In murine PDAC models, chronic stress-dependent sympathetic nervesignalling triggers tumour growth via a feedforward loop, wherein adrenergicsignalling stimulates NGF, which promotes further innervation of tumour cellsvia axogenesis, resulting in increased noradrenaline accumulation in the tumourmicroenvironment, inducing β2-adrenergic receptor-dependent PDAC progression[168] (figure 11). Here, NGF is linked to neoplasm.