Directly quantifying TAM within a given VS may therefore carry predictive growth potential and in the first in vivo exploration of this it was demonstrated that compared to static tumours, growing VS displayed higher specific binding of a TSPO (translocator protein) PET tracer for inflammation [33]; with the source of this binding being an abundance of TSPO-expressing TAM (Fig. 1). This evidence concerns the gene TSPO and neoplasm.