正文翻译

Bacteria and fungi can be found lurking in and around tumours. These microbial residents may be crucial to understanding how cancer develops and how to treat it.细菌和真菌潜伏在肿瘤内部和周围，这些微生物居民对于我们了解癌症的形成机制和治疗癌症可能至关重要。

Our bodies are thriving habitats for other life-forms. Our guts, mouths, noses and skin support diverse communities of microbes that can be both good and bad for our health. But in recent years scientists have been finding microbes in an altogether more surprising place – in tumours.我们人体是其他生物繁衍的栖息地。我们的内脏、嘴巴、鼻子、皮肤养活着各种微生物群落，它们对我们的健康既有利又有弊。但近年来，科学家们在一个完全出乎意料的部位——肿瘤中发现了微生物。

It is common to think of cancers as simply masses of a patient's own cells that malfunction and grow uncontrollably. They are in fact communities of many different cell types, which is part of the reason why cancers are so hard to treat – it is difficult to target them without harming healthy tissue too.人们通常认为，癌症只是患者自身的大量细胞出现故障和生长失控。其实癌症是由许多不同类型的细胞组成的群落，这也是癌症难以治疗的部分原因——很难在不损伤健康组织的情况下靶向消灭癌细胞。原创翻译：龙腾网 http://www.ltaaa.cn 转载请注明出处

But tumours also play host to a collection of cells from other life-forms entirely – bacteria and fungi. Some thrive in the environment around a tumour while others live inside the cancer cells themselves.但肿瘤也完全是其他生物细胞的宿主——细菌和真菌。一些在肿瘤周围的环境中茁壮成长，另一些则存在于癌细胞的内部。

Until recently, however, the role that these microbes play in tumours has not been clearly understood. Now scientists are starting to unravel whether these tumour-associated microorganisms are accomplices that assist cancer cells as they develop or just unfortunate bystanders caught up in the tumour. And the answers could provide new approaches to treating and preventing cancers.但直到最近，科学家一直没有搞清楚这些微生物在肿瘤中发挥的作用。现在科学家着手揭开这个谜团，与肿瘤相关的微生物是癌细胞生长的帮凶？还是只是不幸卷入肿瘤中的旁观者？答案也许能提供治疗和预防癌症的新方法。

Fusobacterium nucleatum is commonly associated with the mouth, but is also found in many tumours具核梭杆菌通常与口腔相关，但也存在于许多肿瘤中。

In a 2017 study Ravid Straussman, a cancer biologist at the Weizmann Institute of Science in Rehovot, Israel and his team showed that some bacteria living inside human pancreatic cancers can protect the tumours by inactivating a common chemotherapy drug. They found that one particular of bacteria, known as Gammaproteobacteria, could break down gemcitabine: a drug used to treat a number of cancers including those found in the bladder, breast and pancreas. This helped the tumours become resistant to the drug. When the team injected mice with colon cancer with the bacteria, the mice's cancers also became resistant to the drug. But when the researchers gave the mice an antibiotic alongside the chemotherapy drug, the resistance disappeared.拉韦德·施特劳斯曼是以色列雷霍沃特的魏茨曼科学研究所的癌症生物学家，他和团队在 2017 年的一项研究发现，人类胰腺癌内部的某些细菌能使一种常见的化疗药物失去活性，以此来保护肿瘤。他们发现一种特殊的γ‐变形菌纲可以分解吉西他滨：这是一种用于治疗多种癌症的药物，包括膀胱癌、乳腺癌、胰腺癌。这有助于肿瘤对药物产生耐药性。当研究团队给患有结肠癌的小鼠注射这种细菌时，小鼠的癌症也对该药物产生了耐药性。但当研究人员给小鼠联合注射抗生素和化疗药物时，耐药性消失了。

