Type 2 innate lymphoid cells (ILC2) potentiate adaptive immune responses however whether
they have a role in mediating cancer immunity has not been assessed. Here, we report that mice genetically lacking ILC2s have significantly increased tumour growth rates and higher frequency of circulating tumour cells (CTCs) and metastasis to distal organs. Our data supports the conclusions that tumour-infiltrating ILC2s help mediate tumour immune-surveillance by
promoting adaptive T cells responses and that ILC2s play a hitherto undescribed role in
controlling metastasis. Furthermore, we demonstrate that adoptive transfer of ILC2s mediates a dramatic regression in cancer growth. Therefore, the adoptive transfer of ILC2s provides a new immunotherapeutic approach with the potential to aid in the eradication of cancers.