Yan Shushan, Liu Tie, Zhao Haobin, Zhao Chunbo, Zhu Yuxin, Dai Wenqing, Sun Wenchang, Wang Honggang, Sun Junxi, Zhao Lu, Xu Donghua
Department of Gastrointestinal and Anal Diseases Surgery, Affiliated Hospital of Shandong Second Medical University, Weifang, China.
Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States.
Front Microbiol. 2024 Aug 21;15:1422536. doi: 10.3389/fmicb.2024.1422536. eCollection 2024.
Accumulating evidence has supported that gut microbiota and metabolite profiles play indispensable roles in the pathogenesis of colorectal cancer (CRC), which ranks as the third most common cancer and the second leading cause of cancer-related deaths worldwide. However, alterations in tumoral or circulating microbiomes in CRC remain incompletely understood. It has been well-documented that tissue or serum microbiomes with low microbial biomass could be screened by use of 2bRAD sequencing for microbiome (2bRAD-M) at the species resolution.
In order to validate the microbial biomarkers distinguishing CRC and the variations in microorganisms present in serum and tumors, we performed 2bRAD-M to characterize the microbiomes in serum and cancer tissues of CRC patients with and without lymph node or liver metastasis.
The composition of dominated microbiota in serum was different from that of tissue samples, while the microbial community composition of tumors was similar to that of the tumor-adjacent tissues. The analysis of α-diversity and β-diversity has revealed notable variations in serum microbiota diversities in CRC patients, particularly those with liver metastasis. Multiple CRC-specific microbial species, such as Moraxella A cinereus, Flavobacterium sp001800905, and , were identified in serum. Complicated functions and KEGG pathways were also confirmed in CRC according to the metastasis status.
This study has found significant alterations in the microbial compositions and diversities in CRC and CRC-specific microbial species in both circulation and cancer tissues, which may serve as promising biomarkers for the screening, diagnosis and prognosis prediction of CRC. In particular, CRC-specific bacterial taxa are promising markers, holding transformative potentials in establishing personalized screening and risk stratification, refining much earlier non-invasive diagnostic approaches, and enhancing diagnostic sensitivity.
越来越多的证据支持肠道微生物群和代谢物谱在结直肠癌（CRC）的发病机制中发挥着不可或缺的作用，结直肠癌是全球第三大常见癌症和癌症相关死亡的第二大主要原因。然而，CRC中肿瘤或循环微生物群的改变仍未完全了解。已有充分文献证明，可通过使用用于微生物组的2bRAD测序（2bRAD-M）在物种分辨率下筛选微生物生物量低的组织或血清微生物组。
为了验证区分CRC的微生物生物标志物以及血清和肿瘤中存在的微生物的变化，我们进行了2bRAD-M以表征有无淋巴结或肝转移的CRC患者血清和癌组织中的微生物组。
血清中占主导地位的微生物群组成与组织样本不同，而肿瘤的微生物群落组成与肿瘤邻近组织相似。α多样性和β多样性分析揭示了CRC患者血清微生物群多样性的显著变化，特别是那些有肝转移的患者。在血清中鉴定出多种CRC特异性微生物物种，如灰莫拉菌、黄杆菌sp001800905等。根据转移状态，还在CRC中证实了复杂的功能和KEGG途径。
本研究发现CRC以及循环和癌组织中CRC特异性微生物物种的微生物组成和多样性有显著改变，这可能作为CRC筛查、诊断和预后预测的有前景的生物标志物。特别是，CRC特异性细菌分类群是有前景的标志物，在建立个性化筛查和风险分层、完善更早的非侵入性诊断方法以及提高诊断敏感性方面具有变革潜力。
