CNE、SPC—A1和MCF—7人类肿瘤细胞Ku80基因同源性研究

目的：研究人鼻咽鳞癌(CNE)、肺腺癌(SPC—A1)和乳腺腺癌(MCF—7)细胞Ku80基因功能区的保守性，探讨该基因突变与肿瘤放射和化学治疗疗效的关系。方法：采用聚合酶链式反应和克隆技术测定3种肿瘤细胞内与DNA损伤修复有关的Ku80基因序列，分析他们的功能区保守性变化，模拟和比较突变产物亲疏水性差异。结果：人CNE、SPC—A1和MCF—7肿瘤细胞Ku80基因同源性分别为99．95％、99．5％和99．7％，包括碱基转换和颠换突变。部分突变碱基导致产物氨基酸替代并影响他们的亲疏水结构。SPC-A1细胞发生150aa Ile→Vao、470aa Asp→Gly、553aa Phe→Ile替代和570aaGln→0缺失；MCF-7细胞发生209aa Lys→Glu、 23laa Leu→Arg和297aa→Ser替代；而CNE细胞功能区高度保守。结论：SPC-A1和MCF-7细胞Ku80p功能区存在氨基酸替代，影响其结构和活性变化，与肿瘤细胞DNA双链断裂损伤修复能力和肿瘤放化疗疗效直接相关。     

人肿瘤细胞系LigaseⅣ基因突变与放射敏感性的关系研究

目的研究人肿瘤细胞DNA-LigaseⅣ基因突变与放射敏感性的关系.方法常规集落形成方法测定人鼻咽鳞癌(CNE)、肺腺癌(SPC-A1)和乳腺腺癌(MCF-7)细胞系不同剂量照射后的细胞存活分数,采用聚合酶链式反应和克隆技术测定3种细胞参与DNA损伤修复的DNA ligaseⅣ基因序列,分析它们的同源性变化和突变对基因产物亲疏水性的影响.结果 3种细胞存活参数比较存在较大差异,CNE细胞较SPC-A1和MCF-7细胞显示出较高的放射敏感性.CNE、SPC-A1和MCF-7细胞LigaseⅣ基因同源性分别为99.95%、99.99%和99.98%,包括碱基转换和颠换突变.部分突变碱基导致氨基酸替代并影响基因产物的亲疏水结构.CNE细胞LigaseⅣp的313aa His→Arg、538aa Gly→Arg、579aa Lys→Arg和585aa Asn→Ser替代与CNE细胞放射敏感性高于SPC-A1和MCF-7细胞有关.结论 LigaseⅣp在非同源性末端连接(NHEJ)途径中起关键和最终连接作用,该基因突变影响肿瘤细胞的双链断裂损伤修复能力和放射敏感性.     

α-粒子诱发BEP2D细胞恶性转化中DNA修复基因DNA-PK的表达和突变分析

目的: 研究α-粒子诱发人支气管上皮细胞(BEP2D)恶性转化中DNA修复基因DNA-PK的结构和表达变化.方法:用Northern blot杂交检测基因转录水平,聚合酶链式反应-单链构象多态性(PCR-SSCP)分析基因编码序列结构变化.结果:癌变细胞中DNA修复基因Ku70(XRCC-6)的编码碱基发生突变,第1 148～1 153位点由AGGATC突变为GAGTAC,致使编码的氨基酸由RI变为EY;细胞恶性转化过程中,DNA修复基因DNA-PKcs(XRCC-7)的表达发生改变,在恶性转化早期即α-粒子照射后第21代就已被抑制,但发生癌变(第35代)后,部分细胞克隆的该基因表达又重新上调.结论:DNA修复基因DNA-PK的结构和表达的变化,导致细胞DNA修复能力缺陷,基因组不稳定性增加,是α-粒子癌变的分子机制之一.     

