PIK3R1 (Phosphoinositide-3-Kinase, Regulatory Subunit 1): PIK3R1 is a gene that encodes a regulatory subunit of phosphoinositide 3-kinase (PI3K), a key component in signaling pathways that regulate cell growth, proliferation, and survival. Mutations in PIK3R1 are linked to various cancers and serve as targets for cancer therapies. Additionally, it plays a role in insulin signaling and is associated with diabetes and metabolic syndromes.