Plenty of metagenomic studies have suggested possible associations between microbiome composition and colorectal cancer (CRC). However, these techniques are not economic enough for routine use so far. Therefore, we explored the possibility to detect species associated with colorectal cancer by conventional culture from rectal swab. Fifty-two patients newly diagnosed for adenoma/CRC and 52 age-matched controls were recruited and sampled. Rectal swabs were inoculated on several types of plates and incubated appropriately under both aerobic and anaerobic conditions. All colonial morphotypes were subcultured and identified using MALDI-ToF MS. Although no bacterial species was significantly associated with CRC in our study, we surprisingly observed a strong and significant overrepresentation of the yeast Candida albicans in cases (P = 0.0066, odds ratio 5.444 [95% CI 1.449–20.462]). Potential confounding factors were associated neither with CRC (history of CRC in first-degree relatives, a personal history of appendectomy and cholecystectomy, increased BMI (body mass index), and the percentage of males) nor with C. albicans presence (preexisting diabetes and PPI medication) in our cohort. A growing body of evidence supports the view that C. albicans does cause cancer in humans. We hypothesize that presence of C. albicans in the gut may induce or facilitate some part of the sporadic CRC cases. Our observation should be a strong incentive to verify the potential usefulness of the easily culturable C. albicans yeast as a screening marker for patients at risk of CRC or those suffering an early asymptomatic stage of CRC.

大量的宏基因组学研究表明，微生物组组成与结直肠癌（CRC）之间可能存在关联。然而，到目前为止，这些技术对于常规使用而言还不够经济。因此，我们探讨了通过常规培养从直肠拭子中检测与大肠癌相关的物种的可能性。新招募了52例腺瘤/ CRC患者和52例年龄相匹配的对照者并进行了抽样。将直肠拭子接种在几种类型的平板上，并在有氧和厌氧条件下适当孵育。所有的结肠形态型都传代培养，并使用MALDI-ToF MS进行鉴定。尽管在我们的研究中，没有细菌与CRC显着相关，但我们惊讶地观察到了白色念珠菌的强烈而显着的过量表达。在某些情况下（P  = 0.0066，优势比为5.444 [95％CI 1.449-20.462]）。潜在的混杂因素既与CRC（一级亲属CRC的病史，阑尾切除术和胆囊切除术的个人病史，BMI（体重指数）增加以及男性的百分比）相关，也与白色念珠菌的存在（既往糖尿病和PPI药物）。越来越多的证据支持白念珠菌确实会引起人类癌症的观点。我们假设肠道中存在白色念珠菌可能诱发或促进部分散发性CRC病例。我们的观察结果应该是强烈的动力，以验证易于培养的白色念珠菌的潜在用途 酵母作为筛查标志物，可用于有CRC风险的患者或患有CRC的无症状早期阶段的患者。