Tumor progression relies on the ability of cancer cells to effectively invade surrounding tissues and propagate. Among the many mechanisms that contribute to tumor progression is the epithelial-to-mesenchymal transition (EMT), a phenotypic plasticity phenomenon that increases the cancer cells' motility and invasiveness and influences their surrounding microenvironment by promoting the secretion of a variety of soluble factors. One such factor is IL-8, a chemokine with multiple pro-tumorigenic roles within the tumor microenvironment (TME), including stimulating proliferation or transformation of tumor cells into a migratory or mesenchymal phenotype. Further, IL-8 can increase tumor angiogenesis or recruit larger numbers of immunosuppressive cells to the tumor.

Prognostically, observations in many tumor types show that patients with higher levels of IL-8 at baseline experience worse clinical outcomes. Additionally, studies have shown that the chemokine directly contributes to the development of resistance to both chemotherapy and molecularly targeted agents. More recently, clinical studies evaluating levels of IL-8 in patients receiving immune checkpoint inhibition (ICI) therapy deduced that myeloid tumor infiltration driven by IL-8 contributes to resistance to ICI agents and that peripheral IL-8 can predict outcomes to ICI therapy. Further, pre-clinical data demonstrate that targeting IL-8 or its receptors enables improved tumor killing by immune cells, and treatment strategies combining blockade of the IL-8/IL-8R axis with ICI ultimately improve anti-tumor efficacy. Based on these results and the prognostic capacity of IL-8, there are a number of ongoing clinical trials evaluating the addition of IL-8 targeting strategies to immune-based therapies.

肿瘤进展依赖于癌细胞有效侵入周围组织并增殖的能力。在导致肿瘤进展的许多机制中，上皮间质转化 (EMT) 是一种表型可塑性现象，可增加癌细胞的运动性和侵袭性，并通过促进多种可溶性因子的分泌来影响其周围的微环境。其中一个因素是 IL-8，它是一种在肿瘤微环境 (TME) 中具有多种促肿瘤发生作用的趋化因子，包括刺激肿瘤细胞增殖或转化为迁移或间充质表型。此外，IL-8 可以增加肿瘤血管生成或向肿瘤募集更多的免疫抑制细胞。

预后方面，对许多肿瘤类型的观察表明，基线时 IL-8 水平较高的患者临床结果较差。此外，研究表明，趋化因子直接导致对化疗和分子靶向药物产生耐药性。最近，评估接受免疫检查点抑制 (ICI) 治疗的患者中 IL-8 水平的临床研究推断，由 IL-8 驱动的骨髓肿瘤浸润有助于对 ICI 药物的耐药性，并且外周 IL-8 可以预测 ICI 治疗的结果。此外，临床前数据表明，靶向 IL-8 或其受体能够提高免疫细胞对肿瘤的杀伤力，而将阻断 IL-8/IL-8R 轴与 ICI 相结合的治疗策略最终会提高抗肿瘤功效。