目前，肺癌是全世界范围内最常见的恶性肿瘤之一，其发病率与死亡率均位于所有恶性肿瘤的前列。根据2024年中国国家癌症中心发布的最新癌症数据，肺癌每年新发病例高达106.06万，死亡病例约73.33万，高居所有恶性肿瘤首位，且近年来一直呈现出不断上升的趋势。因此，如何优化肺癌的诊疗现状，是当下临床亟待解决的难题。

肺癌主要包括非小细胞肺癌（non-small cell lung cancer，NSCLC）和小细胞肺癌，其中约有85%的病例均为NSCLC。近年来，针对NSCLC的综合治疗的手段不断发展，除手术治疗、放化疗和分子靶向治疗外，免疫治疗已经成为当下最具潜力的新型治疗手段，其中以抗PD-1/L1免疫治疗为基础的多种治疗方式，已经开始逐步革新NSCLC的传统治疗格局。然而，并非所有NSCLC患者都能从中获益，部分患者表现出原发性或继发性治疗耐药。本研究旨在探究NSCLC患者抗PD-1/L1免疫治疗耐药分子机制，筛选潜在联合治疗靶点，扩大NSCLC免疫治疗反应响应人群，为NSCLC患者的治疗提供更多的线索和依据，以期有效改善NSCLC患者的生活质量和临床预后。

本研究第一部分首先通过收集12例接受抗PD-1/L1免疫治疗的NSCLC患者治疗前基线组织样本进行转录组学和蛋白质组学检测，筛选出关键耐药分子FTH1，并通过免疫治疗临床组织样本进一步验证FTH1与抗PD-1/L1免疫治疗耐药密切相关。然后我们通过构建免疫缺陷和免疫健全小鼠肿瘤模型发现FTH1很可能通过重塑肿瘤免疫微环境导致免疫治疗耐药。同时，基于上清蛋白质组学、体内外功能实验、临床组织样本免疫组化等方法，我们发现FTH1一方面能抑制铁死亡介导的HMGB1释放；另一方面很可能通过调控CXCL16从而激活巨噬细胞PPAR通路，促进巨噬细胞M2型极化和趋化，从而减少CD8+T细胞浸润水平，塑造抑制型肿瘤免疫微环境，最终导致肿瘤免疫治疗耐药。最后我们利用分子虚拟筛选和结合最新研究报道，发现黄岑苷是FTH1的有效抑制剂，并通过小鼠肿瘤模型首次探究了黄岑苷和抗PD-1免疫治疗联用的治疗疗效和安全性，两者联用能够有效抑制肿瘤生长，同时对重要脏器无明显损伤，展现出可靠的安全性。

本研究第二部分继续探讨了FTH1在泛癌免疫治疗中的临床价值，通过多种生物信息学算法分析了FTH1在泛癌肿瘤免疫微环境中的全景图，并利用单细胞测序数据分析和多色免疫荧光染色方法验证了FTH1在泛癌肿瘤免疫微环境中的不同细胞中的表达模式。我们发现FTH1在多种肿瘤中显著高表达，同时FTH1高表达患者从免疫治疗中获益较少。此外FTH1与多种免疫细胞、免疫分子和免疫通路密切相关，尤其是与巨噬细胞的浸润和功能相关，并在肿瘤细胞和巨噬细胞中存在共表达模式。抑制FTH1相关的通路可能是一个潜在的泛癌免疫治疗耐药的思路。

综上所述，本研究发现FTH1很可能是NSCLC抗PD-1/L1免疫治疗的关键耐药分子，高表达FTH1的NSCLC患者难以从抗PD-1/L1免疫治疗中获益；其次本研究初步明确了FTH1在NSCLC中免疫治疗的耐药机制，FTH1很可能通过调控CXCL16促进M2型巨噬细胞极化和趋化，并能抑制铁死亡介导的HMGB1释放，从而影响CD8+T细胞浸润，塑造免疫抑制型肿瘤免疫微环境，最终导致NSCLC抗PD-1/L1免疫治疗耐药。重要的是，我们的研究结果表明抗PD-1免疫治疗和FTH1抑制剂黄岑苷联用很可能是一种全新的NSCLC患者的治疗方案，或许能够给未来NSCLC患者的治疗带来一些全新的线索和依据。此外，我们还发现FTH1很可能与泛癌免疫治疗抵抗相关，FTH1在多种肿瘤类型中与巨噬细胞浸润相关，并与多种免疫分子和免疫通路密切相关，FTH1抑制剂黄岑苷或许能够有效改善泛癌免疫治疗耐药的难题。

Lung cancer is one of the most common malignant tumors worldwide, and its incidence and mortality rates are at the top of all malignancies. According to the latest cancer data released by the National Cancer Center of China in 2024, lung cancer has a high incidence rate of 1,060,600 new cases and 733,300 deaths per year, which is the highest among all cancers, and has been showing a rising trend in recent years. Therefore, how to optimize the diagnosis and treatment of lung cancer is an urgent clinical problem to be solved.

