抑癌基因ARHI与全身各系统肿瘤相关性及机制的研究进展

抑癌基因 ARHI（aplasia ras homologue I）是1999年新发现的母源性印迹基因。最近研究发现ARHI 具有抑制肿瘤细胞增殖、转移、侵袭,调控肿瘤细胞自噬等作用。另外,学者们还发现 ARHI 不仅与卵巢癌、乳腺癌、胰腺癌密切相关,而且还与其他生殖、消化、内分泌等全身各系统肿瘤具有相关性。本文就最近几年国内外对 ARHI 与全身各系统肿瘤的相关性及其机制的最新研究进展进行综述。     

肿瘤抑制基因ARHI的生物学功能及研究进展

肿瘤是一种基因病，抑癌基因在抵御肿瘤发生、发展中起着重要作用。ARHI(aplysia ras homolog I)／NOEY2是一个新发现的抑癌基因．是ras/rap超家族成员之一．与ras家族有50％～60％的同源性．位于人染色体1p31，属小GTP结合蛋白，是该家族第1个被报道的肿瘤抑制基因。ARHI基因编码的蛋白在人类多种组织表达，其中正常卵巢的ARHI表达最高。ARHI是一个印迹基因．印迹机制可能与其CpG岛的差异甲基化有关。ARHI参与细胞周期调控可能作用于cyclin D1，使其不能与CDK结合形成活性激酶，从而使细胞停止于G1期。ARHI可能通过依赖caspase和calpain两条途径参与信号通路传导诱发细胞凋亡。该基因的异常表达跟多种肿瘤的发生、发展有关。ARHI基因参与了乳腺癌的发生和发展，该基因的表达缺失可能与乳腺癌的转移机制有关。卵巢癌、乳腺癌存在广泛的1p31缺失，其中ARHI基因是最常见的一个缺失区域。ARHI基因和蛋白在胰腺癌组织中有较高比例的缺失，提示该基因和蛋白在胰腺癌的发生中起一定作用。ARHI基因在膀胱癌、肝癌、前列腺癌等其他肿瘤中也有不同程度的表达异常。     

肿瘤抑制基因ARHI的生物学功能及研究进展

肿瘤是一种基因病,抑癌基因在抵御肿瘤发生、发展中起着重要作用。ARHI(aplysia ras hom olog I)/NOEY2 是一个新发现的抑癌基因,是 ras/rap超家族成员之一,与 ras家族有50%~60%的同源性,位于人染色体1p31,属小GTP结合蛋白,是该家族第1个被报道的肿瘤抑制基因。ARHI基因编码的蛋白在人类多种组织表达,其中正常卵巢的ARHI表达最高。ARHI是一个印迹基因,印迹机制可能与其CpG岛的差异甲基化有关。ARHI 参与细胞周期调控可能作用于cyclin D1 ,使其不能与 CDK结合形成活性激酶,从而使细胞停止于 G1 期。AR HI可能通过依赖caspase和 calpain两条途径参与信号通路传导诱发细胞凋亡。该基因的异常表达跟多种肿瘤的发生、发展有关。ARHI基因参与了乳腺癌的发生和发展,该基因的表达缺失可能与乳腺癌的转移机制有关。卵巢癌、乳腺癌存在广泛的1p31缺失,其中 ARHI 基因是最常见的一个缺失区域。ARHI基因和蛋白在胰腺癌组织中有较高比例的缺失,提示该基因和蛋白在胰腺癌的发生中起一定作用。ARHI基因在膀胱癌、肝癌、前列腺癌等其他肿瘤中也有不同程度的表达异常。     

