In this model, it appears that low doses of c-di-GMP significantly increased the production of IL-12 by myeloid-derived suppressor cells and improved antigen-specific T-cell responses, while high doses of c-di-GMP (range: 0.3–3 mmol/L) killed the 4T1 tumour cells directly by activating the tumour cell caspase-3 pathway [146]. The gene discussed is CASP3; the disease is neoplasm.