OX-40 knockout CTCL cells engrafted into the chick embryo model resulted in a significant reduction in tumor weight (28% in MyLa embryos, p < 0.0001; 40% in SeAx embryos, p < 0.0001; Figure 2A) compared with mock CTCL cells, indicating the critical role of OX-40 in tumor progression. Here, TNFRSF4 is linked to neoplasm.