抑癌基因ARHI研究进展

ARHI（aplasia ras homologue member I）/NOEY2是1999年新发现的一个母源性抑癌印迹基因,位于人染色体1p31,编码一个相对分子量为26kD的小GTP结合蛋白。ARHI属ras/rap超家族成员,与该家族成员有50%～60%的同源性并且两者具有相似的GTP/GDP结合域,但与该家族其它成员不同,ARHI发挥抑癌基因作用,是该家族第一个被报道的肿瘤抑制基因。ARHI基因编码的蛋白在人类多种组织表达,而该基因在人卵巢癌、乳腺癌、胰腺癌、肝癌等多种肿瘤中表达下调或缺失,提示其与上述肿瘤的发生、发展密切相关。ARHI可能通过作用于cyclin D1,使其不能与CDK结合形成活性激酶,从而使细胞停止于G1期来参与细胞周期调控;可能通过依赖caspase和calpain两条途径参与信号通路传导诱发细胞凋亡;另外,该基因可通过抑制STAT3的激活而发挥抑癌基因功能,也可以调节自体吞噬和肿瘤细胞休眠。目前研究显示,ARHI基因的表达缺失主要通过遗传事件和表观遗传学机制发生,包括DNA甲基化异常、杂合性丢失,乙酰化组蛋白的低水平表达及基因突变有关,但有待进一步深入研究。可以预见,ARHI基因的深入研究必将为早期肿瘤的基因诊治提供新的思路和理论依据。      

ARHI基因对人胰腺癌组织血管生成的影响

目的 探讨ARHI基因与胰腺癌组织血管密度和临床病理的相关性.方法 收集23例胰腺癌石蜡标本作为实验组,27例正常胰腺石蜡标本作为对照组.然后采用免疫组化方法检测两组标本ARHI、CD34蛋白表达情况;分析ARHI、CD34蛋白表达与胰腺癌的关系;分析ARHI与MVD的相关性.结果 对照组和实验组标本中ARHI阳性率分别为88.9%(24/27)、21.7%(5/23),实验组标本中ARHI基因表达下降,两组比较差异具有统计学意义(P<0.05);对照组MVD值显著低于实验组,差异具有统计学意义(P<0.05);ARHI表达与胰腺癌分化程度呈负相关(P<0.05),其中肿瘤分化程度越低,ARHI表达缺失概率越大;实验组标本中CD34阳性表达较高,多数具有管腔结构,且MVD值明显高于对照组标本,差异具有统计学意义(P<0.001);胰腺癌组织中,MVD与ARHI的表达无相关性(P>0.05);而所有统计病例中,ARHI阴性者比阳性者的MVD值高,且MVD与ARHI的表达呈负相关(P<0.001).结论 ARHI可能通过抑制胰腺癌微血管的生成进而抑制胰腺癌生长.     

肿瘤抑制基因PTEN的研究现状

肿瘤抑制基因PTEN是1997年由三个研究小组发现,现统称为PTEN。PTEN包括N端、C2区域和C端区域。其主要结构功能区位于N端,编码的蛋白与张力蛋白、辅助蛋白同源,参与细胞生长及肿瘤细胞浸润、血管发生及肿瘤转移的调节;并具有磷酸酶活性,参与细胞调控。PTEN的C端可调节PTEN稳定性和酶活性。其C2区域参与正确定位PTEN的催化结构域。PTEN可通过三磷脂酰肌醇激酶途径调节细胞周期;通过FAK途径抑制细胞的浸润、转移;通过蛋白激酶途径参与细胞转化和细胞周期调控。许多原发性肿瘤中都有PTEN缺失,但早期便发生完全缺失的只有子宫内膜癌和卵巢癌,其余病例中的完全失活发生在肿瘤后期,所以PTEN基因的缺失被认为是恶变过程中的后期事件。PTEN突变中有1/3是与以常染色体为主的疾病有关。     

Maspin在肿瘤中表达水平与抑瘤特性关系的研究进展

Maspin（mammary serine protease inhibitor）基因是一种丝氨酸蛋白酶抑制剂（serpin）基因,其编码的蛋白对肿瘤具有多方面的抑制作用：抑制新生血管的生成、增加细胞间的黏附性、抑制肿瘤细胞的侵袭和转移能力、诱导肿瘤细胞凋亡。在一些肿瘤如乳腺癌、前列腺癌组织中,Maspin表达水平随肿瘤的发展逐渐降低,在另一些肿瘤如胰腺癌组织呈高表达。Maspin在不同组织中的表达情况及生物学功能,仍需进一步研究。     

硫氧还蛋白与肿瘤转移

 硫氧还蛋白（Thioredoxin,Trx）是一类广泛存在于生物体内的抗氧化二硫还原蛋白,参与调节细胞内氧化还原平衡。近年研究发现,Trx在多种肿瘤组织中过表达,与肿瘤细胞增殖和凋亡以及细胞周期调控有关。Trx促进缺氧诱导因子（HIF）-1α的合成和稳定,与氧自由基的调控密切相关,参与肿瘤细胞的化疗耐药,在肿瘤转移中发挥重要作用,可能成为抑制肿瘤转移的新靶点。     

