Brunsell Tuva Høst, Sveen Anita, Bjørnbeth Bjørn Atle, Røsok Bård I, Danielsen Stine Aske, Brudvik Kristoffer Watten, Berg Kaja C G, Johannessen Bjarne, Cengija Vanja, Abildgaard Andreas, Guren Marianne Grønlie, Nesbakken Arild, Lothe Ragnhild A
Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway; K. G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway; Institute for Clinical Medicine, University of Oslo, Oslo, Norway.
K. G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Norwegian Radium Hospital, Oslo, Norway; Department of Gastrointestinal Surgery, Oslo University Hospital, Oslo, Norway.
Clin Colorectal Cancer. 2020 Mar;19(1):e26-e47. doi: 10.1016/j.clcc.2019.09.003. Epub 2019 Dec 12.
The prevalence and clinical implications of genetic heterogeneity in patients with multiple colorectal liver metastases remain largely unknown. In a prospective series of patients undergoing resection of colorectal liver metastases, the aim was to investigate the inter-metastatic and primary-to-metastatic heterogeneity of mutations in KRAS, NRAS, BRAF, and PIK3CA and their prognostic impact.
We analyzed the mutation status among 372 liver metastases and 78 primary tumors from 106 patients by methods used in clinical routine testing, by Sanger sequencing, by next-generation sequencing (NGS), and/or by droplet digital polymerase chain reaction. The 3-year cancer-specific survival (CSS) was analyzed using the Kaplan-Meier method.
Although Sanger sequencing indicated inter-metastatic mutation heterogeneity in 14 of 97 patients (14%), almost all cases were refuted by high-sensitive NGS. Also, heterogeneity among metastatic deposits was concluded only for PIK3CA in 2 patients. Similarly, primary-to-metastatic heterogeneity was indicated in 8 of 78 patients (10%) using Sanger sequencing but for only 2 patients after NGS, showing the emergence of 1 KRAS and 1 PIK3CA mutation in the metastatic lesions. KRAS mutations were present in 53 of 106 patients (50%) and were associated with poorer 3-year CSS after liver resection (37% vs. 61% for KRAS wild-type; P = .004). Poor prognostic associations were found also for the combination of KRAS/NRAS/BRAF mutations compared with triple wild-type (P = .002).
Intra-patient mutation heterogeneity was virtually undetected, both between the primary tumor and the liver metastases and among the metastatic deposits. KRAS mutations separately, and KRAS/NRAS/BRAF mutations combined, were associated with poor patient survival after partial liver resection.
多发性结直肠癌肝转移患者基因异质性的患病率及其临床意义在很大程度上仍不清楚。在一系列接受结直肠癌肝转移切除术的前瞻性患者中，目的是研究KRAS、NRAS、BRAF和PIK3CA基因突变的转移灶间及原发灶与转移灶间的异质性及其预后影响。
我们通过临床常规检测、桑格测序、二代测序（NGS）和/或数字液滴聚合酶链反应，分析了106例患者的372个肝转移灶和78个原发肿瘤的突变状态。采用Kaplan-Meier法分析3年癌症特异性生存率（CSS）。
尽管桑格测序显示97例患者中有14例（14%）存在转移灶间突变异质性，但几乎所有病例均被高灵敏度NGS否定。同样，仅在2例患者中发现PIK3CA转移灶间存在异质性。类似地，采用桑格测序时，78例患者中有8例（10%）存在原发灶与转移灶间异质性，但NGS后仅2例患者存在，表现为转移灶中出现1个KRAS和1个PIK3CA突变。106例患者中有53例（50%）存在KRAS突变，且与肝切除术后较差的3年CSS相关（KRAS野生型为61%，KRAS突变型为37%；P = 0.004）。与三联野生型相比，KRAS/NRAS/BRAF突变组合也显示出不良预后相关性（P = 0.002）。
在患者体内，无论是在原发肿瘤与肝转移灶之间还是在转移灶之间，几乎未检测到突变异质性。KRAS单独突变以及KRAS/NRAS/BRAF联合突变与部分肝切除术后患者的不良生存相关。
