共查询到20条相似文献,搜索用时 15 毫秒
1.
The Multivariate Prognostic Index and nuclear DNA content are independent prognostic factors in primary breast cancer patients 总被引:3,自引:0,他引:3
The predictive value of a previously described Multivariate Prognostic Index (which incorporates weighted values of the mitotic activity index, tumor size, and the axillary lymph node status), and the nuclear DNA content (DNA) was evaluated in 156 patients with primary invasive ductal breast cancer, diagnosed between 1980 and 1983. The results were analysed with respect to the occurrence of distant recurrence and survival of the patients after at least 3 yr of follow-up (range 36-73 months; median 44 months). Known prognostic factors such as lymph node status, tumor size, and the mitotic activity index correlated independently with distant recurrence. Furthermore, in respect to survival, the investigated prognostic factors (except DNA content) were significantly correlated. The results indicate that the predictive value of the Multivariate Prognostic Index (MPI) is stronger (P less than 0.001) than of the nuclear DNA content (P less than 0.005) with respect to distant recurrence. In a Cox multivariate regression analysis DNA ploidy turned out to be an independent prognostic factor once the MPI was selected. Furthermore, in Cox's analysis, DNA ploidy was the fourth selected variable after lymph node status, mitotic activity index, and tumor size in individual parameter analysis. The results of this study indicate that, with respect to breast cancer screening programs, it seems worthwhile to integrate morphometric features, the MPI, and DNA ploidy in a new prognostic model. 相似文献
2.
A B?cking R Chatelain S Biesterfeld E Noll D Biesterfeld D Wohltmann C Goecke 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1989,11(2):73-80
The prognostic significance of the "DNA malignancy grade" (DNA-MG) was tested in a series of 104 breast cancer patients in comparison with TNM staging, histomorphologic grading according to Bloom and Richardson, mean nuclear area (MNA) and DNA-histogram classification according to Auer. The reproducibility and representativity of the grading systems were investigated, and their results in primary tumors and lymph node metastases were compared. The scalar DNA-MG was assessed on monolayer smears prepared from paraffin-embedded tissues; the smears were automatically Feulgen stained and used for rapid interactive DNA cytometric evaluation by an automated microscope and a TV image-analysis system. TNM staging showed the highest correlation with survival, followed by histomorphologic grading and DNA-MG; MNA and the DNA-histogram classification failed to give statistically significant prognostic information. Both histomorphologic grading and DNA-MG were identified as parameters adding independent prognostic information to the TNM staging. However, only DNA-MG demonstrated an acceptable reliability, with small 95% ranges between repeated measurements within the primary tumor (+/- 0.3 DNA-MG) and a strong correlation between the results in the primary tumor and its lymph node metastases. These findings show that the DNA-MG is a valid and reliable prognostic index that adds significant prognostic information to TNM staging. 相似文献
3.
Martín R Sneige N Vásquez M Aragón-Flores M Martín G Marrón C Santamaría L 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1999,21(3):185-193
OBJECTIVE: To estimate cytologic volume-weighted mean nuclear volume and correlate it with other prognostic factors, such as tumor diameter and cytologic grading in relation to nodal infiltration. STUDY DESIGN: The relationships between nodal status and nuclear VV, tumor diameter and cytologic grading, according to the modified Black nuclear grading system, were analyzed on fine needle aspirates of 49 cases of breast cancer by univariate and multivariate logistic regression. RESULTS: Volume-weighted mean nuclear volume (nuclear VV) estimated on fine needle aspiration smears showed a significant correlation with grade of tumor differentiation. CONCLUSION: Stereologic evaluation of nuclear size by nuclear VV is an objective method for the cytologic grading of ductal carcinoma of the breast and has independent prognostic value in relation to nodal status higher than those of tumor diameter and cytologic grade. 相似文献
4.
