Cancer is characterized by a high fatality rate, complex molecular mechanism, and costly therapies. The microenvironment of a tumor consists of multiple biochemical cues and the interaction between tumor cells, stromal cells, and extracellular matrix plays a key role in tumor initiation, development, angiogenesis, invasion and metastasis. To better understand the biological features of tumor and reveal the critical factors of therapeutic treatments against cancer, it is of great significance to build in vitro tumor models that could recapitulate the stages of tumor progression and mimic tumor behaviors in vivo for efficient and patient-specific drug screening and biological studies. Since conventional tissue engineering methods of constructing tumor models always fail to simulate the later stages of tumor development due to the lack of ability to build complex structures and angiogenesis potential, three-dimensional (3D) bioprinting techniques have gradually found its applications in tumor microenvironment modeling with accurate composition and well-organized spatial distribution of tumor-related cells and extracellular components in the past decades. The capabilities of building tumor models with a large range of scale, complex structures, multiple biomaterials and vascular network with high resolution and throughput make 3D bioprinting become a versatile platform in bio-manufacturing as well as in medical research. In this review, we will focus on 3D bioprinting strategies, design of bioinks, current 3D bioprinted tumor models in vitro classified with their structures and propose future perspectives.

中文翻译：

---

基于3D生物打印的体外肿瘤模型的构建

癌症的特点是高死亡率，复杂的分子机制和昂贵的疗法。肿瘤的微环境由多种生化线索组成，肿瘤细胞，基质细胞和细胞外基质之间的相互作用在肿瘤的发生，发展，血管生成，侵袭和转移中起着关键作用。为了更好地了解肿瘤的生物学特征并揭示针对癌症的治疗方法的关键因素，建立体外肿瘤模型可以概述肿瘤发展的各个阶段，并在体内模拟肿瘤行为，以实现有效的和针对患者的特异性具有重要意义。药物筛选和生物学研究。由于缺乏构建复杂结构和血管生成潜力的能力，传统的构建肿瘤模型的组织工程方法始终无法模拟肿瘤发展的后期阶段，因此三维（3D）生物打印技术已逐渐在肿瘤微环境建模中得到应用在过去的几十年里，肿瘤相关细胞和细胞外成分的准确组成和组织良好的空间分布。建立具有大规模，复杂结构，多种生物材料和高分辨率和高通量血管网络的肿瘤模型的能力使3D生物打印成为生物制造和医学研究的多功能平台。在这篇评论中，我们将重点介绍3D生物打印策略，生物墨水的设计，