High Stromal TGFBI in Lung Cancer and Intratumoral CD8-Positive T Cells were Associated with Poor Prognosis and Therapeutic Resistance to Immune Checkpoint Inhibitors.

Background: We investigated whether the expression of transforming growth factor-beta-induced protein (TGFBI) and intratumoral immune cells including CD8- and Forkhead box protein P3 (Foxp3)-positive T cells in clinical lung cancer patients could predict the therapeutic response to nivolumab.

Methods: Thirty-three patients who were treated with nivolumab were enrolled in this study. Immunohistochemical analyses of TGFBI, PD-L1, CD8, Foxp3, and vimentin expression were conducted. Serum concentrations of TGFBI and transforming growth factor-beta1 (TGF-β1) were determined by enzyme-linked immunosorbent assay (ELISA).

Results: Cancer TGFBI was not associated with prognosis and therapeutic response to nivolumab, but cancer stromal TGFBI and intratumoral CD8-positive T cells were associated with them. Therefore, we evaluated cancer stromal TGFBI and intratumoral CD8-positive T cells. The high-TGFBI-expression group had poorer clinical responses than did the low-TGFBI-expression group (p < 0.0001). The number of times nivolumab was administered in the high-CD8-expression group was significantly higher than that in the low-CD8-expression group (p = 0.0046). The high-CD8-expression group had better clinical responses than did the low-CD8-expression group (p = 0.0013). Interestingly, all patients in the high-TGFBI/low-CD8-expression group had progressive disease (PD). In contrast, all patients in the low-TGFBI/high-CD8-expression group had PR + SD (partial response + stable disease) by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1).

Conclusions: The dual evaluation of stromal TGFBI and intratumoral CD8-positive T cells could be a useful predictive marker for nivolumab.