An alternative method for the proteomics approach was applied by Im et al. They used matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF/MS) analysis to compare the protein profiles of 5 patients with achalasia and 5 healthy individuals, identifying 28 protein spots up-regulated in patients, including complement C4B5, C5 and C3, cyclin-dependent kinase 5, transthyretin and alpha 2 macroglobulin. The gene discussed is C3; the disease is Achalasia.