KLK2 and posterior cortical atrophy: Specifically, we compared the expression levels of both LE and club cell markers among cluster 0, other club cells, and the LE population within the PCa samples, and found that club cell cluster 0 exhibited higher expression of LE markers KLK2, KLK3, ACPP, and NKX3-1 than other cell states (Fig. 3h) while AR itself was not upregulated in cluster 0 (Supplementary Fig. 3d), and that expression of club markers PIGR, MMP7, CP, and LTF in all club cells was significantly higher than in the LE population (Fig. 3h).