a, Exosomal ITGβ4 levels in the plasma of mice bearing orthotopic 4175-LuT tumours, as a function of tumour progression. Blood plasma was collected for exosome isolation 6 weeks after intra-mammary fat pad tumour injection, then again 1 week after tumour resection, from mice that were deemed to be either free of tumour or presenting with recurring tumours based on IVIS bioluminescence imaging (n = 5 were pooled for each group, based on one experiment). For western blot source data, see Supplementary Fig. 1o. b, Exosomal ITGβ4 in healthy control subjects (Ctrl) (n = 13); patients with breast cancer (BrCa) and no metastasis (n = 3), liver metastasis (n = 1), or lung metastasis (n = 3); patients with rhabdomyosarcoma (RMS) and no metastasis (n = 1) or lung metastasis (n = 3); patients with pancreatic cancer (PDAC) with liver metastasis (n = 14) and lung metastasis (n = 3); and patients with melanoma (Mel) with lung metastasis (n = 2). c, Exosomal ITGαV in healthy control subjects (n = 13); patients with rhabdomyosarcoma and no metastasis (n = 1) or lung metastasis (n = 3); patients with breast cancer and lung metastasis (n = 3) or liver metastasis (n = 1); and patients with pancreatic cancer and liver metastasis (n = 15). Data are mean ± s.e.m. * P < 0.05; *** P < 0.001 by one-way ANOVA.