Clusterin, fibulin-1, vitronectin, complement component C9, three collagen proteins, as well as the well-known amyloid signature proteins apolipoprotein E, apolipoprotein A4, and serum amyloid P were discovered as novel “amyloid signature” proteins using a Boruta method applied on a random forest classifier to proteomics data obtained from the mass spectrometric analysis of Congo-red-positive amyloid-containing biopsies and Congo-red-negative biopsies in order to train an SVM learning system. The gene discussed is APOA4; the disease is amyloidosis.