Examination of TGFB2 mRNA expression in pediatric brainstem diffuse midline glioma (pbDMG) tumors showed that high TGFB2 mRNA levels were associated with an immunologically “cold” tumor microenvironment, characterized by low expression of antigen-presenting cell (APC) markers (e.g., CD14, CD163, ITGAX/CD11c), which impairs anti-tumor immune responses [28]. The gene discussed is TGFB2; the disease is diffuse midline glioma.