TGFBR2 and breast carcinoma: To further substantiate these results, we examined the well-established murine mammary tumor virus (MMTV)-polyoma middle T antigen (PyMT) transgenic mouse breast cancer model, crEVs were assessed for the presence of TβRII when the PyMT-induced tumors reached an average volume of 500, 1000 and 1500 mm3; The circulating EV-TβRII was found to increase proportionally with tumor size and also associated with the levels of metastasis (Fig. 2e and Supplementary Fig. 2a, b).