趋化因子CXCL14与肿瘤

CXCL14是趋化因子CXC家族的一个新成员,最早是从人类乳腺和肾脏组织中分离克隆出来的。CXCL14蛋白能参与调控体内许多生物学过程,如炎症免疫反应,肿瘤相关的血管生成,宿主对肿瘤特异免疫的激活以及肿瘤生长的自分泌调节等。CXCL14基因在正常组织中有表达,而在多种肿瘤细胞系及肿瘤组织中失表达。目前研究认为该基因属于肿瘤抑制基因,肿瘤中CXCL14蛋白的表达缺失与肿瘤的发生发展有关。本文综述有关CXCL14基因与肿瘤的研究进展。     

OLFM4与人消化系统肿瘤相关性的研究进展

人类嗅素蛋白（olfactomedin 4, OLFM4）属于olfactomedin相关家族成员,它是一种糖蛋白,正常表达于人的多种器官和组织。OLFM4在肿瘤组织中的表达具有特异性,它在胃癌、胰腺癌、结肠癌、宫颈癌等肿瘤中高表达。OLFM4有促进细胞增殖、调节细胞黏附转移、抑制细胞凋亡和免疫防御等多种功能。OLFM4与消化系统肿瘤的关系成为近年来的研究热点。OLFM4已被证明为胃癌发生、发展和分化的一个重要的标志物,但其具体调控机制目前仍处于研究中,抑制OLFM4基因表达和抗癌药物的联合应用可能成为胃癌的治疗策略。OLFM4在胰腺癌中的高表达率提示其或许可成为胰腺癌新的标志物,OLFM4是通过作用于DNA合成的S期到有丝分裂的G2/M期来促进胰腺癌细胞增殖。OLFM4基因最早是因为其在结肠癌细胞中的高表达被发现,OLFM4在结直肠癌的黏附转移中发挥着一定作用。OLFM4在早期消化系统肿瘤中的敏感性比其他肿瘤标志物高,是否能作为早期诊断消化系统肿瘤的标志物,有待于进一步研究。     

Chordoma: natural history and treatment results in 33 cases

Thirty-three chordomas were observed at the Istituto Nazionale Tumori of Milan from 1933 to 1983: 27 sacrococcygeal, 3 spheno-occipital, and 3 vertebral. The male:female ratio was 2.7, and the median age was 63 yr for patients with sacrococcygeal and 35.2 yr for those with nonsacral chordomas. After pathologic reassessment, distinct cytologic patterns were found: physaliphorous, syncytial, and mixed subtypes, with variable degrees of cytologic atypia. However, no evident difference in survival was documented in relation to these cytohistologic features. Four cases had a prior traumatic fracture, and the pathogenetic role of trauma is stressed. Eight cases were operated with adequate surgery and only three recurred, whereas of 11 inadequate operations, 10 developed local relapse. However, follow-up for recent adequate operations is short. Radiation therapy seemed to be effective with adjuvant or palliative aims. No chemotherapeutic regimen achieved any result; one case had a short complete remission after cis-dichlorodiammineplatinum + vinblastine + bleomycin (PVB). This analysis confirms the possibility of achieving radicality with high resection of the sacrum for lesions confined below the second sacral vertebra. Nonsacral chordomas were all unresectable. The best treatment for unresectable lesions seems to be palliative surgery plus radiotherapy.     

Plasma thromboxane A2 and prostacyclin concentrations in squamous cell carcinoma of the head and neck

