Tumor-associated NK cells, a subset of NK cells characterized as dysfunctional due to decreased cytotoxic molecule expression, possess higher NR4A1 expression, and this is similar to the high expression of exhausted CD8+ T cells in tumor-infiltrating lymphocytes; however, the underlying mechanism of how NR4A1 leads to this dysfunctional phenotype is not understood [16]. Here, NR4A1 is linked to neoplasm.