Meanwhile, immunostaining of tumours with CD49 (high expression in NK cells, marked in red) and GPX4 (antioxidant systematized core regulatory enzyme, marked in green) were performed, the amount of NK cells was observed to increase significantly in the MCC group (Fig. 5f), and further increased after peptide conjugation and NIR treatment, which was probably associated with the alleviation of immunosuppression in the tumour microenvironment. This evidence concerns the gene GPX4 and neoplasm.