TGFB1 and neoplasm: TGF-β is produced by inter alia T cells, and has wide-ranging effects on tumour or parasite development: it promotes primary tumour growth and tumour metastasis by suppressing anti-tumour T cell function, suppresses the immune response to maintain worm burden through pathways involving TGF-β production, and maintains worm fecundity by influencing TGF-β activity (Doligalska et al. 2006; Li and Flavell 2008).