Rodríguez J Vázquez J Corte MD Lamelas M Bongera M Corte MG Alvarez A Allende M Gonzalez L Sánchez M Vijande M Garcia Muñiz J Vizoso F 《The International journal of biological markers》2005,20(2):103-111
BACKGROUND: Cathepsin D is the proteolytic enzyme most frequently implicated as a prognostic factor in primary breast cancer. In the present study we evaluated by means of an immunoradiometric assay the tumor content of this protease in primary breast cancer, its relationship with tumor-related clinical and pathological parameters, and its prognostic significance in a large series of breast cancer patients. METHOD: The study comprised 1033 women with histologically established invasive breast cancer. Cathepsin D was measured in cytosol samples by means of an immunoradiometric assay to determine the total amount of cathepsin D (52 kDa, 48 kDa and 34 kDa). Evaluation of relapse-free survival and cause-specific survival was performed in the group of 1003 patients without evidence of metastasis at the time of initial diagnosis. The median follow-up of the patients who were free of recurrence was 54 months. RESULTS: Cathepsin D levels showed a wide range among the studied tumors (n = 1033; median (range) 41 (0.9-2504) pmol/mg protein). Statistical analysis showed that the median cathepsin D levels were considerably higher in large tumors (T2-4) than in smaller ones (T1) (p = 0.017), as well as in node-positive than in node-negative tumors (p = 0.004). Cathepsin D levels were also higher in ductal tumors than in the other histological types (p = 0.001), as well as in moderately or poorly differentiated tumors (p < 0.001). Likewise, the median value of the protease was significantly higher in ER or PgR-positive tumors than in hormone receptor-negative ones (p = 0.011 and p = 0.004, respectively), as well as in aneuploid tumors than in diploid tumors (p = 0.029). Multivariate analysis demonstrated that elevated cathepsin D levels (> 59 pmol/mg protein) were notably associated with a shorter cause-specific survival in the whole group of patients with breast cancer, as well as in the subgroup of node-positive patients (p < 0.05). CONCLUSIONS: This study suggests that elevated intratumoral cathepsin D levels may identify a subset of node-positive breast cancer patients showing a high probability of earlier death. 相似文献
5.
K Nishimiya G U Auer K Erhardt L G Wiman H Kato Y Hayata 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1985,7(2):153-158
The nuclear DNA content in morphologically identified tumor cells was analyzed in 4-micron histologic sections from 58 patients with lung carcinoma who survived for at least five years. Thirty-three of the carcinomas were invasive squamous bronchial carcinomas and 25 were pulmonary adenocarcinomas. In all squamous carcinomas, the majority of tumor cells were found to exhibit DNA values exceeding the normal tetraploid and/or diploid region. In contrast, some of the pulmonary adenocarcinomas were found to be composed of a majority of tumor cells with DNA values in the normal diploid region. The results indicate that invasive squamous bronchial carcinomas, in general, are tumors with aneuploid DNA patterns indicative of a high malignant potential and that malignancy grading based on DNA measurements does not add any significant prognostic information to that obtained by morphologic diagnosis. 相似文献
6.
Feulgen-stained tissue sections of 187 invasive ductal carcinomas (94 with lymph node metastases; mean follow-up: 44 months) were studied using computer assisted image cytometry. Based on survival time, the prognostic significance of nuclear image analysis was compared with the results using conventional histopathological grading according to Bloom and Richardson, as well as with image cytometric DNA measurements. The histopathological grading has the disadvantage of poor interobserver reproducibility (71.1%). Despite statistically significant differences between the actuarial survival curves of grade 1 and grade 3 patients, the prognostic significance of the conventional grading method for individual patients seems to be low and the number of grade 2 cases (42.8%) is large. The quantitative morphological method for analyzing nuclear images gives more reproducible results. Compared to histopathological grading, the predictive values for good or poor prognosis are clearly higher and the number of cases with uncertain prognosis is significantly smaller (20.9%). DNA ploidy measurements also make it possible to distinguish statistically significant differences between favorable and unfavorable prognoses with respect to over-all survival time. However, the classification accuracy based on the best single parameter (DNA-histogram type according to Auer) is 70.2% compared with 78.9% for nuclear image analysis. 相似文献
7.
