“癌前期”一词通常是指肿瘤发展的早期阶段，由于分子和表型的改变，该阶段与正常组织有区别，导致异常细胞至少部分地自我维持并在限制细胞增殖的正常细胞信号之外发挥作用和生存。尽管这些细胞在组织学上通常与相同组织来源的相应正常和侵袭性癌细胞不同，但定义癌前期仍然是研究和临床界的一个挑战。一旦癌前病变发生足够的分子和表型变化，组织病理学家就会将该组织鉴定为“癌症”。尽管诊断癌症有时也具有挑战性，但侵袭性癌症的确定通常不太明确，并且表明转移性疾病的可能性和潜力很高。 “癌症特征”阐明了恶性转化的基本组织原则，但究竟有多少这些特征以及它们以何种结构定义癌前病变，尚未明确且一致地确定。在本专家建议中，我们为定义癌前病变的概念框架提供了一个起点，该框架基于分子、病理、临床和流行病学标准，目的是增进我们对癌前病变发生的初始变化和干预机会的理解。最早的时间点。© 2024。这是美国政府作品，在美国不受版权保护；可能适用外国版权保护。

The term 'precancer' typically refers to an early stage of neoplastic development that is distinguishable from normal tissue owing to molecular and phenotypic alterations, resulting in abnormal cells that are at least partially self-sustaining and function outside of normal cellular cues that constrain cell proliferation and survival. Although such cells are often histologically distinct from both the corresponding normal and invasive cancer cells of the same tissue origin, defining precancer remains a challenge for both the research and clinical communities. Once sufficient molecular and phenotypic changes have occurred in the precancer, the tissue is identified as a 'cancer' by a histopathologist. While even diagnosing cancer can at times be challenging, the determination of invasive cancer is generally less ambiguous and suggests a high likelihood of and potential for metastatic disease. The 'hallmarks of cancer' set out the fundamental organizing principles of malignant transformation but exactly how many of these hallmarks and in what configuration they define precancer has not been clearly and consistently determined. In this Expert Recommendation, we provide a starting point for a conceptual framework for defining precancer, which is based on molecular, pathological, clinical and epidemiological criteria, with the goal of advancing our understanding of the initial changes that occur and opportunities to intervene at the earliest possible time point.© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.