Further to these findings, research published in 2019 by a team at Tohoku University in Japan looked retrospectively at patients suffering from advanced cancers who were treated with either a chemotherapeutic drug alone and those who also received an antibiotic in addition to the chemotherapy in an attempt to prevent or treat an existing infection. They found that patients who were given an antibiotic had a better response to treatment. Although the study did not examine the amount of bacteria present in the cancer tissue of these patients, the researchers speculated that the antibiotics might have eliminated tumour-associated bacteria, which may have been interfering with the cancer treatment.除了这些发现之外，日本东北大学的一个团队于 2019 年发表的研究报告回顾了两类癌症晚期患者，一类仅接受化疗药物治疗，另一类为了预防或治疗现有感染，除了化疗还接受了抗生素治疗。他们发现接受抗生素治疗的患者有更好的疗效。尽管该研究没有检查患者的癌症组织内存在的细菌数量，但研究人员推测，抗生素可能消灭了与肿瘤相关的细菌，而这些细菌可能一直在干扰癌症治疗。

The studies offer a tantalising hint of what might be going on within tumours.这些研究为肿瘤内可能发生的情况提供了诱人的线索。

Straussman and his team are now hoping to build on these studies with a clinical trial involving patients with pancreatic cancer who failed their first line treatment. They will give patients an antibiotic known to act against Gammaproteobacteria, alongside a course of the chemotherapy drug gemcitabine, to see if the antibiotic improves their outcomes.施特劳斯曼和他的团队现在希望在这些研究的基础上，对一线治疗失败的胰腺癌患者进行临床试验。他们将给患者服用一种已知能够对抗γ‐变形菌的抗生素，同时服用一个疗程的化疗药物吉西他滨，以观察抗生素是否有助于改善他们的疗效。

But bacteria might also play other roles in cancer beyond protecting tumours from drug treatment.但细菌不仅保护肿瘤免受药物治疗，还可能在癌症中发挥着其他作用。

In 2020, Straussman's team looked at more than 1,500 human tumours across seven different cancer types: breast, lung, ovary, pancreas, melanoma, bone and brain. They found all of the tumour types were invaded by bacteria, which lived inside the cancer cells and some of the immune cells. Different tumour types had distinct communities of bacteria.2020 年，施特劳斯曼的团队研究了1500 多个人类肿瘤，涵盖7类癌症：乳腺癌、肺癌、卵巢癌、胰腺癌、黑色素瘤、骨癌、脑癌。他们发现所有类型的肿瘤都被细菌入侵了，它们存在于癌细胞和某些免疫细胞内。不同类型的肿瘤具有不同的细菌群落。

"Each of these bacteria have adapted to the unique tumour microenvironment in which they live," says Straussman. "In lung cancer, we demonstrated how people who smoke have more bacteria which can degrade nicotine – which is a smoke-related metabolite. In bone cancers, we see bacteria which metabolise hydroxyproline, which is a metabolite enriched in bone tumours."“其中的每一种细菌都适应了它们所在的独特的肿瘤微环境”，施特劳斯曼说道。“在肺癌中，我们发现吸烟者拥有较多可以降解尼古丁的细菌，尼古丁是一种与吸烟相关的代谢物。在骨癌中，我们发现了代谢羟脯氨酸的细菌，羟脯氨酸是骨肿瘤中富含的代谢物”。

In many cases it is still unclear whether the bacteria are helping the sufferer by keeping the cancer cells under control.在许多情况下，科学家仍不清楚细菌是否通过抑制癌细胞来帮助患者。

Bacteria found in some types of breast cancer, for example, can detoxify arsenate, a type of carcinogen known to increase the risk of breast cancer. Others can produce a chemical called mycothiol, which helps to reduce levels of harmful reactive oxygen molecules that can damage DNA.例如，在某些类型的乳腺癌中发现的细菌可以清除砷酸盐，它是一种已知会增加乳腺癌风险的致癌物质。还有些细菌可以产生一种叫做真菌硫醇的化学物质，它有助于降低有害的活性氧分子的水平，而活性氧分子会破坏DNA。

There is growing evidence, however, that in some cases, the tumour-dwelling bacteria may actually be making cancers worse.然而越来越多的证据表明，在某些情况下，肿瘤内的细菌可能会使癌症恶化。