We used membrane-impermeable Sulfo-NHS-SS-biotin labeling of intact sgControl (sgCTL, sgC) and sgMAP4K4 (MAP4K4 knockout, sgM4, Fig S1A and B) MB tumor cells, followed by streptavidin protein capture and high-resolution mass spectrometry analysis (Fig 1A). The gene discussed is MAP4K4; the disease is neoplasm.