Kronqvist P Kuopio T Collan Y 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2003,25(1):47-52
OBJECTIVE: To quantify the histologic changes caused by freezing during tissue processing and their influence on histologic malignancy grading as a prognostic factor in invasive ductal breast cancer. STUDY DESIGN: We studied frozen and nonfrozen formalin-fixed, paraffin-embedded samples of 18 cases of invasive ductal breast cancer. Features associated with histologic malignancy grading of breast cancer--i.e., nuclear pleomorphism, mitotic index and tubular differentiation--were assessed by quantitative morphometric methods. RESULTS: In our material, frozen samples consistently had a smaller mean nuclear profile area than nonfrozen samples (mean difference, 32%). Frozen nuclei were also clearly less symmetric and uniform in shape than non-frozen nuclei. Moreover, frozen samples had consistently higher mitotic indices than nonfrozen samples (mean difference, 66%, with the standardized mitotic index). Tubular differentiation, as expressed in fraction of fields with tubular differentiation, increased by 16% as a result of sample freezing. CONCLUSION: According to our results of morphometric measurement in invasive ductal breast cancer, great caution should be exercised when prognostic conclusions are based on frozen tissue samples. 相似文献
8.
Neuburger M Xia Y Herget GW Huang Y Adler CP 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1999,21(6):461-467
OBJECTIVE: To investigate the prognostic significance of DNA image cytophotometric data. STUDY DESIGN: Twenty-six osteosarcomas in patients without lung metastases were investigated for several cytophotometric data. In 24 cases, these data were correlated with the clinical course of the patients to assess the prognostic value of nuclear DNA content in osteosarcomas. RESULTS: Of all osteosarcomas, 96% showed aneuploid DNA content. Patients with tumors having a 2c deviation index (2cDI) of 12.00, DNA malignancy grade (DNA-MG) of 2.0, a mean DNA content (MDC) of 4.95 c, DNA index (DI) of 1.75 or mean nuclear area (MNA) of 130 microns 2 had a significantly lower overall survival rate as compared to those with lower values (P < .05). CONCLUSION: Image cytophotometric features, such as 2cDI, DNA-MG, MDC, DI and MNA, are of prognostic value in patients with osteosarcoma and free of lung metastases. 相似文献
9.
M L Kelsten M S Berger H C Maguire D A Chianese M E Hellman D B Weiner M I Greene 《Cytometry》1990,11(4):522-532
Breast cancer is a leading cause of cancer death among women. Factors useful for determining the prognosis of breast cancer include axillary lymph node involvement, tumor size, hormonal receptor status, nuclear grade, and relative DNA content. The c-erbB-2 protooncogene is amplified in 10-40% of primary breast tumors, as well as in breast cancer cell lines; where it is amplified there is increased expression of its product. We have investigated the DNA content and c-erbB-1 protein expression in tumor cell lines and in breast cancer patient specimens by multiparameter flow cytometry. The study was enabled by the discovery that both cellular integrity and c-erbB-2 antigen reactivity were preserved in cells and tissues following fixation in 70% ethanol. We demonstrate that flow cytometric analysis of c-erbB-2 expression in populations of ethanol-fixed tumor cells is a reliable and sensitive quantitative method that correlates well with previously documented semiquantitative techniques. This is a feasible method for analyzing archived clinical samples, and further allows correlations between c-erbB-2 levels and other cellular parameters. Additionally, this method detects abnormal populations not identified by DNA content analysis alone. Further studies utilizing this approach are necessary to evaluate the prognostic value of this oncoprotein in human breast cancer. 相似文献
10.
Prognostic significance of DNA ploidy determined by high-resolution flow cytometry in breast carcinoma 总被引:3,自引:0,他引:3
Bracko M Us-Krasovec M Cufer T Lamovec J Zidar A Goehde W 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2001,23(1):56-66
OBJECTIVE: To assess the prognostic value of DNA ploidy in breast carcinoma and its relation to other established prognostic factors. STUDY DESIGN: We evaluated DNA ploidy in 303 breast carcinoma patients with a median follow-up of 63 months. Flow cytometry was performed on frozen tumor material, yielding histograms with narrow peaks (median coefficient of variation of 2.08). DNA ploidy pattern was classified as either diploid versus nondiploid, euploid (diploid and tetraploid) versus aneuploid or diploid/near-diploid (DNA index < 1.2) versus other, and correlated with relapse-free (RFS) and cancer-specific survival (CSS) along with tumor size, histologic grade and type, axillary lymph node involvement, menopausal and steroid receptor status, age and type of treatment. RESULTS: Seventy-one percent of tumors were DNA nondiploid (14% tetraploid and 57% aneuploid). There was a strong association between DNA ploidy and histologic grade. Histologic grade, lymph node status, tumor size and DNA ploidy (regardless of the classification used) were all significantly associated with RFS and CSS in multivariate analysis. CONCLUSION: These results suggest that DNA ploidy, at least when determined from frozen tumor tissue, is an independent prognostic factor in breast carcinoma; however, its prognostic power seems to be inferior to that of histologic grade, with which it strongly correlates. 相似文献
11.