不同敏感性鼻咽癌细胞株中Ku蛋白表达情况比较

目的　比较作为DNA双链断裂修复蛋白DNA依赖性蛋白激酶 (DNA PK)的调节亚基70 Ku、80 Ku在不同放射敏感性鼻咽癌细胞株CNE1和CNE2中的表达情况。方法　成克隆实验测定鼻咽癌高分化鳞癌细胞CNE1和低分化鳞癌细胞CNE2不同剂量照射后的存活分数 ,用线性二次模型拟合剂量存活曲线并求出放射生物学参数α、β、SF2、MID以评价两株细胞的放射敏感性。Westernblot检测照射前和后不同时间及不同剂量CNE1、CNE2细胞中Ku的表达 ,检测蛋白条带的吸光度值做半定量分析。结果　CNE1在各个剂量点的存活分数均比CNE2高 ,MID也大于CNE2 (2 .35∶1.11) ,SF2也大于CNE1(0 .5 4∶0 .37)。Westernblot显示两株细胞中70 Ku、80 Ku均有表达 ,蛋白条带的吸光度值测定显示70 Ku在CNE1、CNE2细胞中分别为 2 0 .0 3± 7.5 6和 19.36± 6 .0 4 ,80 Ku分别为 2 5 .98± 12 .87和 2 3.74±9.2 4 (P值均 >0 .0 5 )。蛋白表达的定量和定性分析同样显示 4Gy照射后不同时间点及 0～ 16Gy照射后 12hKu的表达无统计学差异。结论　实验验证了CNE2比CNE1对放射更敏感 ;照射前后两个细胞均有70 Ku、80 Ku蛋白表达且无差异 ;CNE1、CNE2放射敏感性的差异与Ku蛋白表达量无明显关系。     

Ku蛋白与肿瘤放射敏感性

 Ku是由Ku70和Ku80两个亚基组成的异质二聚体蛋白,它与DNA依赖蛋白激酶催化亚单位(DNA-PKcs)共同组成DNA依赖的蛋白激酶。射线杀伤肿瘤细胞主要通过破坏DNA双链,导致DNA损伤不能修复,从而引起细胞凋亡。Ku蛋白是DNA损伤修复中的关键因子,通过阻断Ku蛋白能够增加肿瘤细胞的放射敏感性。     

“彗星” 法分析人肿瘤细胞DNA放射损伤和修复

探讨“彗星”分析法 (CA)在检测体外培养人肿瘤细胞DNA放射损伤与修复和放射敏感性的关系。方法　采用碱性CA检测鼻咽高分化鳞癌上皮细胞系 (CNE 1)、食管鳞癌上皮细胞系 (Ec 10 9)、肺腺癌细胞系 (GLC)和胃低分化腺癌细胞系 (BGC 82 3)经 6MVX射线照射后单细胞内DNA单链断裂 (SSB)程度及其与放射剂量的关系 ,以及CNE 1和GLC细胞系在分别接受了 16GyX射线照射后的自身修复情况 ,同时与相应的细胞存活曲线比较。结果　碱性CA可以检测出 4个细胞系DNA的SSB ,并与放射剂量呈良好的线性关系。 16Gy剂量下各细胞系的SSB程度依次为CNE 1>Ec 10 9>GLC >BGC 82 3。CNE 1,Ec 10 9,GLC和BGC 82 3细胞系的Do值分别为 1.2 5 ,1.2 7,1.88和 1.5 6。 16Gy诱导CNE 1和GLC细胞系的DNA损伤后 ,其半修复时间分别为 7.4,17.8min。结论　采用碱性CA能确切反映 4种人肿瘤细胞系DNA的定量损伤程度及其与放射剂量的关系 ,并能确切反映辐射损伤后自身修复能力 (CNE 1和GLC)在受测时间中的定量变化情况。自身修复能力的大小在鳞癌和腺癌细胞系间与放射敏感性的大小 (Do值 )有较好的对应关系。     

