Ohni Sumie, Yamaguchi Hiromi, Hirotani Yukari, Nakanishi Yoko, Midorikawa Yutaka, Sugitani Masahiko, Naruse Hiromu, Nakayama Tomohiro, Makishima Makoto, Esumi Mariko
Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo 173-8610, Japan.
Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo 173-8610, Japan.
Oncol Lett. 2022 Jan;23(1):22. doi: 10.3892/ol.2021.13140. Epub 2021 Nov 17.
Frequent recurrence is a major issue in liver cancer and histological heterogeneity frequently occurs in this cancer type. However, it has remained elusive whether such cancers are multicentric or monoclonal. To elucidate the clonal evolution of hepatocellular carcinoma (HCC) recurrence and combined hepatocellular-cholangiocarcinoma (cHCC-CCA) development, the somatic mutation frequency and signatures in a patient with triple occurrence of liver cancer every three years were examined, with samples designated as #1HCC, #2HCC and #3cHCC-CCA, respectively. A total of four tumor regions, including HCC (#3HCC) and intrahepatic CCA (#3iCCA) components of #3cHCC-CCA, and three nontumor regions (#1N, #2N and #3N) were precisely dissected from formalin-fixed paraffin-embedded tissues of each surgical specimen. DNA was extracted and subjected to tumor-specific somatic mutation determination. Of note, five nonsynonymous single-nucleotide variants (SNVs), namely those of KMT2D, TP53, DNMT3A, PKHD1 and TLR4, were identified in #3cHCC-CCA. All five SNVs were detected in both #3HCC and #3iCCA and #2HCC but not in #1HCC. The telomerase reverse transcriptase (TERT) promoter mutation C228T, but not C250T, was observed in all tumors. Digital PCR of C228T also indicated the presence of the TERT promoter mutation C228T in nontumorous liver tissues (#1N, #2N and #3N) at a frequency of 0.11-0.83% compared with normal liver and blood samples. These results suggest the following phylogenetic evolution of three metachronous liver cancers: #1HCC was not related to #2HCC, #3HCC and #3iCCA; both #3HCC and #3iCCA arose from #2HCC. From the above, three novel findings were deduced: i) Both multicentric occurrence and intrahepatic metastasis may be involved in liver cancer in a three-year interval; ii) transdifferentiation from HCC to iCCA is a possible pathogenic mechanism of cHCC-CCA; and iii) a nontumorous, noncirrhotic liver may contain a preneoplastic region with a cancer driver mutation in the TERT promoter.
频繁复发是肝癌的一个主要问题，并且组织学异质性在这种癌症类型中经常出现。然而，这种癌症是多中心性的还是单克隆性的，仍然不清楚。为了阐明肝细胞癌（HCC）复发和肝内胆管癌合并肝细胞癌（cHCC-CCA）发生的克隆进化，对一名每三年发生三次肝癌的患者的体细胞突变频率和特征进行了检查，样本分别标记为#1HCC、#2HCC和#3cHCC-CCA。从每个手术标本的福尔马林固定石蜡包埋组织中精确解剖出总共四个肿瘤区域，包括#3cHCC-CCA的HCC（#3HCC）和肝内胆管癌（#3iCCA）成分，以及三个非肿瘤区域（#1N、#2N和#3N）。提取DNA并进行肿瘤特异性体细胞突变测定。值得注意的是，在#3cHCC-CCA中鉴定出五个非同义单核苷酸变异（SNV），即KMT2D、TP53、DNMT3A、PKHD1和TLR4的变异。在#3HCC、#3iCCA和#2HCC中均检测到所有五个SNV，但在#1HCC中未检测到。在所有肿瘤中均观察到端粒酶逆转录酶（TERT）启动子突变C228T，而非C250T。C228T的数字PCR还表明，与正常肝脏和血液样本相比，非肿瘤性肝组织（#1N、#2N和#3N）中TERT启动子突变C228T的频率为0.11 - 0.83%。这些结果提示了以下三种异时性肝癌的系统发育进化：#1HCC与#2HCC、#3HCC和#3iCCA无关；#3HCC和#3iCCA均起源于#2HCC。基于上述内容，得出了三个新发现：i）在三年的时间间隔内，多中心发生和肝内转移可能都参与了肝癌的发生；ii）从HCC向iCCA的转分化是cHCC-CCA的一种可能致病机制；iii）非肿瘤性、非肝硬化的肝脏可能含有一个在TERT启动子中具有癌症驱动突变的癌前区域。