The nuclear DNA content of diploid and triploid Poeciliopsis and other poeciliid fishes with reference to the evolution of unisexual forms 总被引:1,自引:0,他引:1
Michael C. Cimino 《Chromosoma》1974,47(3):297-307
The nuclear DNA content of all diploid poeciliid fishes known to date ranges from 1.30 to 1.92 pg, and is thus lower than the median amount for fishes in general, and teleost fishes in particular (2.0 pg). As is expected, triploid forms of Poecilia and Poeciliopsis have half again as much nuclear DNA as diploid forms. Unisexual forms of the two genera tend to have slightly less nuclear DNA than the amount expected if compared with their gonochoristic progenitors. 相似文献
12.
P Troncoso H E Dytch M Bibbo G L Wied P J Dawson 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1989,11(3):166-172
The nuclear DNA content and other karyometric parameters were evaluated in a histologically homogeneous group of invasive ductal carcinomas of the breast from 13 patients who survived 25 years after radical mastectomy and from 13 controls matched for histologic tumor grade, lymph node status, tumor size and patient age. The nuclear DNA content and other morphometric features were evaluated by image analysis (using a modified TICAS system) on 12-microns-thick, Feulgen-stained sections. The DNA content of the tumors of both the long-term survivors and the controls varied from the diploid range to highly aneuploid (with a large proportion of the cells having a DNA content above 5N). Overall, the tumors of the controls exhibited a higher ploidy, a greater deviation from the diploid range and a greater variation of nuclear size than did the tumors of the long-term survivors. These results suggest that these measurements may be helpful in yielding prognostic information among sets of histologically identical breast tumors of similar pathologic stage. 相似文献
13.
14.
Essential roles for GPI-anchored proteins in African trypanosomes revealed using mutants deficient in GPI8
下载免费PDF全文
![点击此处可从《Molecular biology of the cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lillico S Field MC Blundell P Coombs GH Mottram JC 《Molecular biology of the cell》2003,14(3):1182-1194
The survival of Trypanosoma brucei, the causative agent of Sleeping Sickness and Nagana, is facilitated by the expression of a dense surface coat of glycosylphosphatidylinositol (GPI)-anchored proteins in both its mammalian and tsetse fly hosts. We have characterized T. brucei GPI8, the gene encoding the catalytic subunit of the GPI:protein transamidase complex that adds preformed GPI anchors onto nascent polypeptides. Deletion of GPI8 (to give Deltagpi8) resulted in the absence of GPI-anchored proteins from the cell surface of procyclic form trypanosomes and accumulation of a pool of non-protein-linked GPI molecules, some of which are surface located. Procyclic Deltagpi8, while viable in culture, were unable to establish infections in the tsetse midgut, confirming that GPI-anchored proteins are essential for insect-parasite interactions. Applying specific inducible GPI8 RNAi with bloodstream form parasites resulted in accumulation of unanchored variant surface glycoprotein and cell death with a defined multinuclear, multikinetoplast, and multiflagellar phenotype indicative of a block in cytokinesis. These data show that GPI-anchored proteins are essential for the viability of bloodstream form trypanosomes even in the absence of immune challenge and imply that GPI8 is important for proper cell cycle progression. 相似文献
15.
