IL1B and neoplasm: Thus, in order to determine the amount of tumour-derived IL-1β required for inhibition of tumour growth, B16F10-IL-1β and B16F10-vector cells were mixed at different ratios (0:1, 1:64, 1:16, 1:4 and 1:0) to obtain low to high levels of secreted cytokine (0, 17.8, 64.2, 328.6 and 1580.3 pg/ml, respectively in Fig 5D, left panel).