We then analysed Opn expression in fractions that had been depleted of adipocytes by centrifugation, leaving tumour cells and stromal vascular cells, and confirmed that Opn expression was upregulated in the tumours of the HFD-fed PyMT mice compared with the tumours of the ND-fed PyMT mice (Fig. 1d). The gene discussed is SPP1; the disease is neoplasm.