Table 1_Microbiota disparities in stool, oral swabs, and saliva between control and early-onset colorectal neoplasia groups: an exploratory analysis.docx

Background/aimThe increasing incidence of early-age-onset colorectal neoplasia (EAO-CRN) in individuals under 50 years old poses a global health concern. This study aimed to investigate the variations in the microbiota in individuals with EAO-CRN compared with a control group, utilizing stool, oral swab, and saliva samples.
MethodsParticipants under 50 years of age provided stool, oral swab, and saliva samples. Colorectal neoplasia was classified into the serrated lesions and adenoma–carcinoma groups based on histology and compared with a control group without polyps. The alpha diversity and the taxonomic abundance differences were assessed using amplicon sequence variants obtained through 16S rRNA sequencing and matched taxonomy data.
ResultsA total of 45 participants were included: 14 in the control, 13 in the serrated lesions, and 18 in the adenoma–carcinoma groups. Microbial analysis revealed no significant differences in the alpha diversity among the groups. However, the stool samples from the serrated lesions group had higher levels of the families Erysipelotrichaceae and Lachnospiraceae compared with the control group. Analysis of the oral swabs indicated relatively elevated levels of the family Streptococcaceae in both the serrated lesions and adenoma–carcinoma groups. In the saliva samples, the serrated lesions and adenoma–carcinoma groups showed higher levels of the family Lactobacillaceae, with the serrated lesions group also exhibiting elevated levels of the family Bifidobacteriaceae.
ConclusionsThis study elucidates the microbiota changes associated with EAO-CRN, distinguishing between serrated lesions and adenoma–carcinoma groups using stool, oral swab, and saliva samples. These findings contribute to the understanding of the relationship between microbiota and colorectal neoplasia in the early-onset population.

背景与研究目的：
早发性结直肠肿瘤（early-age-onset colorectal neoplasia, EAO-CRN）在50岁以下人群中的发病率持续攀升，已成为一项全球性公共卫生关切。本研究旨在通过采集粪便、口腔拭子及唾液样本，探究早发性结直肠肿瘤患者与对照组人群的菌群差异。

方法：
本研究纳入50岁以下的受试者，采集其粪便、口腔拭子及唾液样本。根据组织病理学特征，将结直肠肿瘤患者分为锯齿状病变组与腺瘤-癌组，并与无息肉的对照组进行比较。通过16S rRNA测序获得的扩增子序列变体（amplicon sequence variants, ASV）及匹配的分类学数据，评估各组的α多样性及分类学丰度差异。

结果：
本研究共纳入45名受试者，其中对照组14例、锯齿状病变组13例、腺瘤-癌组18例。菌群分析结果显示，各组间α多样性无显著差异。然而，与对照组相比，锯齿状病变组的粪便样本中丹毒丝菌科（Erysipelotrichaceae）与毛螺菌科（Lachnospiraceae）的相对丰度更高。口腔拭子分析结果显示，锯齿状病变组与腺瘤-癌组的链球菌科相对丰度均有所升高。在唾液样本中，锯齿状病变组与腺瘤-癌组的乳杆菌科（Lactobacillaceae）相对丰度更高，且锯齿状病变组的双歧杆菌科（Bifidobacteriaceae）相对丰度也有所升高。

结论：
本研究通过粪便、口腔拭子及唾液样本，明确了早发性结直肠肿瘤相关的菌群变化，并区分了锯齿状病变组与腺瘤-癌组的菌群特征。本研究结果有助于进一步理解早发人群中菌群与结直肠肿瘤之间的关联。