Circulating prostaglandins, including thromboxane A2 and prostacyclin, have been implicated as possible facilitative agents in the growth and dissemination of squamous cell carcinomas of the head and neck. The purpose of this study was to evaluate the relationship of plasma concentrations of these compounds to tumor stage and the effect of surgical resection on plasma prostaglandin levels. Blood samples were obtained from 40 patients with head and neck cancer. Ten treated patients were clinically disease-free (NED), and 30 patients with active disease were previously untreated at the time of this study. Plasma concentrations of thromboxane A2 and prostacyclin were measured by radioimmunoassay of their stable metabolites thromboxane B2 (TxB) and prostaglandin 6-keto-F1 (PGI). Platelet aggregation was performed with normal donor platelets (PRP) and normal control or patient plasma (PPP). TxB and TxB/PGI ratios were increased in T1N0M0 patients, compared with NED and with T4N0M0 primary lesions versus all other groups. With lymphatic and hematogenous metastases, TxB and TxB/PGI ratios fell to NED levels. ADP-induced platelet aggregation was significantly increased in head and neck cancer patients, compared with normal controls, and with T4N0M0 lesions, compared with NED. There were no significant differences in PGI levels. TxB, PGI, TxB/PGI, and platelet aggregometry did not change significantly with curative surgery. TxB and TxB/PGI interactions are involved in head and neck cancer. Changes in TxB and TxB/PGI may be related to increased platelet aggregation.     

Autophagic tumor stroma: Mechanisms and roles in tumor growth and progression

Macroautophagy (hereafter autophagy) is a cellular homeostatic mechanism that involves protein and organelle degradation, and has a number of connections to human physiology and diseases. Autophagy in tumor parenchyma acts as either a tumor‐promoting role or a tumor‐inhibiting role depending on the types and stages of tumors. In recent years, attention to autophagy in tumor stroma that is referred as “autophagic tumor stroma” has created a new paradigm to understand the role of autophagy in cancer. Here we propose that the autophagic tumor stroma is a phenomenon of adaptation at a certain stage of tumor development, and has a prominent role in tumor growth, progression and spread of tumors. This idea is supported by recent studies: (i) Autophagic tumor stroma is activated by hypoxia and cancer cells induced oxidative stress, when tumors grow to a certain stage; (ii) Autophagic tumor stroma aids in providing essential nutrients to malignant cells, remodeling the tumor microenvironment, increasing DNA damage, genetic instability and stemness in cancer cells, and decreasing the apoptotic sensitivity of cancer cells. The autophagic tumor stroma is therefore a significant determinant in tumor growth and progression and implicates an important target for cancer therapies.     

Surgery and radiation therapy in the management of craniopharyngiomas

Twenty-nine patients with histologically confirmed craniopharyngioma were treated from 1960 to 1978, inclusive. Twelve patients were below the age of 15 years, the remaining were adults. Seventy-five percent (9/12) of the patients below the age of 15 showed increased intracranial pressure at presentation and 58% (7/12) showed visual disturbances. In the adult group, 47% (8/17) presented with increased intracranial pressure and 88% (15/17) with visual disturbances. Hormonal, mental and behavior changes were almost equally distributed in both age groups. All patients underwent craniotomy, with subtotal resection of the tumor. Three adults died of postoperative complications (10%), of whom two died of pulmonary emboli and one of cerebral hemorrhage. Of the remaining 26 patients, 13 received immediate postoperative radiotherapy to a total dose of 50.0 to 56.0 Gy, in a target volume including the sellar and parasellar region during an overall treatment period of five to six weeks. All patients were evaluable with a minimum follow-up of four years since they finished their treatment or until death. The five-year recurrence-rate in the group that did not receive postoperative radiation therapy was 45% (5/11 patients) and the five-year rate of death of disease in this group was 27% (3/11 patients). For the group that received immediate postoperative radiation therapy the five-year recurrence-rate was 11% (1/9 patients) and no death of disease was observed in this group. This difference between the two groups was not significant. The corresponding 10-year rates were 71% (5/7 patients) for recurrence and 57% (4/7 patients) for death of disease in the group without, and in the group with immediate postoperative radiation therapy the rate was 25% (2/8 patients) for recurrence and 0 for death of disease. This difference turns out to be significant. Critical analysis of the morbidity in patients surviving after treatment showed no adverse effect on the visual or endocrine status of the group that received postoperative irradiation. It is concluded that in the management of patients with craniopharyngiomas, postoperative irradiation after subtotal resection improves the prognosis of the patient and does not add to visual or endocrine morbidity.     

