Short telomeres are frequent in hereditary breast tumors and are associated with high tumor grade

Telomere shortening is a common event involved in malignant transformation. Critically short telomeres may trigger chromosomal aberrations and produce genomic instability leading to cancer development. Therefore, telomere shortening is a frequent molecular alteration in early stages of many epithelial tumors and in breast cancer correlates with stage and prognosis. A better understanding of the involvement of short telomeres in tumors may have a significant impact on patient management and the design of more specific treatments. To understand the role of telomere length (TL) in breast cancer etiology we measured the length of individual telomere signals in single cells by using quantitative telomere in situ hybridization in paraffin-embedded tissue from hereditary and sporadic breast cancers. A total of 104 tumor tissue samples from 75 familial breast tumors (BRCA1, n = 14; BRCA2, n = 13; non-BRCA1/2, n = 48) and 29 sporadic tumors were analyzed. Assessment of telomere signal intensity allowed estimation of the mean TL and related variables, such as percentage of critically short telomeres and percentage of cells with short telomeres. These data were correlated with the immunohistochemical expression of molecular breast cancer markers. Hereditary BRCA1, BRCA2, and non-BRCA1/2 tumors were characterized by shorter TL comparing to sporadic tumors. Considering all tumors, tumor grade was a strong risk factor determining the proportion of short telomeres or short telomere cells. Moreover, some histopathological features appeared to be differentially associated to hereditary or sporadic subgroups. Short telomeres correlated with ER-negative tumors in sporadic cases but not in familial cases, whereas a high level of apoptosis was associated with shorter telomeres in hereditary BRCA1 and BRCA2 tumors. In addition, TL helped to define a subset of non-BRCA1/2 tumors with short telomeres associated with increased expression of antiapoptotic proteins. These findings highlight the potential interest of TL measurements as markers of aggressiveness in breast cancer.     

Genetic susceptibility loci of lung cancer are associated with malignant risk of pulmonary nodules and improve malignancy diagnosis based on CEA levels

Objective: The heightened prevalence of pulmonary nodules(PN) has escalated its significance as a public health concern. While the precise identification of high-risk PN carriers for malignancy remains an ongoing challenge,genetic variants hold potentials as determinants of disease susceptibility that can aid in diagnosis. Yet, current understanding of the genetic loci associated with malignant PN(MPN) risk is limited.Methods: A frequency-matched case-control study was performed, comprising 247 ...     

Molecular profiling of mouse lung tumors: association with tumor progression, lung development, and human lung adenocarcinomas

We have performed oligonucleotide array analysis on various murine lung tissues [normal lungs, lung adenomas, and lung adenocarcinomas (ACs)] using Affymetrix U74Av2 GeneChips to examine the complex genetic changes occurring during lung carcinogenesis. Analysis yielded 20 novel genes differentially expressed in both lung adenomas and ACs versus normal lungs, including the tumor suppressor APC2 and the oncogene Ros 1. In addition, 50 genes were found to be differentially expressed in lung adenomas versus lung ACs, including the differentiation factor Hox C6, the oncogene Ets 2, and the Ras nuclear transport factor, nuclear transport factor 2. To understand the potential relationship between genes expressed in murine lung tumors and its relationship to altered gene expression observed during embryogenesis and postnatal development, tissues from embryonic lungs and from lungs of mice up to 4 weeks following birth were examined using Affymetrix U74Av2 GeneChips. From this analysis, approximately 1300 genes were determined to exhibit differential expression in fetal lung versus postnatal lung. When we compared lung adenomas, lung ACs, and normal lung parenchyma, 24 developmentally regulated genes were found aberrantly expressed in lung tumors; these included the cell cycle control factor CDC5, the cellular differentiation factor TEA domain 4, and the proapoptotic factor BNIP 2. Finally, we compared the murine lung tumor gene expression data to the expression of genes in human lung cancer, in order to assess the relevance of murine lung cancer models in the study of human AC formation. When the 17 human lung ACs and six human lung large cell carcinomas were examined, it was found that 13 of the 17 human lung ACs clustered tightly together in a pattern that was different from the remaining four human lung ACs and six large cell carcinomas, which exhibited a different pattern. Interestingly, the mouse lung adenomas appeared similar to 13 clustered ACs, while mouse lung ACs appeared more similar in pattern to the group consisting of four ACs and six large-cell carcinomas (LCCs). Nevertheless, when compared with the combined human ACs, 39 genes with similar expression changes in murine lung tumors and human ACs/LCCs were identified, such as the oncogene-related BCL7B, the cell cycle regulator CDK4, and the proapoptotic Endophilin B1. Overall, we have determined, for the first time, the expression profiles during murine lung tumor progression and have established, at the molecular level, an association between murine lung tumorigenesis and lung development. We have also attempted to compare the expression profiles found in mouse lung cancers and those in human lung ACs.     

