CD4 and posterior cortical atrophy: SNAP25 expression was negatively correlated with the purity of PCa (r = − 0.497, p < 0.01) and positively correlated with the abundance of several immune cell types, including B cells (r = 0.251, p < 0.01), CD4+ T cells (r = 0.404, p < 0.01), CD8+ T cells (r = 0.273, p < 0.01), neutrophils (r = 0.322, p < 0.01), macrophages (r = 0.452, p < 0.01), and dendritic cells (r = 0.382, p < 0.01).