B2M and cancer: Although IFNγ receptors were not up-regulated in SBS and SBM conditions, Beta-2-microglobulin (B2M), a downstream target of IFNγ signaling, was 9.03 fold up-regulated in BALB/c tumors relative to 2D cultures, a > 3.5X increase above all other condition (Figure 5I), suggesting that cancer cells significantly up-regulate the IFNγ pathway under syngeneic conditions.