Genetic heterogeneity in lung and colorectal carcinoma as revealed by microsatellite analysis in plasma or tumor tissue DNA

BACKGROUND: Determination of tumor clonality has implications for molecular characterization and the optimal treatment of cancer. Allelotyping allows detection of the two alleles, maternal and paternal, and provides additional information regarding clonal genetic defects. The presence of allelic imbalances (AI) in tumors is a general event, but is not necessary at the same allele (alternative AI). The authors' goal was to determine whether the presence of alternative AI (AA) was a marker of heterogeneity and prognosis. METHODS: To further analyze the heterogeneity of lung tumors, tumor DNA released in the plasma was compared with primary tumor DNA from 24 lung carcinoma patients. The comparison was performed by allelotyping using 12 microsatellites targeting 9 chromosomal regions, taking in each case leukocyte DNA as reference. To extend and confirm these observations, 26 primary colorectal carcinomas with paired synchronous liver metastasis were analyzed using an enlarged panel of 33 microsatellites. RESULTS: AA were observed in 40% (20 of 50) of all patients, in 25% (6 of 24) of lung carcinoma patients but at a higher level, and in 54% (14 of 26) of colorectal carcinoma patients. They affected different chromosome localizations and each tumor stage. In both types of cancer, patients with AA had a higher AI mean frequency in their primary tumor. CONCLUSIONS: Detection of AA is an original marker of heterogeneous tumors, demonstrating that independent events occurred on specific genetic sites required for cancer progression.     

RUNX3 methylation reveals that bladder tumors are older in patients with a history of smoking

Exposure to tobacco smoke is associated with increased DNA methylation at certain genes in both lung and bladder tumors. We sought to identify interactions in bladder cancer between DNA methylation and a history of smoking, along with any possible effect of aging. We measured DNA methylation in 342 transitional cell carcinoma tumors at BCL2, PTGS2 (COX2), DAPK, CDH1 (ECAD), EDNRB, RASSF1A, RUNX3, TERT, and TIMP3. The prevalence of methylation at RUNX3, a polycomb target gene, increased as a function of age at diagnosis (P = 0.031) and a history of smoking (P = 0.015). RUNX3 methylation also preceded methylation at the other eight genes (P < 0.001). It has been proposed that DNA methylation patterns constitute a "molecular clock" and can be used to determine the "age" of normal tissues (i.e., the number of times the cells have divided). Because RUNX3 methylation increases with age, is not present in normal urothelium, and occurs early in tumorigenesis, it can be used for the first time as a molecular clock to determine the age of a bladder tumor. Doing so reveals that tumors from smokers are "older" than tumors from nonsmokers (P = 0.009) due to tumors in smokers either initiating earlier or undergoing more rapid cell divisions. Because RUNX3 methylation is acquired early on in tumorigenesis, then its detection in biopsy or urine specimens could provide a marker to screen cigarette smokers long before any symptoms of bladder cancer are present.     

Genetic alterations of the NRP/B gene are associated with human brain tumors

Nearly all brain tumors develop following the progressive accumulation of genetic alterations of oncogenes and tumor suppressor genes (such as p53 and retinoblastoma protein). Furthermore, aberrations in the nuclear matrix often contribute to genomic instabilities and the development of cancer. We have previously shown that nuclear-restricted protein/brain (NRP/B), a member of the BTB/Kelch repeat family, is a nuclear matrix protein normally expressed in neurons but not in astrocytes, and that it is an early and specific marker of neurons during the development of the central nervous system. Here, we show aberrant expression of NRP/B in human brain tissues. NRP/B is expressed in the cytoplasm of human brain tumor cells (glioblastoma, GBM) arising from astrocytes. NRP/B mutations (13 mutations in the Kelch domains, two in the intervening sequence (IVS) domain and two in the BTB domain) were detected in brain tumor cell lines (A-172, CCF-STTG1, SK-N-SH and U87-MG) and in primary human malignant GBM tissues (eight samples). More importantly, we found that NRP/B mutants, but not wild-type (wt) NRP/B, increased the activation of ERK and consequently promoted cell proliferation, attenuated caspase activation and suppressed the cellular apoptosis induced by the stressful stimulus cisplatin (10 microM). These events were observed to occur via a p53-mediated pathway. In addition, while wt NRP/B was associated with actin, mutations in the Kelch domains of NRP/B led to its reduced binding affinity to actin. Thus, alterations and gene mutations within the NRP/B gene may contribute to brain tumorigenesis by promoting cell proliferation, suppressing apoptosis and by affecting nuclear cytoskeleton dynamics.     

