We then verified if the abundances of three canonical EMT markers in the proteomes of the discovery phase were associated with the sites from where the malignant cells were isolated: E-cadherin (CDH1), fibronectin (FN1), and vimentin (VIM) (11 matched FFPE tumor vs. metastasis; q > 0.05; two-sided unpaired Student’s t-test followed by Benjamini-Hochberg correction or proteins detected exclusively in one group; Supplementary Data 2-6). This evidence concerns the gene FN1 and neoplasm.