Bunse et al. reported that non-cell-permeable tumor-derived R-2HG can be taken up by human CD8+ T cells through the sodium-dependent dicarboxylate transporter 3 (SLC13A3) and that R-2HG accumulation in CD8+ T cells suppresses proliferation and anti-tumor activity.37 Notarangelo et al. showed that the effect of non-cell-permeable R-2HG on the impairment of CD8+ T cells is transient and relies on inhibiting the LDH enzyme.19 Conversely, Bottcher et al. failed to detect impaired CD4+ or CD8+ T cell proliferation or increased cell death when cells were cultured with R-2HG. This evidence concerns the gene CD4 and neoplasm.