Previous studies have demonstrated that naftopidil has higher affinity for the α1d-adrenergic receptor than for the α1a- and α1b-adrenergic receptor subtypes [30], and in Japan it is one of the most widely used α1-adrenergic receptor antagonists for the treatment of benign prostatic hyperplasia (BPH) [31,32]. Here, SERPINA1 is linked to benign prostatic hyperplasia.