Cancer is one of the leading causes of premature death and constitutes a challenge for both low- and high-income societies. Previous evidence supports a close association between modifiable risk factors, including dietary habits, and cancer risk. Investigation of molecular mechanisms that mediate the pro-oncogenic and anti-oncogenic effects of diet is therefore fundamental. MicroRNAs (miRNAs) have received much attention in the past few decades as crucial molecular elements of human physiology and disease. Aberrant expression patterns of these small noncoding transcripts have been observed in a wide array of cancers. Interestingly, human miRNAs not only can be modulated by bioactive dietary components, but it has also been proposed that diet-derived miRNAs may contribute to the pool of human miRNAs. Results from independent groups have suggested that these exogenous miRNAs may be functional in organisms. These findings open the door to novel and innovative approaches to cancer therapy. Here, we provide an overview of the biology of miRNAs, with a special focus on plant-derived dietary miRNAs, summarize recent findings in the field of cancer, address the possible applications to clinical practice and discuss obstacles and challenges in the field.

癌症是导致过早死亡的主要原因之一，对低收入和高收入社会都构成挑战。先前的证据支持可改变的风险因素（包括饮食习惯）与癌症风险之间的密切关联。因此，研究介导饮食的促癌和抗癌作用的分子机制至关重要。在过去的几十年中，作为人类生理和疾病的关键分子元素，MicroRNAs (miRNAs) 受到了广泛关注。已在多种癌症中观察到这些小的非编码转录物的异常表达模式。有趣的是，人类 miRNA 不仅可以通过具有生物活性的膳食成分进行调节，而且也有人提出饮食衍生的 miRNA 可能有助于人类 miRNA 的库。来自独立小组的结果表明，这些外源 miRNAs 可能在生物体中发挥作用。这些发现为癌症治疗的新颖和创新方法打开了大门。在这里，我们概述了 miRNA 的生物学，特别关注植物来源的膳食 miRNA，总结了癌症领域的最新发现，讨论了临床实践中可能的应用，并讨论了该领域的障碍和挑战。