FOXP3 and neoplasm: In addition, genomic studies by other groups have shown that the Opn gene (Sppl) is one of the few significantly upregulated genes in stimulated Foxp3+ Tregs, and tumor-infiltrating Foxp3+ Tregs express higher levels of Spp1 compared to spleen and lymph node Foxp3+ Tregs [14,15,16].