癌细胞的转移受到其内在特征和肿瘤微环境（TME）的影响。然而，乳腺癌结前转移的分子机制仍不清楚。我们整合了 6 个单细胞数据集中 54 个样本的总共 216,963 个细胞，以描绘原发肿瘤和结前转移之间的细胞景观差异。我们揭示了三个不同的转移性上皮细胞亚型（Epi1、Epi2 和 Epi3）表现出不同的转移机制。具体来说，Epi1亚型的标记基因KCNK15在细胞分化轨迹上表现出基因表达增加，并受到转录因子ASCL1的特异性调控。在 Epi3 亚型中，我们强调 NR2F1 作为针对标记基因 MUCL1 的调节因子。此外，我们发现 Epi2 和 Epi3 亚型共享一些调节子，例如 ZEB1 和 NR2C1。同样，我们鉴定了 TME 中基质细胞和免疫细胞的特定亚型，并发现血管癌相关成纤维细胞可能通过结前转移中的 CXCL9 巨噬细胞促进毛细血管形成。转移性上皮细胞的所有三种亚型均与不良预后相关。总之，本研究剖析了乳腺癌结前转移中 TME 的瘤内异质性和重塑，为乳腺癌转移的机制提供了新的见解。© 2024。作者。

The metastasis of cancer cells is influenced by both their intrinsic characteristics and the tumor microenvironment (TME). However, the molecular mechanisms underlying pre-nodal metastases of breast cancer remain unclear.We integrated a total of 216,963 cells from 54 samples across 6 single-cell datasets to profile the cellular landscape differences between primary tumors and pre-nodal metastases.We revealed three distinct metastatic epithelial cell subtypes (Epi1, Epi2 and Epi3), which exhibited different metastatic mechanisms. Specifically, the marker gene KCNK15 of the Epi1 subtype exhibited increased gene expression along the cell differentiation trajectory and was specifically regulated by the transcription factor ASCL1. In the Epi3 subtype, we highlighted NR2F1 as a regulator targeting the marker gene MUCL1. Additionally, we found that the Epi2 and Epi3 subtypes shared some regulons, such as ZEB1 and NR2C1. Similarly, we identified specific subtypes of stromal and immune cells in the TME, and discovered that vascular cancer-associated fibroblasts might promote capillary formation through CXCL9+ macrophages in pre-nodal metastases. All three subtypes of metastatic epithelial cells were associated with poor prognosis.In summary, this study dissects the intratumoral heterogeneity and remodeling of the TME in pre-nodal metastases of breast cancer, providing novel insights into the mechanisms underlying breast cancer metastasis.© 2024. The Author(s).