ANALYSIS OF 26,826 PATIENTS WITH TUMORS IN THE HEAD AND NECK

A series of 26,826 patients with head and neck tumer as confirmed by pathology from January 1970 to December 1989 are analyzed. It accounted for 39. 5% of all the tumors blopsied in the same interval. In this series, 72. 4% was malignant which accounted for 45. 77% of malignant tumors in different parts of the whole body. For benign tumors in the head and neck, the ratio of male to female was 0. 84:1, and for malignant tumors In the head and neck it was 2. 4:1. The most frequently involved site by the malignant tumors were :nasopharynx, mouth, maxillofacial regions, and neck. THe majority (62. 65%) of malignant tumors were located in the nasopharynx which accounted for 28. 68% of all malignanties of which the ratio of mate and female was 3:1, peak age was 41-50 years, 18 of themwas under 10 years of age, the youngest was 1 1/2 years andthe oldest was 84 years old. These data showed that malignant tunors in the head and neck regions, expecially those in the nasopharynx, are common in Guanxi province, Chi     

24例卵巢交界性上皮性肿瘤的临床及病理分析

目的：探讨卵巢上皮性交界性肿瘤的病理学改变、临床分期及手术范围对预后的影响、方法：分析1975年至1992年卵巢交界性上皮性肿瘤24例的临床资料、病理及随访结果。结果：24例中浆液性8例.粘液性15例,混合性1例。临床Ⅰ期14例、Ⅱ期5例、Ⅲ期5例。现22例存活（占92％）,2例死了肿瘤并发症肠梗阻。结论：提示细致的病理分析是诊断交界性上皮性肿瘤的关键预后与手术方式及化疗关系不密切而与肿瘤分期及术后有无肿瘤残存有关;对肿瘤复发的病例多次手术治疗是必要的。     

肺癌所致血小板增多及临床意义

目的探讨肺癌所致血小板增多及其与肺癌转移的关系。方法检测肺癌患者早中期和晚期两组的血小板数,并与正常人比较。结果肺癌早中期和晚期患者的血小板计数分别为(242.07±53.79)×109/L和(277.50±68.04)×109/L,均比正常人血小板计数(214.08±40.86)×109/L高,且晚期患者的血小板计数高于早中期患者。结论血小板与肺癌的发生、发展和转移有关,血小板增多可作为一个预后判断因素,抗血小板治疗是肺癌综合治疗所必须的。     

小儿睾丸肿瘤腹膜后淋巴结清扫与AFP变化

目的探讨腹膜后淋巴结清扫术以及AFP在小儿睾丸肿瘤治疗中的价值。方法43例小儿睾丸肿瘤中有27例行腹膜后淋巴结清扫术。16例AFP升高，随访32例存活29例，其中淋巴结清扫16例，未清扫13例，存活病例中术前AFP阳性8例。结果腹膜后淋巴结清扫组的存活率与未清扫组无显著差异，术前AFP阳性的存活率与阴性者亦无显著差异。结论不应将腹膜后淋巴结清扫术作为小儿睾丸肿瘤的常规治疗；术前AFP升高与预后无相关关系。     

肠道菌群在肿瘤进程中的作用及其临床研究进展

肠道菌群在调控宿主的生长、发育、营养代谢以及免疫稳态方面具有重要的作用.近年来研究发现,肿瘤患者,特别是结直肠癌患者的肠道菌群多呈现失调的状态,而肠道菌群失调能够通过影响肠道代谢、肠道稳态以及肠道免疫等方面促进或者抑制肿瘤的发生发展.目前,通过干预肠道菌群来进行肿瘤治疗的临床实践已经显示出了良好的疗效和巨大的潜能.本文主要论述肠道菌群在肿瘤发生发展进程中的作用及其机制,以及目前利用肠道菌群治疗肿瘤的相关临床研究进展.     

假基因对肿瘤生物学行为影响及机制的研究进展

假基因是一类与编码基因高度相似但不能表达功能蛋白质的细胞内非编码基因,曾一度被认为是“化石基因”。随着人们对假基因调节功能的不断认识,假基因在恶性肿瘤发生发展中的作用逐渐得到了重视。本文从假基因对恶性肿瘤细胞生物学行为的影响方面对近年来的研究进行了回顾。一般认为,假基因可以通过其转录产物影响同源或非同源的编码基因表达,并通过多种机制调节肿瘤细胞生物学行为。假基因是否有其它影响肿瘤生物学行为的机制还有待研究。