Aim: Detection of novel tumor biomarker will aid in diagnosis of early-stage small cell lung cancer (SCLC). The purpose of this study was to identify novel tumor biomarker in serum from patients with SCLC using a proteomics-based approach.
Methods: Sera were analyzed before the initiation of chemotherapy. Serum proteins of SCLC patients and healthy controls were collected and separated by 2-D fluorescence differential gel electrophoresis (2-D DIGE). Positive spots were analyzed by LC-MS/MS. Different expression of identified biomarker was verified by immunohistochemical method in wax specimen from 40 patients.
Results: A total of 86 proteins were shown to be differentially abundant between the serum of SCLC patients and normal subjects by 2-D DIGE. Fifteen proteins were identified by LC-MS/MS. According to the bioinformatic analysis, these proteins are mainly involved in development and carcinogenesis. Some of them have been previously demonstrated to be important prognostic factors. Differential expression of 5 proteins between the normal tissue and cancerious tissue was confirmed by immunochemistry of SCLC patients.
Conclusion: We have identified different serum proteins between SCLC patients and healthy controls. These proteins may be potential serum biomarkers for early detection of SCLC and play a role in the development and metastasis of SCLC.