Abstract：
BACKGROUND: The CDKN2A gene is frequently affected by somatic copy number variations (SCNVs, including deletions and amplifications [SCNdel and SCNamp]) in the cancer genome. Using surgical gastric margin tissue samples (SMs) as the diploid reference in SCNV analysis via CDKN2A/P16-specific real-time PCR (P16-Light), we previously reported that the CDKN2A SCNdel was associated with a high risk of metastasis of gastric carcinoma (GC). However, the status of CDKN2A SCNVs in SMs and their clinical significance have not been reported.
METHODS: Peripheral white blood cell (WBC) and frozen GC and SM tissue samples were collected from patients (n = 80). Droplet digital PCR (ddPCR) was used to determine the copy number (CN) of the CDKN2A gene in tissue samples using paired WBCs as the diploid reference.
RESULTS: A novel P16-ddPCR system was initially established with a minimal proportion (or limit, 10%) of the detection of CDKN2A CN alterations. While CDKN2A SCNamp events were detected in both SMs and GCs, fewer CDKN2A SCNdel events were detected in SMs than in GCs (15.0% vs. 41.3%, P = 4.77E-04). Notably, significantly more SCNamp and fewer SCNdel of the CDKN2A gene were detected in SMs from GC patients without metastasis than in those from patients with lymph node metastasis by P16-ddPCR (P = 0.023). The status of CDKN2A SCNVs in SM samples was significantly associated with overall survival (P = 0.032). No cancer deaths were observed among the 11 patients with CDKN2A SCNamp.
CONCLUSIONS: CDKN2A SCNVs in SMs identified by P16-ddPCR are prevalent and significantly associated with GC metastasis and overall survival.
METHODS: Peripheral white blood cell (WBC) and frozen GC and SM tissue samples were collected from patients (n = 80). Droplet digital PCR (ddPCR) was used to determine the copy number (CN) of the CDKN2A gene in tissue samples using paired WBCs as the diploid reference.
RESULTS: A novel P16-ddPCR system was initially established with a minimal proportion (or limit, 10%) of the detection of CDKN2A CN alterations. While CDKN2A SCNamp events were detected in both SMs and GCs, fewer CDKN2A SCNdel events were detected in SMs than in GCs (15.0% vs. 41.3%, P = 4.77E-04). Notably, significantly more SCNamp and fewer SCNdel of the CDKN2A gene were detected in SMs from GC patients without metastasis than in those from patients with lymph node metastasis by P16-ddPCR (P = 0.023). The status of CDKN2A SCNVs in SM samples was significantly associated with overall survival (P = 0.032). No cancer deaths were observed among the 11 patients with CDKN2A SCNamp.
CONCLUSIONS: CDKN2A SCNVs in SMs identified by P16-ddPCR are prevalent and significantly associated with GC metastasis and overall survival.
摘要：
背景：CDKN2A基因经常受到体细胞拷贝数变异的影响（SCNVs，包括癌症基因组中的缺失和扩增[SCNdel和SCNamp]）。通过CDKN2A/P16特异性实时PCR（P16-Light），在SCNV分析中使用手术胃缘组织样品（SMs）作为二倍体参考，我们先前报道了CDKN2ASCNdel与胃癌（GC）转移的高风险相关。然而,SMs中CDKN2ASCNVs的状态及其临床意义尚未见报道。
方法：从患者（n=80）收集外周血白细胞（WBC）和冷冻GC和SM组织样本。使用配对的WBC作为二倍体参考,使用液滴数字PCR(ddPCR)来确定组织样品中CDKN2A基因的拷贝数(CN)。
结果：最初以最小比例（或限制，10%)的检测CDKN2A一CN的变更。虽然在SM和GC中均检测到CDKN2ASCNamp事件，在SM中检测到的CDKN2ASCNdel事件少于GC（15.0%vs.41.3%,P=4.77E-04)。值得注意的是,通过P16-ddPCR，在无转移的GC患者的SM中检测到的SCNamp和CDKN2A基因的SCNdel明显多于有淋巴结转移的患者（P=0.023）。SM样本中CDKN2ASCNVs的状态与总生存期显著相关(P=0.032)。在11例CDKN2ASCNamp患者中未观察到癌症死亡。
结论：通过P16-ddPCR鉴定的SMs中的CDKN2ASCNVs普遍存在，并且与GC转移和总生存期显著相关。
方法：从患者（n=80）收集外周血白细胞（WBC）和冷冻GC和SM组织样本。使用配对的WBC作为二倍体参考,使用液滴数字PCR(ddPCR)来确定组织样品中CDKN2A基因的拷贝数(CN)。
结果：最初以最小比例（或限制，10%)的检测CDKN2A一CN的变更。虽然在SM和GC中均检测到CDKN2ASCNamp事件，在SM中检测到的CDKN2ASCNdel事件少于GC（15.0%vs.41.3%,P=4.77E-04)。值得注意的是,通过P16-ddPCR，在无转移的GC患者的SM中检测到的SCNamp和CDKN2A基因的SCNdel明显多于有淋巴结转移的患者（P=0.023）。SM样本中CDKN2ASCNVs的状态与总生存期显著相关(P=0.032)。在11例CDKN2ASCNamp患者中未观察到癌症死亡。
结论：通过P16-ddPCR鉴定的SMs中的CDKN2ASCNVs普遍存在，并且与GC转移和总生存期显著相关。
