Lysophosphatidylinositol signalling: New wine from an old bottle

► LPI regulates diverse physiological and pathophysiological processes. ► GPR55 is a specific and a functional receptor of LPI. ► LPI/GPR55 axis plays a role in physiological and pathological contexts. ► LPI and GPR55 are relevant for the proliferation and migration of cancer cells. ► LPI/GPR55 axis could be a possible therapeutic target.