The anti-tumour activity of KPAR serum was associated with significant increases in the number of tumour-infiltrating natural killer (NK) cells, histologically quantified by NCR1 expression (Fig. 1h), as well as NK cells expressing CD16, the Fc receptor involved in antibody-dependent cellular cytotoxicity (ADCC), as quantified by flow cytometry (Fig. 1i). Here, NCR1 is linked to neoplasm.