鼻咽癌中KLF6基因突变的检测

背景与目的：鼻咽癌（nasopharyngeal carcinoma,NPC)高发于中国南方和东南亚地区,其发病是一个多因素,多步骤的过程,与遗传因素,EB病毒感染和环境因子有关,但分子机理仍不清楚,KLF6基因编码一种广泛表达的核转录因子,在某些前列腺癌肿瘤中发现有高频的等位基因的丢失和基因突变,本研究通过对KLF6基因在NPC肿瘤中的突变检测,探讨KLF6基因与NPC发病的关系。方法：采用PCR-直接测序分析方法。在19例散发性NPC组织细胞和3个NPC细胞系（CNE1,CNE2,SUNE1）中对KLF6编码区和拼接位点进行检测。结果：在3你散发性NPC肿瘤组织DNA中检测到KLF6基因的3个不同位置的错义改变,分别为GAG→TG（Glu75Val),AGG→AGG（Ser136Arg)和AGA→AAA（Arg243Lys),在50个随机正常个体（100条染色体）和3个NPC细胞系中没有发现这3个位点的碱基变异,结论：这3个变异可能是KLF6基因的新的突变位点,在某些NPC发病中可能有作用。     

DNA修复基因XRCC1多态性与肺癌易感性研究进展

X线修复交叉互补基因1（XRCC1）是一种重要的DNA修复基因，参与DNA单链断裂和碱基损伤修复，其编码的蛋白质在碱基修复过程中是不可缺少的。该基因的多态性会导致相应的氨基酸改变，从而影响DNA修复，可能引起肿瘤的易感性。XRCC1基因多态性与吸烟交互作用对肺癌易感性的关系仍然存在争论，其相关性需进一步深入研究。     

RNA干扰DNA修复提高肿瘤细胞的放疗敏感性

放射性抵抗是目前肿瘤放射治疗中难以解决的一大难点。放射损伤的作用靶点为DNA, DNA损伤后,会启动自身的修复系统进行修复,能针对自身不同类型的DNA损伤启动不同修复机制,DNA的修复在一定程度上导致了放疗抵抗的发生。近年来,RNA干扰在肿瘤、病毒性疾病和遗传病等基因治疗研究方面均取得了一定的成果,早在1968年,Alexander就提出了细胞辐射敏感性取决于其DNA链断裂修复能力的概念。相关研究证明,通过构建表达dsRNA或者siRNA来干扰DNA修复蛋白,如Ku二聚体(Ku70和Ku80)、DNA-PKcs、Ku、ATM、Rad51、BRCA1、P53、XRCC4等的表达,联合放疗,都在不同程度上增加了放疗的敏感性。本文就RNA干扰DNA修复促进肿瘤细胞放疗敏感性的研究进展作一综述,并对其应用于肿瘤临床治疗的前景提出展望。     

辐射所致残存染色体易位与放射敏感性关系研究

目的：应用荧光原位杂交（FISH）方法研究人肿瘤细胞放射敏感性与染色体残存易位关系及临床应用的可行性。方法：采用3种放射敏感性不同的人肿瘤细胞系：鼻咽鳞癌（CNE）、肺腺癌（SPC）和乳腺腺癌（MCF-7）。通过克隆形成方法测定2Gy,4Gy,6Gy和8GyX线照射剂量下肿瘤细胞的存活率。采用常规染色体片过程和2号染色体涂染探针及FISH方法。测定2Gy,4Gy和6GyX线照射24h后，肿瘤细胞2号染色体内在和诱导的畸变量。结果：未照射的对照细胞2号染色体存在不同程度的内在畸变，2Gy,4Gy和6Gy照射后24h,CNE、SPC和MCF-7细胞诱导生成的残存染色体畸变与剂量关系一致，能够反映细胞的放射敏感性，所有细胞系诱导2号染色体生成的畸变与细胞存活率均存在良好相关性（rs=0.96)。结论：诱导的残存染色体畸变与照射剂量呈线性关系，采用FISH方法计数照射诱导的残存染色体畸变，可以预测肿瘤细胞间的放射敏感性差异并具有重要的临床意义。     

Twinning and the Incidence of Breast and Gynecological Cancers (United States)

