PAGE4 and posterior cortical atrophy: To further validate key C1-C3 delineating markers in clinical PCa at the protein level and provide spatial context, patient tissues were immunostained for the SMC markers CNN1, CCDC102B or SMA (encoded by ACTA2), the C1/C2 marker PAGE4, C2 marker CES1 and C3 markers ITGA11 or ENG (Fig. 3, Supplemental Fig. S10).