Tumors lacking B2M grew moderately faster than wt tumors (mean tumor weight at d14 PK5L1940 42.8 mg PK5L1940 B2M−/− 90.8 p < 0.01) suggesting that although wt tumors have low basal MHCI, CD8 T cell immunosurveillance regulates tumor growth in this model. This evidence concerns the gene B2M and neoplasm.