We aimed to analyze the effect of the TLR3 L742F variant in the TLR3-deficient P2.1 fibrosarcoma cell line, which does not produce detectable amounts of TLR3 protein and does not respond to the dsRNA mimic polyinosinic:polycytidylic acid (poly[I:C]) [32]. The gene discussed is TLR3; the disease is fibrosarcoma.