STAT3 and anaplastic large cell lymphoma: In ALK-positive ALCL, cellular components involved in the downstream signalling of ALK include the Janus kinase 3 (JAK3) / signal transducer and activator of transcription 3 (STAT3) and interacting partners; and phospholipase C (PLC-γ) and secondary messengers together with class-Ia phosphoinositide 3-kinase (PI3K) / protein kinase B (AKT).