the most common malignant tumor in women.It ranks first in the incidence of female malignant tumors and it seriously threatens women’s life and health.Research and exploration of new methods for early diagnosis of breast cancer is of great significance in improving the cure rate and reducing mortality.Tumor markers can better reflect the occurrence and development of cancer and have a good auxiliary role in the clinical diagnosis and treatment of tumors.Based on this,to study the specific changes of some substances in biological fluid during the development and progression of breast cancer,in order to find specific markers that can be used for the early diagnosis of breast cancer and to establish a non-invasive diagnostic method which is for census,early diagnosis and prognosis evaluation of breast cancer providing objective evidence with extremely important practical significance.This study used high performance liquid chromatography-mass spectrometry to establish a new method for the analysis of tyrosine and its metabolites in urine.A rat model of breast cancer was established to obtain controlled urine samples.The above-mentioned targets in the urine of rats of the control group and the breast cancer model group were detected using the established method,and the data of each group were statistically analyzed to systematically investigate the level of tyrosine and its related metabolites in the rat urine relevance to breast cancer.The main research results are as follows:1.Analysis of tyrosine and its metabolites in rat urine by ultra-high performance liquid chromatography-tandem mass spectrometryA new analytical method for the determination of Tyrosine,4-hydroxyphenyl lactic acid,4-hydroxyphenyl acetic acid,3-4-hydroxyphenyl propionic acid,4-hydroxyphenethyl amine,3-4-hydroxyphenyl alanine and 2-5-hydroxyphenyl acetic acid in rat urine by ultra-high performance liquid chromatography-tandem mass spectrometry.A Shim-pack GIST C18 separation column was used with acetic acid-ammonium acetate(20 mmol/L):acetonitrile=95:5(v/v)as the mobile phase at a flow rate of 0.2 mL/min under optimized mass spectrometry conditions.The linear relationship of these substances was good(R~2>0.9991),and the detection limit was between 0.0003 and 0.0041 mg/L.The recoveries of the three levels were 82.0%-113.0%,and the RSD was less than 4.4%.The method is simple,rapid,selective,and highly sensitive.It can be used for simultaneous determination of tyrosine and its metabolites in the rat urine.2.Construction of rat breast cancer model and study of histopathologicalFemale SD rats of 5 weeks old were selected and carcinogenic to rats induced by oral(intragastric)7,12-Dimethylbenz[a]anthracene(DMBA).Histopathological study was conducted on rats in the control group and the model group.The results showed that the carcinogenicity rate of the model group rats was 83.3%.The rat breast cancer model was successfully constructed so that controllable cancer samples which study the correlation between tyrosine and its metabolites and breast cancer were obtained.3.Determination of tyrosine and its metabolites in rat urine and its correlation with breast cancerThe urine of rats in the control group and the model group was detected by the established ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)method,and the test results were statistically analyzed.The results showed that with the occurrence and development of breast cancer,the level of tyrosine and its metabolites in the urine of the model group rats will undergo a certain change;among them,when the tyrosine content in the urine of breast cancer rats is comparable to the control one,the rats in the group were lower(p<0.01),while the contents of 4-hydroxyphenyl acetic acid and tyramine in the urine of breast cancer rats were higher than those in the control group(p<0.01),and the content of4-hydroxyphenyl lactic acid was higher than Rats in the control group(0.01<p<0.05).These substances may serve as potential tumor markers for breast cancer. |
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