STING1 and neoplasm: To test whether PC7A NPs prolong STING activation in vivo, we intratumourally injected cGAMP (50 μg), PC7A NPs (50 μg) and cGAMP-loaded PC7A NPs (2.5 μg/50 μg) into MC38 tumours (~100 mm3) and measured the expression of interferon-stimulated genes in both tumours and the draining lymph nodes over time.