Giani C Campani D Rasmussen A Fierabracci P Miccoli P Bevilacqua G Pinchera A Cullen KJ 《The International journal of biological markers》2002,17(2):90-95
Recent in situ hybridization experiments have shown a high content of IGF-II mRNA in breast cancer stroma. The aim of this study was to examine the relationship between IGF-II protein expression and several prognostic parameters in 75 infiltrating ductal carcinomas (IDC) of the breast. Tissue sections were evaluated for proliferative activity, IGF-II protein, ER, PgR, p53, and p21 expression using immunohistochemical procedures. The degree of stromal proliferation was assessed. Menopausal status, axillary lymph node involvement and nuclear grade were known. Thirty-five patients (44.3%) were premenopausal and 47 (62.6%) had lymph node metastases. Marked stromal proliferation was found in 34 (45.3%) specimens and high nuclear grade in 20 (26.5%). Eighteen tumors (24%) showed no IGF-II immunostaining. In the positive cases, IGF-II was detected both in the tumor stroma and in the cytoplasm of epithelial cancer cells: a high IGF-II content was found in 12 specimens (16.0%), a low content in 14 (18.7%) and a moderate content in 31 (41.3%). Twenty-four tumors (32.0%) showed high proliferative activity. Both ER and PgR were expressed in the nucleus of cancer cells: 49 tumors (65.3%) were ER positive (ER+) and 34 (45.3%) PgR positive (PgR+). p21 protein was detected in 37 tumors (49.6%) and p53 in 12 (16%). IGF-II protein was not correlated with menopausal status, lymph node metastases, nuclear grade, proliferative activity, ER or p53. In contrast, IGF-II correlated strongly with stromal proliferation (p=0.008), PgR (p=0.03) and p21 (p=0.01). This study demonstrates that in IDC of the breast IGF-II protein is expressed in the epithelium and stroma of the majority of tumors and is correlated with stromal amount, PgR and p21 expression. These preliminary results indicate that IGF-II expression in breast cancer is connected with two important regulators of breast cancer growth and differentiation. 相似文献
16.
J Gaub 《Histochemistry》1976,49(2):113-121
From rats fed ad libitum and kept under a 12 + 12 h light/dark regimen, the DNA dependent RNA polymerase activity of liver cell nuclei was determined avery four hours. From identical rats, nuclear non-histone protein and DNA, and cytoplasmic protein was determined by Feulgen-Naphthol Yellow S cytophotometry of isolated liver cells. The minimum: maximum ratio of the RNA polymerase activity is 0.77; the min:max ratio of nuclear non-histone protein is 0.84. These two parameters have identical time courses with a gradual decline during the light period and a sharp rise after the onset of the dark period. The variations in nuclear DNA content, estimated as the amount of Feulgen stain bound, closely parallel those of the RNA polymerase activity and nuclear non-histone protein content (min:max = 0.96). The amount of cytoplasmic protein per cell also varies throughout the day, but its time curve lags behind those of nuclear non-histone content and RNA polymerase activity. These results are consistent with the concept of nuclear non-histone proteins as de-repressors of the DNA template in differentiated, non-proliferating cells, and support the validity of using Feulgen-Naphthol Yellow S cytophotometry of nuclear non-histone proteins as an estimate of gene expression in such cells. 相似文献
17.
J. Gaub 《Histochemistry and cell biology》1976,49(2):113-121
Summary From rats fed ad libitum and kept under a 12+12 h light/dark regimen, the DNA dependent RNA polymerase activity of liver cell nuclei was determined every four hours. From identical rats, nuclear non-histone protein and DNA, and cytoplasmic protein was determined by Feulgen-Naphtol Yellow S cytophotometry of isolated liver cells. The minimum: maximum ratio of the RNA polymerase activity is 0.77; the min:max ratio of nuclear non-histone protein is 0.84. These two parameters have identical time courses with a gradual decline during the light period and a sharp rise after the onset of the dark period. The variations in nuclear DNA content, estimated as the amount of Feulgen stain bound, closely parallel those of the RNA polymerase activity and nuclear non-histone protein content (min:max=0.96). The amount of cytoplasmic protein per cell also varies throughout the day, but its time curve lags behind those of nuclear nonhistone content and RNA polymerase activity. These results are consistent with the concept of nuclear non-histone proteins as de-repressors of the DNA template in differentiated, non-proliferating cells, and support the validity of using Feulgen-Naphthol Yellow S cytophotometry of nuclear non-histone proteins as an estimate of gene expression in such cells. 相似文献
18.
