p110α is essential for tumor driven by PIK3CA mutations and is also activated in tumors harboring alterations in RTKs and RAS; p110β seems to be the main isoform involved in PI3K signaling in tumor presenting PTEN deficiencies; and p110δ, a key PI3K isoform for B-cells development, is crucial for lymphomas [29]. The gene discussed is PTEN; the disease is lymphoma.