Two-dimensional gel analysis of protein expression profile in squamous cervical cancer patients

Screening in cervical cancer is progressing to find out candidate genes and proteins, which may work as biological markers and play a role in tumor progression. We examined the protein expression patterns of squamous cell carcinoma (SCC) tissues from Korean women using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of fight (MALDI-TOF) mass spectrometer. Normal cervix and SCC tissues were solubilized and 2-DE was performed using the pH 3–10 linear IPG strips of 17 cm length and silver stained. Protein expression was evaluated using PDQuest 2-D software™. The differentially expressed protein spots were identified with MALDI-TOF mass spectrometer and the peptide mass spectra identification was performed using Mascot program searching the Swiss-prot or NCBInr databases. A total of 35 proteins were detected in SCC. 17 proteins were up-regulated and 18 proteins were down-regulated. Among the proteins identified, 12 proteins (pigment epithelium derived factor, annexin A2 and A5, keratin 19 and 20, heat shock protein 27, smooth muscle protein 22 alpha, α-enolase, squamous cell carcinoma antigen 1 and 2, glutathione S-transferase, apolipoprotein a1) were previously known proteins involved in tumor and 21 proteins were newly identified in this study. 2-DE offers total protein expression profiles of SCC tissues and further characterization of proteins that are differentially expressed will give a chance to identify tumor-specific diagnostic markers for SCC.