KLRD1 and cancer: In contrast to the MHC class Ia, numerous studies have now found that HLA-E as well as HLA-G are enriched in various types of cancer.128–131 Tumors with either upregulated HLA-E or dually upregulated HLA-E and HLA-G are associated with poorer clinical outcome in patients.129 Importantly, our group recently demonstrated a significant correlation between HLA-E-enriched tumors with CD94/NKG2a-enriched TILs, in four different cancer types.40 This suggest that CD94/NKG2a and HLA-E could negatively affect antitumor TILs responses.