Reproducible and multiplex protein assays are greatly desired by cancer biologists as well as clinical oncologists to rapidly follow numerous proteins in clinical samples.We have now successfully applied magneto-nano bioehips based on giant magnetoresistance (GMR) spin valve sensor arrays and magnetic nanoparticle labels (nanotags) to the detection of biological events in the form of multiplex protein assays (4-to 64-plex) with great speed (0.5-2 hours), sensitivity (1 picogram/ml concentration levels or below), selectivity, and economy [1].The technology platform is well suited for longitudinal studies of animal or human cohorts after therapeutic intervention or radiation exposure [2].