Ramos-Santillan Vicente, Oshi Masanori, Nelson Erek, Endo Itaru, Takabe Kazuaki
Department of Surgical Oncology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
These authors contributed equally to this work.
World J Oncol. 2024 Apr;15(2):257-267. doi: 10.14740/wjon1751. Epub 2024 Mar 21.
Hepatocellular carcinoma (HCC) with high Ki67 protein expression, the most commonly used cell proliferation marker, is associated with an aggressive biologic phenotype; however, conventional immunostaining is hampered by variability in institutional protocol, specific antibody probe, and by assessor subjectivity. To this end, we hypothesized that Ki67 gene () expression would identify highly proliferative HCC, and clarify its association with oncologic outcome, tumor progression, and immune cell population in the tumor microenvironment (TME). Furthermore, we sought to identify the cell-cycle gene expression profile that confers this aggressive phenotype.
A total of 473 HCC patients with clinicopathological data associated with transcriptome were selected for this study: 358 patients from The Cancer Genome Atlas (TCGA) as the testing cohort, and 115 from GSE76427 as the validation cohort. Each cohort was divided into a highly proliferative group (MKi67-high) and the low MKi67 group (MKi67-low) by the median of Ki67 gene () expression levels.
MKi67-high HCC patients had worse disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS) independent of histological grade in the TCGA cohort. MKi67 expression correlated with histological grade and tumor size. MKi67 expression increased throughout the HCC carcinomatous sequence from normal liver, cirrhotic liver, early HCC, and advanced HCC. MKi67-high HCC was associated with higher intratumor heterogeneity, homologous recombination deficiency, and altered fraction as well as intratumoral infiltration of T helper type 1 (Th1) and Th2 cells, but lower interferon-gamma response and M2 macrophage infiltration. Cell proliferation-related gene sets in the Hallmark collection (E2F targets, G2M checkpoint, Myc target v1 and mitotic spindle), MTORC1 signaling, DNA repair, PI3K MTOR signaling, and unfolded protein response were all enriched in the MKi67-high HCC (false discovery rate (FDR) < 0.25).
High gene expression identified highly proliferative HCC with aggressive biology involving classical pathways in cell cycle regulation and DNA repair, as well as poor overall oncologic outcomes. This suggests potential for personalized treatment strategies, but validation and refinement of these observations require further research to elucidate the underlying mechanisms and validate therapeutic targeting of these pathways in MKi67-high HCC tumors.
肝细胞癌（HCC）中高表达的Ki67蛋白是最常用的细胞增殖标志物，与侵袭性生物学表型相关；然而，传统免疫染色受到机构方案、特异性抗体探针的变异性以及评估者主观性的阻碍。为此，我们假设Ki67基因（）表达可识别高增殖性HCC，并阐明其与肿瘤学结局、肿瘤进展以及肿瘤微环境（TME）中免疫细胞群体的关联。此外，我们试图确定赋予这种侵袭性表型的细胞周期基因表达谱。
本研究共纳入473例具有与转录组相关的临床病理数据的HCC患者：358例来自癌症基因组图谱（TCGA）作为测试队列，115例来自GSE76427作为验证队列。每个队列根据Ki67基因（）表达水平的中位数分为高增殖组（MKi67高）和低MKi67组（MKi67低）。
在TCGA队列中，MKi67高的HCC患者的无病生存期（DFS）、疾病特异性生存期（DSS）和总生存期（OS）较差，与组织学分级无关。MKi67表达与组织学分级和肿瘤大小相关。从正常肝脏、肝硬化肝脏、早期HCC到晚期HCC，MKi67表达在整个HCC癌变序列中增加。MKi67高的HCC与更高的肿瘤内异质性、同源重组缺陷、改变的分数以及肿瘤内1型辅助性T细胞（Th1）和2型辅助性T细胞浸润相关，但干扰素-γ反应和M2巨噬细胞浸润较低。标志性集合中的细胞增殖相关基因集（E2F靶点、G2M检查点、Myc靶点v1和有丝分裂纺锤体）、MTORC1信号传导、DNA修复、PI3K MTOR信号传导和未折叠蛋白反应在MKi67高的HCC中均富集（错误发现率（FDR）<0.25）。
高基因表达识别出具有侵袭性生物学行为的高增殖性HCC，涉及细胞周期调控和DNA修复的经典途径，以及总体肿瘤学结局较差。这提示了个性化治疗策略的潜力，但这些观察结果的验证和完善需要进一步研究以阐明潜在机制，并验证在MKi67高的HCC肿瘤中这些途径的治疗靶向性。
