TISIDB analysis of correlations between PITX1 and PITX2 expression and immune cell infiltration across human cancers. (A) The relationship between PITX1 expression and 28 types of TILs across various human cancers. (B) The top six TILs displaying the strongest Spearman’s correlation with PITX1 expression in HNSC. (C) The relationship between PITX2 expression and 28 types of TILs across various human cancers. (D) The top six TILs displaying the strongest Spearman’s correlation with PITX2 expression in HNSC. Act_CD8, activated CD8+ T cells; Tcm_CD8, central memory CD8+ T cells; Tem_CD8, effector memory CD8+ T cells; Act_CD4, activated CD4+ T cells; Tcm_CD4, central memory CD4+ T cells; Tem_CD4, effector memory CD4+ T cells; Tfh, T follicular helper cells; Tgd, gamma delta T cells; Th1, type 1 T helper cells; Th17, type 17 T helper cells; Th2, type 2 T helper cells; Treg, regulatory T cells; Act B, activated B cells; Imm_B, immature B cells; Mem_B, memory B cells; NK, natural killer cells; CD56bright, CD56bright NK cells; CD56dim, CD56dim NK cells; MDSC, myeloid derived suppressor cells; NKT, natural killer T cells; Act DC, activated dendritic cells; pDC, plasmacytoid DCs; iDC, immature DCs; Mast, mast cell.