Lung cancer remains the leading cause of cancer death. In 2008, 2 206 771 new cases and 1 796 144 deaths were reported worldwide [1]. At diagnosis, approximately one third of the patients have a potentially resectable tumour that is confined to the chest without clinical evidence of mediastinal lymphadenopathy (clinical stages I and II). Nevertheless, even after complete surgical resection, the overall survival in such patients with early-stage disease remains disappointing. The 5-year survival rate even for patients with stage IA or IB non-small cell lung cancer (NSCLC) is 73% and 56%, respectively [2]. Besides, the 5-year risks of local or regional recurrence after surgery alone for NSCLC for stages IA, IB, IIA, IIB and IIIA are also high (16%, 23%, 37%, 39% and 30%, respectively [3]). The 5-year survival of small cell lung cancer (SCLC) patients with early-stage resected disease (T1,2N0M0) is roughly similar, around 50% [4]. Relapse of the disease at distant sites, despite complete removal of all macroscopic lesions, is the main cause of treatment failure [5–8]. The presence of micro-metastatic disease at resection is the likely reason for such relapse. However, the mechanisms involved in micro-metastases propagation remains to be clarified.

肺癌仍然是癌症死亡的主要原因。2008 年，全球报告了 2 206 771 例新病例和 1 796 144 例死亡 [1]。在诊断时，大约三分之一的患者有潜在可切除的肿瘤，仅限于胸部，没有纵隔淋巴结病的临床证据（临床 I 期和 II 期）。然而，即使在完全手术切除后，这些早期疾病患者的总体生存率仍然令人失望。即使是 IA 或 IB 期非小细胞肺癌 (NSCLC) 患者的 5 年生存率也分别为 73% 和 56% [2]。此外，IA、IB、IIA、IIB 和 IIIA 期 NSCLC 单独手术后 5 年局部或区域复发的风险也很高（分别为 16%、23%、37%、39% 和 30% [3 ]）。早期切除疾病 (T1,2N0M0) 的小细胞肺癌 (SCLC) 患者的 5 年生存率大致相似，约为 50% [4]。尽管完全切除了所有肉眼可见的病变，但远处部位的疾病复发是治疗失败的主要原因 [5-8]。切除时存在微转移性疾病是这种复发的可能原因。然而，微转移传播所涉及的机制仍有待阐明。