PIK3R1 (Phosphoinositide-3-Kinase, Regulatory Subunit 1): PIK3R1 is a gene that encodes a regulatory subunit of phosphoinositide 3-kinase (PI3K), an essential component in signalling pathways that control 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 signalling and is associated with diabetes and metabolic syndromes.