Fig. 1: Myeloid-specific deletion of Mettl3 in mice promotes B16 tumour growth and lung metastasis.

a–d B16 cells were subcutaneously injected into WT and Mettl3-null (KO) mice. B16 tumours were dissected and photographed (a). Tumour volume (b) (n = 6 mice per group), tumour weight (c) (n = 6 mice per group) and mouse survival (d) were recorded (WT group, n = 7 mice; KO group, n = 8 mice). e, f In vivo imaging of mice was conducted following intraperitoneal administration of a substrate (D-luciferin). Representative fluorescence images are shown (e) and were quantified (f) (n = 3 mice per group). g Representative images of tumours in mice injected with B16 tumour cells via the tail vein (upper panel) and representative HE staining images of lung sections (lower panel) are shown. h, i Quantification of the lung tumour diameter (h) and metastatic nodules (i) of the mice evaluated in (g) (n = 6 mice per group) was performed. j Representative Ki67 staining images of tumour sections are shown (left panel). Quantification of Ki67 expression was performed (right panel) (n = 5 mice per group). Scale bars: 100 μm. k The survival of mice injected with B16 tumour cells via the tail vein was documented (n = 8 mice per group). l Immunofluorescence staining for F4/80 and METTL3 was performed to analyse expression in normal and tumour tissues (left panel). Quantification of the expression of METTL3 in macrophages was performed (right panel). The white arrows highlight F4/80⁺ cells (n = 3 mice per group). Scale bars, 10 μm. Data are expressed as the mean ± SD. P values were determined by a two-tailed t-test (b, c, f, h, i, j and l) and the Gehan–Breslow-Wilcoxon test (d, k). *P ≤ 0.05, **P < 0.01 and ***P < 0.001. The source data are provided as a Source data file.