Lung cancer mainly includes non-small cell lung cancer (NSCLC) and small cell lung cancer, and about 85% of the cases are NSCLC. In recent years, the comprehensive treatment of NSCLC has been developing continuously, and in addition to surgery, radiotherapy, chemotherapy, and molecular targeting therapy, immunotherapy has become the most promising new treatment method, in which a variety of treatment modalities based on anti-PD-1/L1 immunotherapy have begun to gradually revolutionize the traditional treatment pattern of NSCLC. However, not all NSCLC patients can benefit from this therapy, and some of them show primary or secondary treatment resistance. The aim of this study is to investigate the molecular mechanisms of anti-PD-1/L1 immunotherapy resistance in NSCLC, to screen for potential combination therapy targets, to expand the population of NSCLC immunotherapy responders, and to provide more clues and rationale for the treatment of NSCLC patients.

Firstly, we screened out the key resistance molecule FTH1 by collecting pre-treatment baseline tissue samples from 12 NSCLC patients receiving anti-PD-1/L1 immunotherapy for transcriptomic and proteomic detection, and verified that FTH1 is closely related to anti-PD-1/L1 immunotherapy resistance by clinical tissue samples. Then we found that FTH1 and may lead to immunotherapy resistance by remodeling the tumor immune microenvironment by constructing an immunodeficient mouse tumor model and an immune-sound mouse tumor model. Meanwhile, based on supernatant proteomics, ex vivo and in vivo functional experiments, and immunohistochemistry of clinical tissue samples, we found that FTH1 likely shapes the suppressive tumor immune microenvironment by modulating CXCL16 and thus activating the PPAR signal pathway, promoting macrophage M2-polarization and chemotaxis, inhibiting ferroptosis-mediated HMGB1 release, and can reduce the level of CD8+ T-cell infiltration, which ultimately leads to immunotherapy resistance. Finally, using molecular virtual screening and combining with the latest research reports, we found that baicalin is an effective inhibitor of FTH1, and explored the therapeutic efficacy and safety of the combination of baicalin and anti-PD-1 for the first time in mouse models, and the combination of the two was able to effectively inhibit tumor growth without any significant damage to vital organs, demonstrating a reliable safety profile.

Then, we explored the clinical value of FTH1 in pan-cancer immunotherapy by various bioinformatics algorithms, and verify the expression pattern of FTH1 in different cells in the pan-cancer tumor immune microenvironment based on the single-cell sequencing data analysis and multi-color immunofluorescence staining methods. We found that FTH1 was significantly overexpressed in a variety of tumors, while patients with high FTH1 expression benefited less from immunotherapy. In addition, FTH1 is closely associated with a variety of immune cells, immune molecules and immune pathways, especially with macrophage infiltration and function, and is mostly expressed in tumor cells, with co-expression patterns in macrophages. Inhibition of FTH1-related pathways is likely to be a potential idea for pan-cancer immunotherapy resistance.

In summary, we found that FTH1 is likely to be a key resistance molecule for anti-PD-1 immunotherapy in NSCLC, and NSCLC patients with high expression of FTH1 are difficult to benefit from anti-PD-1/L1 immunotherapy; secondly, this study preliminarily clarified the mechanism of immunotherapeutic resistance to FTH1 in NSCLC, and FTH1 is likely to inhibit ferroptosis-mediated HMGB1 release，and promote M2-type macrophage polarization and chemotaxis by regulating CXCL16, which then affects CD8+ T cell infiltration and participates in shaping the immunosuppressive tumor immune microenvironment, ultimately leading to anti-PD-1/L1 immunotherapy resistance in NSCLC. Importantly, our findings suggest that the combination of anti-PD-1/L1 immunotherapy and the FTH1 inhibitor baicalin is likely to be a novel therapeutic regimen for patients with NSCLC, and may be able to bring some new clues and rationale for the treatment of NSCLC patients in the future. In addition, we found that FTH1 is likely to be associated with pan-cancer immunotherapeutic resistance; which is correlated with macrophage infiltration, immune molecules, and immune pathways in a variety of tumor types, and the FTH1 inhibitor (baicalin) may be effective in ameliorating the challenge of pan-cancer immunotherapeutic resistance.