肺内大肿块呼吸动度的测量与分析

 目的　分析肺内肿瘤因呼吸导致运动的影响因素,寻找运动度大的肿瘤特征。方法　分别在平静吸气后屏气、平静呼气后屏气状态下接受CT扫描的肺内肿瘤患者30例,肺内可测量病灶30个。由同一位医生在两个时相的CT数据上勾画肿瘤大体肿瘤体积（GTV）,分别测量GTV中心层面前后内外界在呼吸周期中左右、前后方向的运动幅度;肿瘤最上层及最下层上下方向的运动幅度。对与运动度可能相关的临床变量和解剖学因素进行讨论。结果　肺内大肿瘤位置相对固定,肿瘤中心层面各方向动度多数在3～5 mm,只有2例患者肿瘤的各个方向运动幅度>5 mm,均位于胸腔中下部及中后部,粘连系数较低,体积较小,为上下方向运动。95 %的肺内肿瘤中心层面的运动幅度在上下方向＜3.8 mm,前后方向＜5.8 mm,左右方向＜1.1 mm。结论　呼吸导致的肺内肿瘤运动度受肿瘤位置、体积及粘连程度等因素影响,但运动幅度较小,下后带运动度最大,主要发生在上下方向。     

Ki-ras mutations are an early event and correlate with tumor stage in transplacentally-induced murine lung tumors

A previous study from this laboratory demonstrated that treatment of pregnant mice with 3-methylcholanthrene (MC) caused lung tumors in the offspring at 1 year after birth, the incidence of which correlated with fetal inducibility of Cyp1a1. Analysis by PCR amplification and allele- specific hybridization (ASO) of paraffin-embedded tumors generated from that study revealed the presence of point mutations in exon 1 of the Ki- ras gene. This work has now been expanded by PCR amplification and ASO analysis of 31 additional lesions. Point mutations were found in 37 of the 47 (79%) lesions analyzed in this and the previous study, the majority of which were G-->T transversions in the first or second base of codon 12. The mutational spectrum appeared to be dependent on the relative stage of differentiation of the lesion, as both the incidence of mutation and type of mutation produced correlated with malignant progression. Mutations occurred in 60% of the hyperplasias, 80% of the adenomas and 100% of the adenocarcinomas. In the lesions with mutations, GLY12-->CYS12 transversions occurred in 100% of the hyperplasias, 42% of the adenomas and 14% of the adenocarcinomas. The GLY12-->VAL12 transversions occurred in none of the hyperplasias, 42% of the adenomas and 57% of the adenocarcinomas. The remaining mutations, which consisted of ASP12 transitions and ARG13 transversions, occurred only in adenomas (17%) and adenocarcinomas (29%). Between this study and our previous analyses, the identity of the mutations obtained by ASO were confirmed by sequence analysis of eight of the 37 lesions that harbored mutations at the Ki-ras gene locus. There were no differences in the type or incidence of mutations relative to the metabolic phenotype or sex of the mice. These data suggest that mutational activation of the Ki-ras gene locus is an early event in transplacental lung tumorigenesis, and that the type of mutations produced by exposure to chemical carcinogens can influence the carcinogenic potential of the tumor. This may have prognostic significance in determining the malignant progression of the neoplasm.      

Progression of tumor histiotype during mouse hepatocarcinogenesis associated with the viable yellow (Avy) gene

