Differential expression and clinical significance of serum protein among patients with clear-cell renal cell carcinoma

BACKGROUND AND OBJECTIVE: Looking for tumor markers by using protein chip technology is one of the hot topics, but many studies are still limited on short term detection of differential expressed proteins before and after surgery among patients with RCC. This study analyzed differential expressed serum protein and its clinical significance with clear-cell renal cell carcinoma to further measurement of the rule of variable expressing. METHODS: Eighty-nine patients with clear-cell renal cell carcinoma who underwent surgery from November 2013 to 2014 and postoperatively confirmed by pathology were entered in RCC group, 100 healthy volunteers and patients without RCC who underwent medical examination in the same period were entered in control group. The serum protein were analyzed in both group before surgery and every regular follow-up period in 1 year after surgery with RCC group. The surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS) and weak cation exchange protein chip (CM10) technology systems were used for identifying differential expressed serum protein in RCC group and controls. The linear support vector machine (SVM) was applied to establish the diagnostic model of protein fingerprints and the leave-one-out cross validation was used for determining model discriminating effect. The differential expressed proteins were analyzed by ZUCI-PDAS protein spectral data analysis system. RESULTS: Five kinds of proteins were identified as potential biomarker, ultimately. The M/Z of these proteins was 15953, 7987, 9304, 8948, 5911, respectively. There were significant difference on expression level of these proteins with two groups preoperatively (P < 0.05). Comparison of all postoperative expression levels to preoperative one and each differential level mutually between a year in postoperative period also revealed statistical significance (P < 0.05). With taking identified proteins as biomarker, the sensitivity and specificity in predicting clear-cell renal cell carcinoma was 88.8% (79/89) and 91.0% (91/100), respectively. CONCLUSION: The corresponding specific protein was Bcl-2 family apoptosis regulatory proteins, WAP four-disulfide core protein, Krueppel-like factor 8, monocyte chemotactic protein-1, serum amyloid beta-protein-4, respectively, and will may serve as tumor markers of kidney cancer. These proteins manifests high predictive value for clear-cell renal cell carcinoma, and may contribute to therapeutic evaluation, prognosis and targeted therapy for clear-cell renal cell carcinoma.