Increasing epidemiological and experimental evidence indicates that the carcinogenic pathway in the breast and female reproductive organs is driven, at least in part, by factors associated with reproduction. We conducted a retrospective cohort study, comparing the risk of ovarian, breast, endometrial, and cervical cancers among women who had records of at least one twin pregnancy, compared with women who had given birth to only single children. Subjects were selected from the Utah Population Database, which consists of multiple linked datasets including genealogy, births and deaths and cancer registries. We used Poisson regression to calculate relative risks, adjusted for the number of pregnancies and the age of the mother at the birth of first and last children, with singleton mothers as the reference group in each case. The risks of breast and ovarian cancers did not differ between mothers of twins and mothers of single children. The risk of endometrial cancer was slightly lower in mothers of twins than in mothers of singleton children (RR = 0.90, 95% CI 0.67-1.21). Conversely the risk of cervical cancer was higher among twin mothers (RR = 1.78, 95% CI 0.88-3.52). This latter finding supports previous data suggesting that reproductive hormones act as cofactors in the etiology of cervical cancer.     

A blueprint for cancer screening and early detection: Advancing screening’s contribution to cancer control

From the mid-20th century, accumulating evidence has supported the introduction of screening for cancers of the cervix, breast, colon and rectum, prostate (via shared decisions), and lung. The opportunity to detect and treat precursor lesions and invasive disease at a more favorable stage has contributed substantially to reduced incidence, morbidity, and mortality. However, as new discoveries portend advancements in technology and risk-based screening, we fail to fulfill the greatest potential of the existing technology, in terms of both full access among the target population and the delivery of state-of-the art care at each crucial step in the cascade of events that characterize successful cancer screening. There also is insufficient commitment to invest in the development of new technologies, incentivize the development of new ideas, and rapidly evaluate promising new technology. In this report, the authors summarize the status of cancer screening and propose a blueprint for the nation to further advance the contribution of screening to cancer control.     

Risk factors for colorectal cancer following breast cancer

Objective. To investigate risk factors for colorectal cancer following breast cancer. Methods. In this nested case-control study, all women (n=14,900) with a first primary breast cancer (1978–1992) were identified from the western Washington population-based Surveillance, Epidemiology, and End Results Cancer Registry. Cases (n=160) developed a second primary colorectal cancer before 1995, at least 6 months after the first cancer diagnosis. Controls (n=310, matched to the cases on calendar year, age and breast cancer stage) were randomly selected from those who did not develop a second primary cancer and who survived to the case's colorectal cancer diagnosis date. Characteristics of the cases and controls at initial diagnosis were compared using conditional logistic regression. Results. The incidence of colorectal cancer was associated with a family history of breast cancer (v.s. no family history, matched odds ratio (mOR)=2.1, 95% confidence interval (CI): 1.1–4.1), high body mass index (30 kg/m² v.s. <30 kg/m², mOR=2.2, CI: 1.2–3.9), and lobular breast cancer histology (v.s. ductal, mOR=2.0, CI: 0.9–4.4). Risk was unrelated to menopausal status, prior hormone replacement therapy and estrogen/progesterone receptor status of the breast tumors. Conclusions. The risk of developing a second primary colorectal cancer may be elevated among certain subsets of breast cancer patients.     

结直肠神经内分泌肿瘤的研究进展

结直肠神经内分泌肿瘤来源于结直肠神经内分泌细胞,发病率较低,但近年有上升趋势.WHO病理学将结直肠神经内分泌肿瘤分为神经内分泌瘤、神经内分泌癌、混合型腺-神经内分泌癌和增生性及肿瘤前病变.结直肠神经内分泌肿瘤细胞具有激素合成及分泌功能,但不一定都出现相应的临床症状.不同分类、分期的结直肠神经内分泌肿瘤的诊断及治疗方法也...     

Neoplasms in skin and subcutis over the breast, simulating breast neoplasms: case reports and literature review

Twenty cases of neoplasms in skin and subcutaneous tissue over the breast were reviewed. There were 17 women, from 15 to 70 years of age, and three men, from 25 to 66 years of age. Among the benign skin neoplasms, superficial leiomyoma, granular cell tumor, and eccrine acrospiroma were misdiagnosed clinically as primary breast carcinoma. Among the malignant neoplasms in subcutaneous tissue, there were three metastatic malignant melanomas, one metastatic epidermoid bronchogenic carcinoma, and two malignant lymphomas. It is interesting that four of these six patients had no prior history of malignant lesion, the subcutaneous nodule presenting as the first manifestation of an occult primary. It is concluded that histological diagnosis of such tumors may lead to avoidance of unnecessary radical surgery.     

