PVR and fibrosarcoma: qRT-PCR revealed that the levels of mRNA for the proinflammatory cytokines Ifng, Il1b, and Il12b and the anti-inflammatory cytokine Il10 in fibrosarcomas induced by 5 μg MCA were similar in WT and CD155-deficient mice in both C57BL/6N and BALB/c backgrounds (Fig. 2).