Purpose The efficacy of immunotherapy for non-small cell lung cancer (NSCLC) is limited owing to cold tumors and drug resistance. Therefore, it is important to identify the molecular mechanisms underlying immune evasion in NSCLC. Spontaneous ferroptosis of neutrophils has been suggested as a key mechanism of immunosuppression in cancer. Insulin-like growth factor binding protein 1 (IGFBP1) plays an important role in immune infiltration in several cancers. However, the role of IGFBP1 in NSCLC is unknown. Therefore, in this study, we aimed to investigate the association of IGFBP1 mRNA expression with infiltration of myeloid-derived suppressor cells and prognosis in NSCLC. Patients and Methods Retrospective RNA-seq data from 990 patients in the Cancer Genome Atlas (TCGA) database were analyzed in relation to patient clinical characteristics. The Timer2 database was used to assess immune infiltration, and the FerrDb V2 database was used to obtain ferroptosis-related genes. Finally, the results were validated by the proteomic analysis of serum samples collected from six patients with NSCLC and six healthy individuals. Results IGFBP1 expression was enriched in lung adenocarcinoma samples and positively correlated with the pathological grade of NSCLC. IGFBP1 expression was an independent prognostic factor for the overall survival of patients with NSCLC. In addition, IGFBP1 expression correlated with myeloid-derived suppressor cell infiltration. Notably, Gene Ontology analysis of IGFBP1 -related genes revealed that the major molecular functions of their protein products were related to NADP + 1-oxidoreductase activity. Furthermore, expression levels of multiple ferroptosis suppressor genes positively correlated with IGFBP1 expression. Conclusion High IGFBP1 expression indicates a poor prognosis in patients with NSCLC, which may be related to tumor immunosuppression caused by neutrophil ferroptosis.

Immune checkpoint inhibitor (ICI)-related chronic pneumonitis is rare. Limited information is available on the characteristics of this condition. Herein, we present the case of a 54-year-old man with recurrent severe ICI-related pneumonitis. The patient developed fever and dyspnea during both episodes of pneumonitis. He had been previously diagnosed with gastric signet ring cell carcinoma and was undergoing treatment with an anti-PD-1 combination chemotherapy regimen. We reviewed previous case reports of ICI-related pneumonitis according to the primary cancer, time of onset in relation to ICI therapy and chest imaging findings. ICI-related pneumonitis can progress to chronic pneumonitis. Repeated computed tomography imaging showing lung changes in the same location may help to make the diagnosis.