生长分化因子15在甲状腺乳头状癌中的表达及其临床意义

Expression of growth differentiation factor 15 in papillary thyroid carcinoma and its clinical significance

目的探讨生长分化因子15(GDF-15)在甲状腺乳头状癌(PTC)中的表达及临床意义。方法收集2019年1月至2月在湖南中医药大学第一附属医院行甲状腺癌根治术的3例PTC患者的肿瘤组织及淋巴结转移灶组织,使用高通量测序筛选差异表达基因;收集20例PTC患者肿瘤原发灶及淋巴结转移灶,用于验证测序结果;另收集20例PTC原发灶及癌旁组织(距肿瘤边缘>2 cm),用于验证目的基因在肿瘤组织及癌旁组织的表达情况;同时收集湖南中医药大学第一附属医院2014年1月至12月行甲状腺癌根治术PTC患者病理标本64例,其中31例患者伴淋巴结转移。采用实时荧光定量聚合酶链反应(qRT-PCR)检测GDF-15的表达情况,验证测序结果;采用免疫组织化学法检测GDF-15蛋白在PTC原发灶、癌旁组织以及淋巴结转移灶组织中表达水平。根据GDF-15蛋白在PTC患者原发灶组织中的表达,将其分为高表达组(35例)与低表达组(29例),分析GDF-15表达水平与患者临床病理特征的关系;Kaplan-Meier法分析两组患者5年无瘤生存率。结果 3例PTC原发灶与转移灶组织mRNA高通量测序结果显示,前10位差异表达基因为CDH2、CDF15、DKK1、GLIPR1、PCDH7、ID3、FBN1、MYPN、UBASH3B、CCDC80。20例PTC原发灶组织及癌旁组织中GDF-15 mRNA表达量分别为4.1±0.5、2.8±0.3,差异有统计学意义(t=2.220,P=0.032)。另20例PTC原发灶及淋巴结转移灶组织中GDF-15 mRNA表达量分别为3.1±0.4、5.8±0.7,差异有统计学意义(t=3.556,P=0.001)。免疫组织化学结果显示,GDF-15在癌旁组织、PTC原发灶及转移灶中免疫组织化学评分分别为(4.0±0.3)分、(6.1±0.3)分和(9.0±0.4)分,PTC原发灶与癌旁组织、转移灶与癌旁组织、转移灶与原发灶组织GDF-15蛋白表达比较,差异均有统计学意义(均P<0.01)。GDF-15高表达组与低表达组患者肿瘤长径、肿瘤T分期、肿瘤N分期构成比比较,差异均有统计学意义(均P<0.05);GDF-15高表达组患者5年无瘤生存率为60%,低表达组为83%,差异有统计学意义(P=0.033)。结论 GDF-15在癌旁组织、PTC组织及淋巴结转移灶组织中表达逐渐增高,且其表达水平与患者肿瘤进展、复发、转移相关,可作为潜在的临床判断预后的预警分子及治疗靶点。

Objective To investigate the expression and clinical significance of growth differentiation factor 15(GDF-15)in papillary thyroid carcinoma(PTC).Methods The tumor tissues and metastatic lymph node tissues of 3 PTC patients who underwent radical surgery of thyroid cancer in the First Hospital of Hunan University of Chinese Medicine from January to February 2019 were collected,and the differential expressed genes were screened by high-throughput sequencing;20 cases of primary tumor tissues and metastatic lymph node tissues were collected to verify the sequencing results.Another 20 cases of primary PTC tissues and adjacent tissues(>2 cm away from the tumor edge)were collected to verify the expression of target genes in tumor tissues and adjacent tissues.Sixty-four pathological specimens of PTC patients who underwent radical surgery of thyroid cancer in the First Hospital of Hunan University of Chinese Medicine from January to December 2014 were collected,of which 31 patients had lymph node metastasis.The real-time fluorescent quantitative polymerase chain reaction(qRT-PCR)was used to detect the expression of GDF-15 and verify the sequencing results;immunohistochemistry was used to detect the expression of GDF-15 protein in the primary PTC tissues,adjacent tissues and metastatic lymph node tissues.According to the expression of GDF-15 protein in the primary tumor tissues of PTC patients,the patients were divided into high-expression group(35 cases)and low-expression group(29 cases),and the relationship between GDF-15 expression level and clinicopathological characteristics of patients was analyzed;Kaplan-Meier method was used to analyze the 5-year tumor-free survival rate of the two groups.Results The mRNA high-throughput sequencing results of 3 cases of PTC primary and metastatic tissues showed that the top 10 differential expressed genes were CDH2,CDF15,DKK1,GLIPR1,PCDH7,ID3,FBN1,MYPN,UBASH3B and CCDC80.The expression of GDF-15 mRNA in 20 cases of PTC primary tumor tissues and adjacent tissues were 4.1±0.5 and 2.8±0.3,and the difference was statistically significant(t=2.220,P=0.032).The expression of GDF-15 mRNA in another 20 cases of PTC primary tumor tissues and metastatic lymph node tissues were 3.1±0.4 and 5.8±0.7,and the difference was statistically significant(t=3.556,P=0.001).The results of immunohistochemistry showed that GDF-15 had the immunohistochemical scores of(4.0±0.3)points,(6.1±0.3)points and(9.0±0.4)points in PTC adjacent tissues,primary tumor tissues and metastasis tissues.The expressions of GDF-15 protein between PTC primary tumor tissues and adjacent tissues,metastatic tissues and adjacent tissues,and metastatic tissues and primary tumor tissues were significantly different(all P<0.01).The differences in composition ratios of tumor long-axis diameter,tumor T stage and N stage between GDF-15 high-expression group and low-expression group were statistically significant(all P<0.05).The 5-year tumor-free survival rates in GDF-15 high-expression group and low-expression group were 60%and 83%,and the difference was statistically significant(P=0.033).Conclusions The expressions of GDF-15 in PTC adjacent tissues,tumor tissues and metastatic lymph node tissues gradually increase,and its expression level is related to tumor progression,recurrence and metastasis.It can be used as a potential clinical prognostic warning molecule and therapeutic target.