Third, TSLP may drive tumour progression in breast- and pancreatic cancer21, 22 but also manifest tumour protective effects23, 24, 25, 26, while genetic rearrangements and mutations in the TSLPR gene (CRLF2) are found in paediatric acute lymphoblastic leukaemia (ALL)27. Here, CRLF2 is linked to acute lymphoblastic leukemia.