肾母细胞瘤（WT）患者总体上具有良好的生存率，但患有弥漫性退变（DA）的WT亚组患者由于经常对化疗产生耐药性，预后较差。我们假设 DA WT 细胞可能会发生变化，例如获得对 DNA 损伤和拷贝数畸变 (CNA) 的持续耐受性，这最终可能导致它们对化疗产生耐药性。在组织微阵列系统中将化疗治疗的 DA WT (n=12) 的组织切片与化疗治疗的非间变性 WT (n=15) 进行比较，从而能够分析 769 个肿瘤区域。对所有区域的间变特征进行评分，并使用免疫组织化学来量化 p53 表达、增殖指数 (Ki67) 和 DNA 双链断裂 (γH2AX)。通过基于芯片的基因分型和靶向测序对 TP53 突变进行评估。增殖指数和 DNA 双链断裂频率（γH2AX 点表达）随着退变评分的升高而增加。几乎所有 (95.6%) 发生全面退行性变的区域都存在 TP53 突变或杂合性缺失 (LOH)，同时 CNA 数量增加。有趣的是，具有 LOH 的野生型 TP53 和仅一种退变特征（退变得分 1）的区域也比没有任何退变特征的区域（得分 0）具有显着更高的增殖指数、更多的 DNA 双链断裂和更多的 CNA；这些区域可能是在 TP53 突变的选择性压力下的前变性细胞群。总之，我们认为 DA WT 的化疗耐药性可能部分是由于间变细胞的高增殖能力造成的，这些细胞也具有高双链 DNA 断裂和 CNA 的负担，并且 WT 中逐渐出现了间变性。版权所有 © 2023 年。由爱思唯尔公司出版。

Patients with Wilms tumor (WT) in general have excellent survival, but the prognosis of patients belonging to the subgroup of WT with diffuse anaplasia (DA) is poor due to frequent resistance to chemotherapy. We hypothesized that DA WT cells might undergo changes, such as acquiring a persistent tolerance to DNA damage and copy number aberrations (CNAs), that could eventually lead to their resistance to chemotherapy treatment. Tissue sections from chemotherapy-treated DA WTs (n=12) were compared to chemotherapy-treated non-anaplastic WTs (n=15) in a tissue microarray system, enabling analysis of 769 tumour regions. All regions were scored for anaplastic features and immunohistochemistry was used to quantify p53 expression, proliferation index (Ki67) and DNA double strand breaks (γH2AX). CNAs were assessed by array-based genotyping and TP53 mutation by targeted sequencing. Proliferation index and the frequency of DNA double strand breaks (γH2AX dot expression) increased with higher anaplasia scores. Almost all (95.6%) areas with full-scale anaplasia had TP53 mutation or loss of heterozygosity (LOH) along with an increased amount of CNAs. Interestingly, areas with wild-type TP53 with LOH and only one feature of anaplasia (anaplasia score 1) also had significantly higher proliferation indices, more DNA double strand breaks, and more CNAs than regions without any anaplastic features (score 0); such areas may be pre-anaplastic cell populations under selective pressure for TP53 mutations. In conclusion, we suggest that chemoresistance of DA WT may be partly explained by a high proliferative capability of anaplastic cells that also have a high burden of double stranded DNA breaks and CNAs, and that there is a gradual emergence of anaplasia in WT.Copyright © 2023. Published by Elsevier Inc.