Besides the canonical proteins, this study identified 25 non-canonical protein isoforms from human plasma samples and 4 of these, FN1 (P02751-11), TPM3 (P06753-2), TPM1 (P09493-5), and NME2 (P22392-2), showed greater than 1.5-fold change decreases in RA with statistical significance (Supplementary Data S4). This evidence concerns the gene FN1 and rheumatoid arthritis.