每日英语一讲,助力四六级——科学家发现预防癌症的强大新方法

传统认知中，癌症源于正常细胞 DNA 突变后失控增殖，但近年研究颠覆这一观点 —— 科学家发现健康组织中也普遍存在 “致癌驱动突变”，比如约 1/4 的健康皮肤细胞、中年人群超半数食道表面细胞都携带这类突变。而这些 “准癌细胞” 未发展成肿瘤，关键在于周围健康细胞的有益突变能抑制其生长，这为癌症预防开辟新方向。

研究显示，健康细胞可通过竞争资源 “压制” 突变细胞。2024 年《自然・遗传学》发布的小鼠实验表明，糖尿病药物二甲双胍能让食道健康细胞产生代谢变化，抵消携带 PIK3CA 致癌突变细胞的优势；反之，高脂饮食会助突变细胞增殖，肥胖人群中这类细胞也更多。此外，慢性炎症被证实是 “准癌细胞” 恶变的推手，如空气污染引发肺部炎症后，会促使突变细胞形成肿瘤，针对免疫蛋白白细胞介素 - 1β 的药物可抑制这一过程。CRISPR 基因编辑等技术的进步，也加速了有害与有益突变的研究，为高风险人群（如 BRCA 基因突变者、前吸烟者）的癌症预防带来新希望。

Scientists are discovering a powerful new way to prevent cancer

科学家发现预防癌症的强大新方法

In the popular imagination, cancer starts with a mutation in the DNA of a normal cell. That mutation allows the cell to multiply uncontrollably, circumventing the body’s usual quality-control checks. Eventually, a tumour forms and breakaway cells from it spread to other parts of the body.

在大众印象中，癌症始于正常细胞DNA的突变。这种突变使细胞失控地增殖，绕过身体通常的质量控制检查。最终，肿瘤形成，部分脱落的细胞会扩散到身体的其他部位。

But in the past few years scientists have been finding something surprising—so-called cancer-driver mutations are also common in healthy tissue. Such mutations appear in around a quarter of healthy skin cells. When a person is middle aged more than half the surface of the oesophagus and nearly 10% of the lining of the stomach is covered by cells with cancer-driver mutations. These populations of cells have also been confirmed in many other tissues, including the colon, lungs and ovaries.

然而，过去几年科学家发现了令人惊讶的现象——所谓的“癌症驱动突变”在健康组织中也很常见。这类突变约出现在四分之一的健康皮肤细胞中。当人进入中年时，超过一半的食道表面以及近10%的胃黏膜都覆盖着带有癌症驱动突变的细胞。这些细胞群体在结肠、肺和卵巢等其他组织中也被确认存在。

Why these cells, which are primed to become cancerous, do not grow into tumours is a mystery that scientists are now starting to solve. It seems that cells with faulty DNA can be prevented from growing into full-blown cancers through the activity of healthy cells around them with beneficial mutations in their DNA. Encouraging those healthy cells to grow could become an effective strategy for stopping cancer. This new understanding of cancer comes from a better understanding of normal tissue growth. As cells divide, each daughter cell is born with a unique set of random genetic mutations. On the outermost layers of organs such as the oesophagus, skin and stomach, those best adapted to their environments push out the rest, which are then shed from the tissue.

为什么这些本有潜在癌变能力的细胞没有发展成肿瘤，是科学家们正在开始解答的谜题。研究显示，携带有益DNA突变的健康细胞能够抑制这些异常细胞发展为癌症。通过促进这些健康细胞的生长，或许可以成为阻止癌症的一种有效策略。这一新的癌症理解来源于对正常组织生长机制的深入理解：随着细胞分裂，每个子细胞都带有独特的随机基因突变。在食道、皮肤和胃等器官的最外层，最适应环境的细胞会排挤其他细胞，而被排挤的细胞会从组织脱落。

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