Among the top 25 upregulated genes in the carious pulp set was Serum Amyloid A1 (SAA1) gene (Supplementary Table 2), an acute-phase protein produced in response to tissue injury, inflammation and cancer.20 This gene was specifically upregulated in the fibroblast population within the stromal cluster (Supplementary Table 2) that was marked by increased proportion of cells expressing genes associated with activated Transforming Growth Factor beta (TGFβ), Tumour Necrosis Factor (TNF) and Nuclear Factor Kappa B (NFκB) signalling pathways (Fig. 4a). Here, SAA1 is linked to cancer.