Nuclear protein and DNA content of HeLa cells was determined as a function of time following hyperthermia by staining isolated nuclei with two fluorescent dyes: fluorescein isothiocyanate (FITC) for protein content and propidium iodide (PI) for DNA content. Bivariate FITC and PI histograms were obtained by flow cytometry. Univariate flow cytometric analysis was shown to be inadequate for this study, because some of the nuclear protein changes were due to cell cycle redistribution. Posthyperthermia cell kinetics could be divided into two distinct phases: an early phase characterized by the removal of heat-induced excess nuclear proteins with little or no cell progression through the cell cycle; and a late phase characterized by a redistribution of cells in the cell cycle resulting in an accumulation of cells in G2. The duration of these phases was dependent upon the hyperthermia dose. In the early phase, the rate of removal of excess nuclear protein was found to vary with heating time and temperature for time-temperature combinations which resulted in the same amount of excess nuclear protein. In the late phase, the cells blocked in G2 did not reduce their nuclear protein levels back to control values. 相似文献
19.
5-Bromodeoxyuridine-dependent increase in sister chromatid exchange formation in Bloom's syndrome is associated with reduction in topoisomerase II activity 总被引:11,自引:0,他引:11
Bloom's syndrome is characterized by a high sister chromatid exchange (SCE) frequency, the basis for which is not yet understood. Immunofluorescent detection of SCE formation in dermal fibroblasts was employed over a wide range of 5-bromodeoxyuridine (BrdU) substitution into template DNA to show that this SCE elevation reflects both an increased baseline SCE frequency and an exaggerated increment in SCE formation as BrdU substitution increases. The impact of BrdU on SCE formation in Bloom's syndrome is paralleled by its ability to reduce the activity in nuclear extracts of topoisomerase II, an enzyme important for DNA replication and interchange. The extractable topoisomerase II activity of Bloom's syndrome fibroblasts, as measured by unknotting of page P4 DNA, is much more strongly inhibited by cell growth in medium containing BrdU than is that of normal fibroblasts. The results are consistent with the hypothesis that much of the BrdU-dependent component of SCE formation in Bloom's syndrome may be mediated by an effect of BrdU substitution of template DNA on topoisomerase II activity. 相似文献
20.
Phosphorylation of BLM, dissociation from topoisomerase IIIalpha, and colocalization with gamma-H2AX after topoisomerase I-induced replication damage 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Molecular and cellular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rao VA Fan AM Meng L Doe CF North PS Hickson ID Pommier Y 《Molecular and cellular biology》2005,25(20):8925-8937
Topoisomerase I-associated DNA single-strand breaks selectively trapped by camptothecins are lethal after being converted to double-strand breaks by replication fork collisions. BLM (Bloom's syndrome protein), a RecQ DNA helicase, and topoisomerase IIIalpha (Top3alpha) appear essential for the resolution of stalled replication forks (Holliday junctions). We investigated the involvement of BLM in the signaling response to Top1-mediated replication DNA damage. In BLM-complemented cells, BLM colocalized with promyelocytic leukemia protein (PML) nuclear bodies and Top3alpha. Fibroblasts without BLM showed an increased sensitivity to camptothecin, enhanced formation of Top1-DNA complexes, and delayed histone H2AX phosphorylation (gamma-H2AX). Camptothecin also induced nuclear relocalization of BLM, Top3alpha, and PML protein and replication-dependent phosphorylation of BLM on threonine 99 (T99p-BLM). T99p-BLM was also observed following replication stress induced by hydroxyurea. Ataxia telangiectasia mutated (ATM) protein and AT- and Rad9-related protein kinases, but not DNA-dependent protein kinase, appeared to play a redundant role in phosphorylating BLM. Following camptothecin treatment, T99p-BLM colocalized with gamma-H2AX but not with Top3alpha or PML. Thus, BLM appears to dissociate from Top3alpha and PML following its phosphorylation and facilitates H2AX phosphorylation in response to replication double-strand breaks induced by Top1. A defect in gamma-H2AX signaling in response to unrepaired replication-mediated double-strand breaks might, at least in part, explain the camptothecin-sensitivity of BLM-deficient cells. 相似文献