RNA sequencing of the LCT-MF and non-LCT MF lesional skin revealed that among the activated pathways regulating large cell transformation, the expression of the genes NR4A2 (p < 0.01), MYC (p < 0.01), ICOS (p < 0.001), CDK1 (p < 0.05), PD-L1 (p < 0.01), PD1 (p < 0.001), NF-κB (p < 0.05), and E2F1 (p < 0.05) were significantly upregulated in MF-LCT (Figure 4B). Here, ICOS is linked to mycosis fungoides.