**1.3 Main application areas of serum peptidomics**

For the moment, the serum peptidomics is clinically used in complex diseases involved in polygene and featuring multi-cause heterogeneity, like cancer (including colon and rectal cancer, lung cancer, hepatic carcinoma, esophagus cancer, stomach cancer, cervical carcinoma and nasopharyngeal carcinoma), nerve degenerative diseases (including Alzheimer disease, Parkinson's disease, Huntington's Disease), autoimmune diseases (rheumatoid arthritis, system lupus erythematosus syndromes), cardio-cerebrovascular disease and palsy, to discover protein/polypeptide profiling and biomarker profiling as well as the single biomarker in the serum of sufferers of these diseases, making breakthroughs and providing a new tool for the researches of disease pathogeny, drug target, diagnosis and treatment.
