Using several functional assays including multiple ligand-inducible LAIR1 chimeric receptor reporter assays, the analyses of immune cell activities of human cells including those from cancer patients, human LAIR1 transgenic mice, and the humanized xenograft tumor model, we demonstrate that active blocking LAIR1 signaling with the LAIR1 antagonist antibody can activate anti-tumor function of multiple immune cells and inhibit tumor development. This evidence concerns the gene LAIR1 and neoplasm.