从高发现场视角看食管癌和贲门癌的临床研究趋势

我院流行病室开展食管癌和贲门癌高发现场研究已历30余年,所取得的最显著成绩主要有以下4个方面：（1）对食管癌癌前病变（即鳞状上皮不典型增生）及其逐级发展和演变规律的确认,以及对各级不典型增生诊断及处理的经验;（2）对食管癌早诊早治方法的探索,以及实践所得的优异效果;（3）食管鳞状细胞癌易发部位的发现及其对食管癌早期诊断的贡献;（4）胃贲门癌高发位点的发现及其对贲门癌早诊早治的贡献。在此基础上,结合我们长期在高发现场的实际工作经验,展望今后食管癌和贲门癌临床研究的趋势。     

子宫颈癌放疗后子宫体恶性肿瘤47例临床分析

Objective  To study the characteristics and clinical features of uterine neoplasms developed after radiation therapy for cervical carcinoma. Methods  Clinical data of 47 cases of uterine neoplasms occurred following radiation therapy for cervical carcinoma were retrospectively reviewed. Results  The median age at uterine neoplasms diagnosis was 62 years (range: 38–77 years), and the median latency period from initial therapy to development of uterine neoplasms was 14 years (range: 5–35 years). Thirty of 47 cases were endometrial carcinoma, of which 3 were uterine papillary serous carcinoma (UPSC). Seventeen of 47 patients were uterine sarcoma, all of those were carcinosarcoma. The distribution by stage, grade, and histology of 30 cases of endometrial carcinoma was as follows: stage Ib, 1 case; stage Ic, 2 cases; stage II, 6; stage IIIa, 4; stage IIIb, 2; stage IIIc, 11; stage IV, 4 cases; grade 1, two cases; grade 2, nine; grade 3 (include 3 UPSC patients), seventeen; unknown grade, two; endometriod, 27; UPSC, 3 cases; 7 of 30 cases of endometrial carcinoma had recurrences (23.3%), at median time to recurrence was 24 months, and their median survival time was 26 months. The overall 3- and 5-year survival rates were 60% and 38%, respectively. Of the 17 cases of uterine sarcoma, the median survival was 10 months, 6 patients occurred recurrence (35.9%), at a median time to recurrence was 9 months, and their median survival was 6 months. The overall 3- and 5-year survival rates were 12% and 0, respectively. Conclusion  The main uterine neoplasms development after radiation therapy for cervical carcinoma is endometrial carcinomas, of which there is a preponderance of high-risk histological subtypes and a poor prognosis. Most of the uterine sarcomas occurred following radiation therapy for cervical carcinoma are carcinosarcomas and the prognosis is very poor.     

子宫颈癌放疗后子宫体恶性肿瘤47例临床分析

目的分析宫颈癌放疗后子宫体恶性肿瘤的临床特点。方法回顾性分析47例宫颈癌放疗后子宫体恶性肿瘤的临床资料。结果诊断宫体恶性肿瘤的中位年龄为62岁,放疗后至确诊发生肿瘤的中位时间为14年。47例中,子宫内膜癌30例,子宫中胚叶混合瘤17例。30例子宫内膜癌的FIGO分期为IB期1例,IC期2例,Ⅱ期6例,ⅢA期4例,ⅢB期2例,ⅢC期11例,Ⅵ期4例,Ⅱ期以上者占90%;病理高分化2例,中分化9例,低分化14例,不能分级者2例,浆液性乳头状腺癌3例;7例疗后复发,中位复发时间为24个月;中位生存时间为26个月,总3、5年生存率分别为60%、38%。17例子宫中胚叶混合瘤,中位生存10个月,6例疗后复发,中位复发时间9个月;复发者中位生存6个月,总3、5年生存率分别为12%、0。结论宫颈癌放疗后发生的肿瘤以内膜腺癌多见,内膜腺癌中具有高危因素者比例大,预后差;放疗后发生子宫肉瘤中以中胚叶混合瘤最常见,预后差。