Thorpe et al. described that the homozygous deletion of phosphoinositide 3 kinase regulatory subunit 1 (PI3KR; gene encoding p85) is common in BC and results in p85 loss function, an increase in PI3K signalling and oncogenic transformation, thus, concluding that p85 had a role as a tumor suppressor [49]. The gene discussed is PIK3R1; the disease is breast cancer.