The dysregulation of gut microbiota is pivotal in colorectal carcinogenesis. Meanwhile, altered gut microbiome may affect the development of intestinal diseases through interaction with the host genes. However, the synergy between the altered gut microbiota composition and differential expression of specific genes in colorectal cancer (CRC) remains elusive. Thus, we integrated the data from 16S rRNA gene sequences and RNA sequences to investigate the potential relationship between genes and gut microbes in patients with CRC. Compared with normal samples, the presence of Proteobacteria and Fusobacteria increased considerably in CRC samples; conversely, the abundance of Firmicutes and Spirochaetes decreased markedly. In particular, the genera Fusobacterium, Catenibacterium, and Shewanella were only detected in tumor samples. Meanwhile, a closely interaction between Butyricimonas and Clostridium was observed in the microbiome network. Furthermore, a total of 246 (differentially expressed genes) DEGs were identified between tumor and normal tissues. Both DEGs and microbiota were involved in bile secretion and steroid hormone biosynthesis pathways. Finally, genes like cytochrome P450 family 3 subfamily A member 4 (CYP3A4) and ATP binding cassette subfamily G member 2 (ABCG2) enriched in these two pathways were connected with the prognosis of CRC, and CRC patients with low expression level of CYP3A4 and ABCG2 had longer survival time. Identifying the complicated interaction between gut microbiota and the DEGs contributed to further understand the pathogenesis of CRC, and these findings might enable better diagnosis and treatment of CRC patients.

中文翻译：

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结直肠癌微生物群组成及基因表达的综合分析

肠道菌群失调是结直肠癌发生的关键。同时，肠道微生物组的改变可能通过与宿主基因的相互作用影响肠道疾病的发展。然而，改变的肠道微生物群组成与结直肠癌（CRC）中特定基因的差异表达之间的协同作用仍然难以捉摸。因此，我们整合了来自 16S rRNA 基因序列和 RNA 序列的数据，以研究基因与 CRC 患者肠道微生物之间的潜在关系。与正常样本相比，CRC样本中变形杆菌和梭杆菌的存在显着增加；相反，厚壁菌门和螺旋藻门的丰度显着下降。特别是梭杆菌属、链状杆菌属和希瓦氏菌属仅在肿瘤样本中检测到。同时，在微生物组网络中观察到 Butyricimonas 和梭菌之间的密切相互作用。此外，在肿瘤和正常组织之间共鉴定出 246 个（差异表达基因）DEG。DEG 和微生物群都参与了胆汁分泌和类固醇激素生物合成途径。最后，在这两条途径中富集的细胞色素P450家族3亚家族A成员4（CYP3A4）和ATP结合盒亚家族G成员2（ABCG2）等基因与CRC的预后有关，CYP3A4和ABCG2低表达的CRC患者有更长的生存时间。确定肠道微生物群与 DEG 之间复杂的相互作用有助于进一步了解 CRC 的发病机制，这些发现可能有助于更好地诊断和治疗 CRC 患者。