Increasing attention has been focused recently upon those factors in carcinogenesis that are responsible for the proliferation of initiated cells and the increasingly aberrant phenotype that they progressively manifest. The agouti locus allele Avy (viable yellow) has been shown to be associated with conditions which favor promotion of cells that have been initiated by a wide variety of causes, in many organs, but has not been previously associated with tumor progression in those systems. In the current study, the presence of the Avy gene in a strain of mice not normally predisposed to hepatocarcinogenesis, C57BL/6N was, for the first time, associated not only with much earlier appearance, but with progression of the histiotype of hepatic tumors, following neonatal administration of diethylnitrosamine. At 52 weeks, 28 C57BL/6N mice demonstrated 7 mouse liver tumors 0.5 cm or greater in diameter, all of more benign histiotype, without associated metastasis. The 31 C57BL/6N-Avy demonstrated 194 mouse liver tumors at that time, 22% of which were of malignant histiotype, 19% of which were associated with metastasis. This system would appear to offer the possibility of identifying the underlying mechanisms for components of the carcinogenic process. In addition, the C57BL/6N-Avy mouse appears to offer advantages as a test animal in bioassay procedures that use the liver as a target organ. Thus, it represents a mouse with little or no spontaneous predisposition to hepatocarcinogenesis, with a predicted short lag period toward response to hepatocarcinogens.     

High cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2) contents in mouse lung tumors

Mouse lung tumorigenesis is a convenient model for examining all stages of lung adenocarcinoma (AC) progression. Because enhanced cyclooxygenase 2 (COX-2) expression has been observed in advanced human AC, we investigated the intracellular concentrations of the two cyclooxygenases, cyclooxygenase 1 (COX-1) and COX-2, at different times after carcinogen administration to A/J mice. The concentrations of both proteins were much higher in urethane-induced adenomas and carcinomas compared with control A/J mouse lung tissue (P < 0.03 and P < 0.01 in adenomas and AC, respectively, for COX-1; P < 0.003 and P < 0.004 in adenomas and AC, respectively, for COX-2). Small benign tumors that arose spontaneously in 13-month-old mice also stained for COX-1 and COX-2, showing that this elevated enzyme content does not depend on chemical induction. COX-1 and COX-2 immunostaining was observed in normal bronchiolar and alveolar epithelia, alveolar macrophages and bronchiolar smooth muscle. This is the first report of the cellular distribution of COX-1 and COX-2 in murine lungs and the first in any species to demonstrate their co-localization. COX content in isolated bronchiolar Clara cells, a putative cell of tumor origin, was equal to that found in tumors, suggesting that the high enzyme content in neoplasms is due to their proportionally high concentration of these tumor precursor cells. Different patterns of COX-1 and COX-2 expression were observed in tumors of different growth patterns; only occasional small foci stained in solid adenomas, while most cells in papillary adenomas were immunoreactive. This staining pattern was also seen in adenocarcinomas, but some of the papillary portions also included focally stained and unstained regions. The continued expression during neoplastic progression of these specialized enzymes present in normal cells of tumor origin suggests their function in maintenance of the neoplastic state.     

Tissue distribution of mouse mammary tumor virus (MMTV) antigens and new endogenous MMTV loci in Japanese laboratory mouse strains.

The distribution of mouse mammary tumor virus (MMTV) antigens was studied by the immunoperoxidase method in the II-TES and I-TES mouse strains as well as their progenitors, CS and DBA/2 strains. In the II-TES, I-TES and CS strains, and BALB/c mice foster-nursed with these strains, MMTV antigens were found not only in epithelial cells of the mammary glands but also in those of other tissues including the seminal vesicle, vas deferens, epididymis, prostate, parotid, submandibular, lacrimal, sebaceous, and urethral glands. In DBA/2 and BALB/cfDBA/2 mice, however, the MMTV antigens were found only in the mammary glands. Electron microscopic examination showed MMTV particles in these organs. When we examined the presence of Mtv-1 and 2 proviruses, which are known to be responsible for MMTV expression, in the genomes of the II-TES, I-TES, CS and DBA/2 strains by Southern blotting, Mtv-2 was not found in any of the mice and Mtv-1 was found in the II-TES and DBA/2 mice but not in the I-TES and CS mice. Instead, four new endogenous MMTV loci, which have never previously been reported in laboratory mouse strains, were detected in the genomes of the II-TES, I-TES and CS strains. One (designated Mtv-42) was common in the three strains and the other three (designated Mtv-43, 44 and 45) were common in the II-TEX and I-TES strains or the II-TES and CS strains. These results thus suggest that new endogenous MMTV loci may be responsible for MMTV expression in a variety of tissues of these three strains.     

Natural antibody in mammary tumor virus-infected mice that reacts with intracytoplasmic A particles of mouse mammary tumors.

