Characteristics of the immune microenvironment and their clinical significance in non-small cell lung cancer patients with ALK-rearranged mutation

Abstract

BackgroundAlthough immune checkpoint inhibitors (ICIs) are one of the most important treatments for advanced-stage non-small-cell lung cancer (NSCLC), NSCLC patients with ALK-rearranged usually don’t obtain a clinical benefit. The reason may be related to the unique tumor microenvironment (TME). We evaluated the characteristics of immune biomarkers of the TME and their prognostic value in ALK-rearranged NSCLC.MethodsTumor samples from patients with ALK-rearranged (N = 39) and EGFR- (N = 40)/KRAS- (N = 30) mutated NSCLC were collected. Immunohistochemistry (IHC) was used to assess the expression of 9 tumor immune markers as well as 6 immune markers of tumor-infiltrating cells. To research the TME of ALK-rearranged NSCLC, EGFR/KRAS-positive patients were used as controls. Furthermore, the correlation between the efficacy and prognosis of patients with advanced-stage (IIIC-IV) ALK rearrangements treated with targeted drugs was analyzed in terms of the TME.ResultsThe proportion of PD-L1+ tumors was lower in ALK-positive NSCLC than in KRAS-positive NSCLC. Besides, the proportion of T cells expressing TIM-3-CD8+ (15.38%), CTLA4-CD8+ (12.82%), LAG3-CD8+ (33.33%) and PD-1-CD8+ (2.56%) in ALK-positive NSCLC was lower than that in EGFR/KRAS-positive NSCLC. The expression of CD3, CD8 T cells and CD20 B cells was lower in ALK-positive NSCLC than in KRAS-positive NSCLC (p < 0.0001, < 0.005, and < 0.001, respectively). Nevertheless, the level of CD4 helper T cells was higher in ALK-positive NSCLC than in EGFR/KRAS-positive NSCLC (p < 0.0001 and p < 0.05, respectively). The repression of TIM3 was higher in ALK-positive NSCLC than in KRAS-positive NSCLC (p < 0.001). In addition, our data showed that high expression of PD-L1 (HR = 0.177, 95% CI 0.038–0.852, p = 0.027) and CTLA4 (HR = 0.196, 95% CI 0.041–0.947, p = 0.043) was related to lower OS in advanced-stage ALK- rearranged NSCLC patients treated with ALK tyrosine kinase inhibitors (TKIs).ConclusionsImmunosuppressive status was characteristic of the TME in patients with ALK-positive NSCLC compared with EGFR/KRAS-positive NSCLC. High expression of PD-L1 and CTLA4 was an adverse prognostic factor in advanced-stage ALK-rearranged NSCLC patients treated with ALK-TKIs. Immunotherapy for ALK-rearranged patients requires further exploration and validation by clinical trials.

Narrative review: immunotherapy in anaplastic lymphoma kinase (ALK)+ lung cancer—current status and future directions

“…However, this difference in T reg cells was not seen by IHC in a cohort of 39 patients with ALK+ NSCLC ( 70 ). Within the cohort of 39 patients with ALK+ NSCLC, CD8 + T cell expression of checkpoints PD-1, CTLA-4, lymphocyte activating gene 3 (Lag3), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) by IHC was markedly reduced ( 70 ). This suggests infiltrating CD8 + T cells were unable to engage with potential tumor antigens as T cell checkpoint expression is upregulated by T cell activation ( 72 ).…”

“…Comparative mRNA studies of 31 samples from ALK+ NSCLC patients who were treatment naïve found an increase in T regulatory (T reg ) cells within the ALK+ NSCLC TME compared to patients with EGFR+ NSCLC or patients with ALK− and EGFR− NSCLC (71). However, this difference in T reg cells was not seen by IHC in a cohort of 39 patients with ALK+ NSCLC (70). Within the cohort of 39 patients with ALK+ NSCLC, CD8 + T cell expression of checkpoints PD-1, CTLA-4, lymphocyte activating gene 3 (Lag3), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) by IHC was markedly reduced (70).…”

“…Modified versions of IL-2, a major driver of T cell response, are able to bind with high affinity to effector T cells and are unable to interact with the IL-2 receptor present on T reg cells (92). Modified IL-2 may promote the acquisition of effector functions of T cells already present in the ALK+ NSCLC TME while avoiding driving proliferation and function of T reg cells that have also been identified in the ALK+ NSCLC TME (16,45,61,(68)(69)(70)(71)77,78). A phase I study of modified IL-2 plus nivolumab, including 5 patients with treatment-naïve, metastatic NSCLC, showed an increase in TME CD8 + T cells on treatment and no increase in T reg cells (93).…”

“…A major difference was noted in levels of interferon-γ transcript within the CD8 + T cells where control tumors contained CD8 + T cells that were positive for interferon-γ mRNA, but in ALK+ NSCLC CD8 + T cells were negative for interferon-γ mRNA suggesting an ineffective effector T cell response ( 69 ). In comparison to KRAS mutation positive NSCLC, IHC of tumor specimens from 39 patients with ALK+ NSCLC demonstrated fewer infiltrating CD3 + and CD8 + cells and reduced levels of granzyme B, which may suggest reduced T cell activity but could reflect reduced T cell numbers overall ( 70 ). Comparative mRNA studies of 31 samples from ALK+ NSCLC patients who were treatment naïve found an increase in T regulatory (T reg ) cells within the ALK+ NSCLC TME compared to patients with EGFR+ NSCLC or patients with ALK− and EGFR− NSCLC ( 71 ).…”

Spoilt for choice: different immunosuppressive potential of anaplastic lymphoma kinase inhibitors for non small cell lung cancer

“…The tumor microenvironment of ALK-positive NSCLC has been demonstrated to be immunosuppressive ( 13 ). It has been reported that Crizotinib can stimulate immunogenic cell death ( 14 , 15 ), which might mediate the induction of potent anti-tumor immune responses.…”