柳叶刀子刊发表廖宁团队乳腺癌淋巴结转移基因组学与免疫特征研究成果
来自前哨淋巴结的单一淋巴结转移与多发淋巴结转移相比，乳腺癌患者的生存时间显著较长。不过，关于乳腺癌从前哨淋巴结下游转移至多个引流区域淋巴结的基因组学和免疫特征信息极少。
2021年8月25日，英国《柳叶刀》旗下《生物医学》在线发表广东省人民医院陈博、张国淳、赖建国、肖伟锴、李学瑞、李焯辉、莫小霈、李凯、王钰雷、曹莉、贾茗涵、任重阳、温灵珠、廖宁等学者的研究报告，对乳腺癌前哨淋巴结单一转移和多发转移与其对应原发肿瘤的520个基因及其免疫特征进行了比较。
该单中心回顾研究对2017年1月1日～2018年11月30日广东省人民医院157例女性乳腺癌患者原发肿瘤和转移淋巴结的520个癌症相关基因进行大规模并行测序和基因组分析，并对前哨淋巴结转移组20例患者和多发区域淋巴结组28例患者的原发肿瘤、转移淋巴结和相邻临床正常淋巴结进行全转录组分析。
结果发现，与前哨淋巴结单一转移相比，下游多发转移淋巴结（P=0.029）和乳腺原发肿瘤（P=0.011）的PIK3CA基因突变率显著较高。
与乳腺原发肿瘤相比，单一前哨淋巴结转移的14个基因突变率显著较高，多发淋巴结转移的15个基因突变率显著较高，其中仅4个基因（PIK3CA、CDK4、NFKBIA、CDKN1B）重叠。
与对应原发乳腺癌相比：
单一淋巴结转移：肿瘤突变负荷显著较低（P=0.0021）
多发淋巴结转移：肿瘤突变负荷稍低（P=0.083）。
根据基因集富集分析，多发区域淋巴结组的原发肿瘤和淋巴结转移都有4个特征上调，包括3个上皮→间质转化特征和1个血管生成特征。与多发区域淋巴结转移的标本相比，单一前哨淋巴结转移相邻正常淋巴结的杀伤型T淋巴细胞/调节型T淋巴细胞比值（P=0.045）和杀伤型T淋巴细胞/上皮→间质转化比例（P=0.023）都显著更高，表明多发区域淋巴结转移患者的免疫防御微环境可能较差，从而引起多发淋巴结转移。
因此，该单中心回顾研究结果表明，单一淋巴结转移与多发淋巴结转移相比，分子特征和免疫特征显著不同。多发淋巴结转移患者与单一淋巴结转移患者相比，肿瘤侵袭性特征较强、免疫特征较差。这些结果为淋巴结转移数量不同的乳腺癌患者个体化免疫治疗奠定了基础，故有必要进一步开展多中心大样本前瞻研究进行验证。
EBioMedicine. 2021 Aug 25;71:103542.
Genetic and immune characteristics of sentinel lymph node metastases and multiple lymph node metastases compared to their matched primary breast tumours.
Chen B, Zhang G, Lai J, Xiao W, Li X, Li C, Mok H, Li K, Wang Y, Cao L, Jia M, Ren C, Wen L, Wei G, Lin J, Li Y, Zhang Y, Chen X, Wu X, Zhang H, Li M, Liu J, Balch CM, Liao N.
Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China; School of Medicine, South China University of Technology, Guangzhou, Guangdong, China; The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China; Foshan Maternity and Children's Healthcare Hospital Affiliated to Southern Medical University, Foshan, Guangdong, China; Genecast Biotechnology Co., Ltd., Beijing, China; Beijing Ditan Hospital, Capital Medical University, Beijing, China; Burning Rock Biotech, Guangzhou, Guangdong, China; The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
BACKGROUND: Patients with breast cancer presenting with single lymph node metastasis (from a sentinel node) experience prolonged survival compared to patients with multiple lymph node metastases (≥3). However, little information is available on the genetic and immunological characteristics of breast cancer metastases within the regional lymph nodes as they progress from the sentinel lymph node (SLN) downstream to multiple regional lymph nodes (MLNs).
METHODS: Genomic profiling was performed using a next-generation sequencing panel covering 520 cancer-related genes in the primary tumour and metastatic lymph nodes of 157 female patients with breast cancer. We included primary tumours, metastatic lymph nodes and adjacent clinically normal lymph nodes (20 patients from the SLN group and 28 patients from the MLNs group) in the whole transcriptome analysis.
FINDINGS: The downstream metastatic lymph nodes (P = 0.029) and the primary breast tumours (P = 0.011) had a higher frequency of PIK3CA mutations compared to the SLN metastasis. We identified a distinct group of 14 mutations from single sentinel node metastasis and a different group of 15 mutations from multiple nodal metastases. Only 4 distinct mutations (PIK3CA, CDK4, NFKBIA and CDKN1B) were conserved in metastases from both lymph node settings. The tumour mutational burden (TMB) was significantly lower in single nodal metastasis compared to the paired primary breast cancer (P = 0.0021), while the decline in TMB did not reach statistical significance in the MLNs group (P = 0.083). In the gene set enrichment analysis, we identified 4 upregulated signatures in both primary tumour and nodal metastases from the MLNs group, including 3 Epithelial-mesenchymal transition(EMT) signatures and 1 angiogenesis signature. Both the CD8/Treg ratio and the CD8/EMT ratio were significantly higher in adjacent normal lymph nodes from patients with a single metastasis in the SLN compared with samples from the MLNs group (P = 0.045 and P = 0.023, respectively). This suggests that the immune defence from the MLNs patients might have a less favourable microenvironment, thus permitting multiple lymph nodes metastasis.
INTERPRETATION: Single lymph node metastases and multiple lymph node metastases have significant differences in their molecular profiles and immune profiles. The findings are associated with more aggressive tumour characteristics and less favourable immune charactoristics in patients with multiple nodal metastases compared to those with a single metastasis in the sentinel node.
FUNDING: This work was supported by funds from High-level Hospital Construction Project (DFJH201921), the National Natural Science Foundation of China (81902828 and 82002928), the Fundamental Research Funds for the Central Universities (y2syD2192230), and the Medical Scientific Research Foundation of Guangdong Province (B2019039).
KEYWORDS: Breast cancer; Sentinel lymph node metastases; Multiple lymph node metastases; Genome; Immune characteristics
PMID: 34454403
DOI: 10.1016/j.ebiom.2021.103542