PKN1 and breast cancer: This GRPM contains seven genes: ARHGAP10, CCNT2, CDR2, HEXIM1, NEUROD2, PKN1, and ZFAND6. ARHGAP10 (rho GTPase Activating Protein 10) was previously reported as the most significant locus (P = 2.3 × 10−7) in a GWAS of breast cancer survival14.