A subset of bacterial species that holds genes encoding for β-glucuronidase and β-galactosidase, enzymes involved in the metabolism of conjugated estrogens, is called the “estrobolome.” There is an emerging interest embracing this concept, as it may exert a selective impact on a number of pathologies, including oral cancer. Although the estrobolome bacteria are typically part of the gut microbiota, recent experimental pieces of evidence have suggested a crosstalk among oral and gut microbiota. In fact, several oral bacterial species are well represented also in the gut microbiota, and these microbes can effectively induce the estrobolome activation. The main pathways used for activating the estrobolome are based on the induction of the expression patterns for 2 bacterial enzymes: β-glucuronidase and aromatase, both involved in the increase of estrogen released in the bloodstream and consequently in the salivary compartment. Mechanistically, high estrogen availability in saliva is responsible for an increase in oral cancer risk for different reasons: briefly, 1) estrogens directly exert biological and metabolic effects on oral mucosa cells; 2) they can modulate the pathological profile of some bacteria, somewhere associated with neoplastic processes (i.e., Fusobacterium spp., Parvimonas ssp.); and 3) some oral bacteria are able to convert estrogens into carcinogenic metabolites, such as 4-hydroxyestrone and 16α-hydroxyestrone (16α-OHE), and can also promote local and systemic inflammation. Nowadays, only a small number of scientific studies have taken into consideration the potential correlations among oral dysbiosis, alterations of the gut estrobolome, and some hormone-dependent cancers: this lack of attention on such a promising topic could be a bias affecting the full understanding of the pathogenesis of several estrogen-related oral pathologies. In our article, we have speculated on the activity of an oral–gut–estrobolome axis, capable of synergizing these 2 important microbiotas, shedding light on a pilot hypothesis requiring further research.

中文翻译：

---

口腔-肠道-Estrobolome轴可能对口腔癌产生选择性影响

拥有编码 β-葡萄糖醛酸酶和 β-半乳糖苷酶（参与结合雌激素代谢的酶）基因的细菌物种子集被称为“雌激素酶组”。人们对这一概念产生了新的兴趣，因为它可能对包括口腔癌在内的许多病理学产生选择性影响。尽管雌曲醇细菌通常是肠道微生物群的一部分，但最近的实验证据表明口腔和肠道微生物群之间存在串扰。事实上，肠道微生物群中也有多种口腔细菌，这些微生物可以有效诱导雌曲醇组激活。用于激活雌激素释放组的主要途径基于诱导两种细菌酶的表达模式：β-葡萄糖醛酸酶和芳香酶，这两种酶都参与增加血流中释放的雌激素，从而增加唾液室中释放的雌激素。从机制上讲，唾液中雌激素的高可用性导致口腔癌风险增加，原因有多种：简而言之，1）雌激素直接对口腔粘膜细胞产生生物和代谢作用； 2) 它们可以调节某些与肿瘤过程相关的细菌的病理特征（即梭杆菌属、细单胞菌属）； 3）一些口腔细菌能够将雌激素转化为致癌代谢物，例如4-羟基雌酮和16α-羟基雌酮（16α-OHE），并且还可以促进局部和全身炎症。如今，只有少数科学研究考虑到口腔菌群失调、肠道雌曲醇组改变和一些激素依赖性癌症之间的潜在相关性：对这样一个有前途的话题缺乏关注可能会成为影响充分理解的偏见。几种与雌激素相关的口腔疾病的发病机制。在我们的文章中，我们推测了口腔-肠道-雌曲醇轴的活性，该轴能够协同这两个重要的微生物群，为需要进一步研究的初步假设提供线索。