By an indirect immunofluorescence technique with prolonged serum incubation on murine mammary tumor (MT) slices, 179 of 424 mice examined were found to possess natural serum antibody (antibodies) that reacted with intracytoplasmic A particles (iAp) of MT cells. The immunologic specificity of this antibody was supported by absorption and blocking experiments. Furthermore, a strong similarity was seen between the mouse antibody reaction on various MT and the fluorescence pattern of rabbit anti-iAp antiserum on these tumors. In female mice, incidence and geometric mean titers of the antibody in part were correlated to the spontaneous MT frequency of the mouse strains examined. Some mice of the strains XVII/Bin and CBA/BinfXVII/Bin, hitherto regarded as "free" of the mouse mammary tumor virus (MuMTV), also contained anti-iAp antibody in their sera. In contrast to MuMTV)-producing CBA/Bin micethese animals did not possess detectable spontaneous antibody reacting with MuMTV-B particles. Therefore, hypothetically, the antibody response in these mice might be induced by incomplete MuMTV expression. In the strain CBA/Bin, females 4 months old and older possessed the antibody in significantly higher geometric mean titers when compared to 4-week-old female mice. The history of lactation seemed to have no influence on the titer of antibody. In the comparatively high MT strains CBA/Bin and C3H/Bin, adult (4-month-old) females had the antibody in significantly higher levels when compared to age-matched males.     

Genetic progression and heterogeneity associated with the development of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma is a common fatal cancer, and Shanxi province, a region in north-central China, has some of the highest esophageal cancer rates in the world. Chromosomal regions with frequent allelic loss may point to major susceptibility genes that will assist us in understanding the molecular events involved in esophageal carcinogenesis and may serve as the basis for the development of markers for genetic susceptibility and screening for early detection of this cancer. This study was designed to identify events in the molecular progression of precursor and invasive lesions of squamous esophageal cancer. Twelve marker loci identified during our previous studies as having some of the highest rates of loss of heterozygosity (LOH) in invasive esophageal cancer were evaluated in laser-microdissected DNA obtained from low- and high-grade dysplastic lesions and invasive tumor foci from 10 fully embedded esophageal resection specimens. Each resection specimen contained a spectrum of disease, from epithelium that appeared histologically normal to invasive cancer, including a single dominant tumor surrounded by a region of precursor lesions (low- and high-grade dysplasia) and occasional "remote," nonadjacent precancerous foci. Using the 12 polymorphic markers, LOH was found in all of the three stages of disease. The frequency of LOH for all of the markers together increased with increasing disease severity. Among the informative low-grade dysplasia samples, LOH was detected with markers D3S1766 (3p), D4S2632 (4p), D9S910 (9q), and D13S1493 (13q), suggesting that LOH at these loci may be associated with early stages of tumor initiation and/or progression. LOH was detected among the informative high-grade (but not low-grade) dysplasia samples for the other eight markers tested, suggesting that LOH at these loci may occur later in the neoplastic process. In addition to the association between disease progression and these genetic changes, considerable genetic heterogeneity was found in each fully embedded resection specimen both between and within geographically separate neoplastic lesions.     

肺癌三维适形放疗与常规放疗剂量学优势的比较

目的:比较肺癌三维适形放射治疗与常规放射治疗时的肿瘤靶区、正常组织和器官的剂量分布优势。方法:选择三维适形放射治疗进行根治性治疗的10例肺癌,先在适形放射治疗体位下在模拟机下常规定位,标出其射野范围后进行CT模拟扫描。非小细胞肺癌在DT40Gy时行第2次CT扫描调整CTV,常规照射设野避开脊髓加量。采用三维适形治疗计划系统评价常规照射和三维适形照射对肿瘤靶区、正常组织和器官的剂量分布。结果:三维适形放射治疗比常规放射治疗,从剂量分布对肿瘤靶区有更好的适形度,95%CTV达到的平均剂量高出11·5Gy(5~20Gy),平均高出医生给予剂量CTV体积的38%(10%~59%)。在正常组织中,除健侧肺的V20和V30比常规放疗稍高外(1·1%和1·7%),脊髓的最大剂量平均低4Gy(-4~12Gy),心脏V35低24·3%(-4%~75%),双肺V20和V30分别低7%(-5%~20%)与7·4%(-6%~20%),患侧肺的V20和V30分别低13%(-7%~45%)和15%(-8%~40%)。结论:三维适形放疗治疗肺癌比常规放射治疗有一定的优势,对肿瘤靶区有更好的适形度和剂量均匀性,并且能更好的减少正常组织脊髓、心脏和肺的照射体积和剂量,特别是高剂量的照射体积。