Serum Proteomic Analysis Of Non-small Cell Lung Cancer

Objective To analyze the characteristic of serum proteins in non-small cell lung cancer ( NSCLC) patients of Fujian province, establish serum markers pattern for the diagnosis of NSCLC. To analyze epidermal growth factor receptor(EGFR) gene mutations in NSCLC patients of Fujian province and analyze the relationship between serum proteins and EGFR mutations.Methods Surface enhanced laser desorption ionization time of flight mass spectormetry( SELDI-TOF-MS ) technology was used to analyze serum samples including 34 cases of NSCLC patients and 34 cases of healthy controls. Biomarker Pattern Software (BPS) was used to detect the protein peaks significantly different between NSCLC patients and healthy controls. And then established a diagnostic pattern.This pattern was further valuated by a blind test. Fresh specimens of lung cancer and corresponding normal lung tissue were collected from 20 cases of NSCLC patients. After DNA extraction, nested polymerase chain reaction ( nested PCR )and direct deoxyribonucleic acid(DNA) sequencing were used to analyze EGFR gene mutations in NSCLC patients. Using SELDI-TOF-MS technology to analyze the alterations of serum proteins in NSCLC patients with EGFR mutations.Results Eleven significantly different protein peaks were found in serum samples between NSCLC patients and healthy controls. Five up-regulated protein peaks were identified with the relative molecular weights of 2959.77 Da,3209.05 Da,3286.37 Da,8000.69 Da,15982.85 Da(P<0.05). The sensitivity for diagnosing NSCLC was 91.18%,91.18%,85.29%,73.53% and 76.47% respectively.The specificity for diagnosing NSCLC was 82.35%,85.29%,75.53%,67.65%and 61.76% respectively . Six down-regulated protein peaks were identified with the relative molecular weights of 6221.60 Da,6459.09 Da,6651.87 Da,8590.69 Da,8719.24 Da,13804.88Da(P<0.05).The sensitivity for diagnosing NSCLC was 88.24%,91.18%,79.41%,76.47%,85.29% and 76.47 respectively .The specificity for diagnosing NSCLC was 79.41 %,88.24 %,85.29 %,76.47 %,79.41 % and 91.18 % respectively.Using BPS, a diagnostic pattern was established with 100% sensitivity and 94.12% specificity . A blind test generated a sensitivity of 94.74% and specificity of 90.00% respectively. No significantly different protein peak was found in serum samples of NSCLC patients with different pathological types , clinical stages and smoking history . SELDI-TOF-MS technology was used to analyze preoperative serum samples and postoperative serum samples in 15 cases of NSCLC patients.Two significantly up-regulated protein peaks were identified in postoperative serum samples with the relative molecular weights of 6137.16Da,9320.54 Da(P<0.05). SELDI-TOF-MS technology was used to analyze prechemotherapeutical serum samples and postchemotherapeutical serum samples in 30 cases of NSCLC patients. No significantly different protein peak was found in these two group of serum samples. EGFR mutations in tumors were identified from 3 of 20 (15%) patients,including 1 case of in-frame deletion in exon 19 and 2 cases of amino acid substitution in exon 21. There was no statistical difference in preoprative serum proteins between NSCLC patients with EGFR gene mutations and those with EGFR wild type (P>0.05) .Conclusion SELDI-TOF–MS technology can identify the significantly different protein peaks and establish a diagnostic pattern with high sensitivity and specificity. It will provide a highly accurate approach for the diagnosis of NSCLC. Significantly different protein peaks were identified between preoperative and postoperative serum samples in NSCLC. There was no significantly different protein peak in prechemotherapeutical serum samples and postchemotherapeutical serum samples of NSCLC patients. There was no significantly different protein peak in sera of NSCLC patients with different pathological types , clinical stages and smoking history .There was no significantly different protein peak in sera between NSCLC patients with EGFR gene mutations and those with EGFR wild type.