GRB2 and posterior cortical atrophy: Among most dramatically dysregulated protein complexes, the GRB2-SOS1 complex has significantly higher (Z score difference = 1.57, q = 0.017) assembly level, whereas the PPP2CA-PPP2R1A complex has significantly lower (Z score difference = − 1.64, q = 0.009) assembly level, in high-grade PCa than in low-grade PCa.