The use of chimera proteins constructed using the extracellular domain of NKp30, NKp44, or NKp46 fused to the Fc immunoglobulin domain (NCR-Fc) or to an amino-terminal isoleucine zipper (NCR-ILZ) allowed to analyze the expression of NCR ligands on tumor cells. The gene discussed is NCR1; the disease is neoplasm.