For each organ-specific cancer cohort, we first evaluated relative differences between cases and controls for three spiked-in recombinant proteins—SDF-1β, IGF1, and IGFBP7, each of which served as internal quality control and was spiked in at a ratio case/control respectively of 1:10, 1:1, and 10:1. The gene discussed is IGFBP7; the disease is cancer.