转移癌症很难检测和治疗，并导致大多数与癌症相关的死亡。相对缺乏针对转移癌的治疗方案代表了一项重要的未满足临床需求。细胞外基质（ECM）在原发性和转移性肿瘤中均形成肿瘤微环境的主要组成部分，并且某些ECM蛋白可以在肿瘤中选择性地和丰富地表达。针对在转移癌中显示选择性丰度的ECM蛋白的纳米抗体具有作为成像和治疗载荷传递的潜力。在这里，我们描述了一种策略，使用作为免疫原的来自三阴性乳腺癌（TNBC）和结肠直肠癌（CRC）转移部位的整个ECM富集制剂，来开发针对人转移癌中表达的ECM蛋白的噬菌体展示库的方法。同时，基于LC-MS / MS的蛋白质组学用于定义由TNBC和CRC的转移体共享的转移相关ECM谱系，这一保守的ECM蛋白质组成分被选择性地升高在其他肿瘤中。作为概念的证明，针对来自这个谱系的一个例子蛋白质Tenascin-C（TNC），通过分离选择性和高亲和力的纳米抗体。已知TNC在许多肿瘤类型中丰富表达并在转移中发挥作用。TNC在患者的转移部位中丰富表达，并在来自数个原发性肿瘤类型的不同的转移部位中广泛表达。免疫PET / CT显示抗TNC纳米抗体以极高的特异性结合TNBC肿瘤和转移部位。我们建议，这样的针对肿瘤和转移的通用纳米抗体是传递治疗药物到肿瘤和转移ECM的有前途的癌症不可知工具。

Metastases are hard to detect and treat, and they cause most cancer-related deaths. The relative lack of therapies targeting metastases represents a major unmet clinical need. The extracellular matrix (ECM) forms a major component of the tumor microenvironment in both primary and metastatic tumors, and certain ECM proteins can be selectively and abundantly expressed in tumors. Nanobodies against ECM proteins that show selective abundance in metastases have the potential to be used as vehicles for delivery of imaging and therapeutic cargoes. Here, we describe a strategy to develop phage-display libraries of nanobodies against ECM proteins expressed in human metastases, using as immunogens entire ECM-enriched preparations from triple-negative breast cancer (TNBC) and colorectal carcinoma (CRC) metastases to different organs as immunogens. In parallel, LC-MS/MS-based proteomics were used to define a metastasis-associated ECM signature shared by metastases from TNBC and CRC, and this conserved set of ECM proteins was selectively elevated in other tumors. As proof of concept, selective and high-affinity nanobodies were isolated against an example protein from this signature, Tenascin-C (TNC), known to be abundant in many tumor types and to play a role in metastasis. TNC was abundantly expressed in patient metastases and widely expressed across diverse metastatic sites originating from several primary tumor types. Immuno-PET/CT showed that anti-TNC nanobodies bind TNBC tumors and metastases with excellent specificity. We propose that such generic nanobodies against tumors and metastases are promising cancer-agnostic tools for delivery of therapeutics to tumor and metastatic ECM.