Abstract: OBJECTIVE: To investigate the value and significance of using serum protein fingerprinting to screen serum markers of breast cancer for clinical diagnosis of breast cancer. METHODS: The relative levels of serum proteins in 42 breast cancer patients were detected using the American Protein Microarray System PBSII/C type including protein fingerprinting and protein microarray, while 42 normal human sera were used as controls. RESULTS: A total of three proteins with statistically different expression peaks with mass-to-charge ratios of 4800 Da, 6410 Da and 9300 Da were found in breast cancer patients and normal human patients, and their sensitivity was 89.3% and specificity 92.7%, showing that these three serum markers were effective for breast cancer diagnosis and diagnosis. Conclusion: The serum protein fingerprinting technique has reliable data for screening serum markers of breast cancer and can be applied in the biological diagnosis of breast cancer, which should be promoted. Protein fingerprinting is a mass spectrometry-based protein analysis technique in which proteins of interest are cleaved into small peptide fragments and precisely analyzed by mass spectrometers such as matrix-assisted laser-resolved time-of-flight mass spectrometry (MALDL-TOF-MS) or electrospray time-of-flight mass spectrometry (EST-TOF-MS). Many studies have shown the effectiveness of applying protein fingerprinting techniques to clinical diagnosis, especially for screening of tumor markers. Breast cancer has become one of the important causes of death in women and its early diagnosis is significant for the control of breast cancer [1]. The aim of this study is to investigate the value and significance of using serum protein fingerprinting to screen serum markers of breast cancer for clinical diagnosis of breast cancer, and the results are reported as follows: 1. General data 1.1 Study population A total of 30 cases of breast cancer patients (who have been surgically and pathologically confirmed), aged 34-76 years old, average age 51 years old; weight 46kg The average weight of the patients was 46kg -77kg, 54.6kg; among them, there were 7 cases of stage I, 9 cases of stage II, 7 cases of stage IIIa, 3 cases of stage IIIb, and 2 cases of stage IV. Thirty cases of normal subjects were also selected as controls. There was no statistical difference in age and weight between the normal subjects and the patients. 1.2 Experimental materials and equipment The high performance liquid chromatograph was purchased from Agilent, USA, model Agilent 1200. Tris-HCL, sodium acetate, hydrochloric acid, 10×PBS Buffer, urea, trifluoroacetic acid, sodium hydroxide and other reagents were purchased from Sigma. One mass control chip all in one peptide and one all in one protein, protein chip and surface-enhanced laser-resolved ionization-time of flight-mass spectrometry ( SELDI-TOF MS) were purchased from Cipher-gen, USA. 1.3 Methods 1.3.1 Protein chip processing The chips were inserted into the biochip processor, 200 µl of binding buffer was added to each well, shaken at 500 r/min for 5 min, and the supernatant was discarded [2]. Repeat the above operation once. 1.3.21 Sample loading Add 100 ul of sample preparation to each well of the chip processor and shake at 500r/min for 1 h at 4°C. After discarding the sample, add 200ul of buffer to each well of the chip and shake at room temperature for 5 min at 500r/min in an oscillator, discard the supernatant, add 200ul of buffer again, and repeat the operation once [3]. Discard the buffer, add 200ul of deionized water to each well and immediately shake out, and wash 3 times in total. The chip processor was quickly disassembled, the chip was removed, and 0.8 SPA buffer was added dropwise to each well after the surface was dry, and dried at room temperature. 1.4 Statistical processing Protein data with differences in serum peak performance between breast cancer patients and normal subjects were analyzed with BiomakerWizard 3.1 software and SPSS13, and protein peaks with statistically significant differences were screened out [4]. Combining the weights of each peak, the discriminant analysis results of different protein peak permutations were compared, and the best combination was selected to establish a diagnostic model of protein fingerprinting for breast cancer. 2. Results A total of three proteins with statistically different expression peaks were found in breast cancer patients and normal human patients, and their mass-to-charge ratios were 4800 Da, 6410 Da and 9300 Da, respectively, with 89.3% sensitivity and 92.7% specificity, showing that these three serum markers were effective for breast cancer diagnosis and diagnosis. 3. Discussion In China, breast cancer is the most frequent malignant tumor and the second leading cause of death among women, accounting for 31% of female tumors according to statistics. Early detection of breast cancer will greatly contribute to the control of cancer, thus facilitating the diagnosis and treatment of breast cancer when it is in an infiltrative state before it metastasizes. Some serum protein markers have been shown to be of great value in the diagnosis of breast tumors. The FDA has adopted tumor markers such as CA15.3 and CA27.29 and recommends that these two markers be used only for monitoring advanced breast cancer treatment or recurrence. The need for biomarkers that can be used alone or in combination with existing markers in the screening of breast cancer remains urgent. Protein fingerprinting technology is different from traditional tumor markers that can only be analyzed by a single indicator. Through dynamic and panoramic analysis of proteins, the smallest gene expression products (proteins or peptides) in the early stages of a patient’s disease are systematically analyzed to obtain information such as the content of various proteins and the molecular weight of proteins in the specimen to be examined, which is plotted as a protein fingerprinting profile (EPG) and compared with normal people, subnormal state, benign disease and cancer through computer software. By comparing and analyzing the differences with the fingerprint libraries of normal, subnormal, benign disease and cancer patients, new disease-related proteins can be detected and captured quickly, sensitively and specifically. The aim of this study was to investigate the value and significance of using serum protein fingerprinting to screen for serum markers of breast cancer for clinical diagnosis of breast cancer. The results of protein microarray showed that three proteins with statistically different expression peaks were found in breast cancer patients and normal patients, and their mass-to-charge ratios were 4800 Da, 6410 Da and 9300 Da, respectively, with 89.3% sensitivity and 92.7% specificity, showing that serum protein fingerprinting technology has reliable data for screening serum markers of breast cancer and can be applied to breast cancer It should be promoted.