Among proteins correlating with response, we prioritized JPT1 for further validation as this protein exhibited the greatest fold‐change difference in pre‐metformin treatment biopsies from responders vs nonresponders (log2 ratio = 3.84, edgeR P‐value = 9.78E−06), and was decreased in abundance in post‐ vs pretreated tumor tissues in metformin responders (log2 ratio = −1.06, edgeR P‐value = .0201), but remaining largely unaltered in nonresponders (Figure 2). The gene discussed is JPT1; the disease is neoplasm.