**5. Clinical applications for proteoform identification**

Several studies are carried out aiming to find markers for pathophysiology process of Alzheimer's disease (AD), cancer [86], type 2 diabetes, and chronic alcohol abuse, among other diseases. The identification of proteoforms associated with different diseases will undoubtedly be an essential dividing mark for early diagnosis, prevention and treatment. Some examples for proteoform identification applications as apolipoproteins proteoforms, B-type natriuretic peptide (BNP), disorders of glycosylation, detection of structural changes in transthyretin, hemoglobin proteoforms, cystatin C-truncated proteoforms, C-reactive protein, vitamin D-binding protein, transferrin and immunoglobulin G (NISTmAb) were discussed [86, 87]. In the last 30 years, since the MALDI and ESI approaches were developed, only about a dozen of mass spectrometry protein identification tests have been described. Here, we present studies involving Alzheimer's disease and alterations in the levels of apolipoproteins associated with lipid metabolism.
