Clonogenic survival and cytokinesis-blocked binucleation of skin fibroblasts and normal tissue complications in soft tissue sarcoma patients treated with preoperative radiotherapy.

BACKGROUND AND PURPOSE:To evaluate the clonogenic and cytokinesis-blocked assays in skin fibroblast cultures for their utility as tools for predicting normal tissue responses in soft tissue sarcoma (STS) patients treated with preoperative radiotherapy. PATIENTS AND METHODS:Dermal fibroblast strains were established from skin biopsies of 26 STS patients who received preoperative radiotherapy. Cultures were subjected to the colony forming and cytokinesis-blocked assays after low (approximately 0.02 Gy/min) dose-rate 60Co -irradiation. Fibroblast radiosensitivity was expressed as the dose for 1% clonogenic survival, D0.01, based on colonies/clusters with >or=10 cells. Fibroblast proliferative capability was represented by binucleation index (BNI) and genomic damage was expressed in terms of micronucleus frequency. Wound healing complications (WHC) and subcutaneous fibrosis were the clinical endpoints examined. The ability of each in vitro parameter to detect patients at high risk of a given normal tissue complication was assessed using receiver operating characteristic (ROC) analysis. RESULTS:While fibroblasts from patients without WHC were marginally more radiosensitive than fibroblasts from patients with WHC (P=0.08), the reduction in BNI following a dose of 2.4 Gy was significantly higher in strains from patients without WHC compared to those from patients with WHC (P=0.01). The area under the ROC curve (c-index) is indicative of the power of discrimination of D0.01 and BNI for WHC, and was found to be 0.68 and 0.79, respectively. Subcutaneous fibrosis was not associated with D0.01 (rs=0.09, P=0.66) and the percent reduction in BNI after 2.4 Gy (rs=-0.19, P=0.36). Micronucleus frequency did not reflect differences in normal tissue responses. CONCLUSION:These data suggest that it is the ability of fibroblasts to undergo one-three divisions in vitro following radiation treatment that may reflect the development of wound healing morbidity or subcutaneous fibrosis in this population of patients.     

Studies of the in vivo radiosensitivity of human skin fibroblasts.

BACKGROUND AND PURPOSE: To examine the radiosensitivity of skin cells obtained directly from the irradiated skin of patients undergoing fractionated radiation treatment prior to surgery for treatment of soft tissue sarcoma (STS) and to determine if there was a relationship with the development of wound healing complications associated with the surgery post-radiotherapy. METHODS: Micronucleus (MN) formation was measured in cells (primarily dermal fibroblasts) obtained from human skin at their first division after being removed from STS patients during post-radiotherapy surgery (2-9 weeks after the end of the radiotherapy). At the time of radiotherapy (planned tumor dose - 50Gy in 25 daily fractions) measurements were made of surface skin dose at predetermined marked sites. Skin from these sites was obtained at surgery and cell suspensions were prepared directly for the cytokinesis-blocked MN assay. Cultured strains of the fibroblasts were also established from skin nominally outside the edge of the radiation beam and DNA damage (MN formation) was examined following irradiation in vitro for comparison with the results from the in situ irradiations. RESULTS: Extensive DNA damage (MN) was detectable in fibroblasts from human skin at extended periods after irradiation (2-9 weeks after the end of the 5-week fractionated radiotherapy). Analysis of skin receiving a range of doses demonstrated that the level of damage observed was dose dependent. There was no clear correlation between the level of damage observed after irradiation in situ and irradiation of cell strains in culture. Similarly, there was no correlation between the extent of MN formation following in situ irradiation and the propensity for the patient to develop wound healing complications post-surgery. CONCLUSIONS: Despite the presence of DNA damage in dermal fibroblasts weeks after the end of the radiation treatment, there was no relationship between this damage and wound healing complications following surgery post-irradiation. These results suggest that factors other than the radiosensitivity of the skin fibroblasts likely also play a role in wound healing in deep wound sites associated with surgery for STS following radiation therapy.     

Intrinsic radiosensitivity of normal human fibroblasts and lymphocytes after high- and low-dose-rate irradiation.

The existence of heritable radiosensitivity syndromes and clinical observations in radiotherapy patients suggests that human cellular radiosensitivity differs among individuals. We report here an in vitro study of radiosensitivity in 30 fibroblast and 29 lymphocyte cultures obtained from cancer patients and controls. In 25 cases, both fibroblasts and lymphocytes were obtained from the same donors. Fibroblasts were cultured from skin biopsy samples, and peripheral T-cell lymphocytes were cultured from blood. Clonogenic survival assays were performed by using high- and low-dose-rate irradiation; lymphocytes were in G0 phase and fibroblasts in confluent plateau phase. Various end points were calculated and compared (i.e., surviving fraction at 2 Gy, initial slope of the survival curve, and doses resulting in 10 and 1% survival, respectively). Depending on the end point, the coefficient of variation of the survival parameters ranged from 31 to 68% for lymphocytes and 21 to 41% for fibroblasts following high-dose-rate irradiation. Similar ranges were obtained after low-dose-rate irradiation. Variance analysis performed on replicate assays in cultures derived from the same patient showed that variation due to technical or sampling errors was significantly lower than variation between individuals (P = 0.00034 and 0.014 for fibroblasts and lymphocytes, respectively). No correlation was observed between the radiosensitivity of lymphocyte and fibroblast cultures derived from the same donors. We conclude that there is significant variation in normal cell radiosensitivity among individuals. On the other hand, comparisons of lymphocyte and fibroblast radiosensitivities suggest that tissue-specific characteristics, such as differentiation status, may variably modulate radiosensitivity.     

Correlation between normal tissue complications and in vitro radiosensitivity of skin fibroblasts derived from radiotherapy patients treated for variety of tumors

PURPOSE: To assess the relationship between fibroblast intrinsic radiosensitivity in vitro and late reactions of normal tissues in patients treated by definitive radiotherapy for variety of tumors. PATIENTS AND METHODS: Ten patients were selected for this study. They were treated by radical radiotherapy for variety of tumors, including non-Hodgkin's lymphoma, prostate, glottic larynx, anal canal, cervix, bladder, thyroid gland, and tonsil pillar. Five patients did not develop any significant late reactions (normally sensitive group, NS). The other five developed late complications in different normal tissues and organs that proved to be fatal in one patient (clinically hyper-sensitive group, HS). Fibroblast cultures were established from punch skin biopsy and radiosensitivity in vitro was measured. The survival fraction at 2 Gy (SF2) was calculated and compared between the two groups. RESULTS: SF2 ranged between 0.10 and 0.38 with a mean of 0.24. The mean SF2 for each of the NS and the HS groups were 0.31 and 0.17, respectively. The non-parametric rank test of Mann-Whitney shows that the difference between the two groups is statistically significant (p = 0.01). CONCLUSION: This study indicates that the in vitro radiosensitivity of skin fibroblasts is correlated with late complications in different organs and normal tissues following radiotherapy for variety of tumors. It also lends support to the existence of a common genetic component determining the radiosensitivity of cells targeted by the late effects of ionizing radiation.     

Cellular radiosensitivity and complication risk after curative radiotherapy.

PURPOSE: To test for an association between in vitro fibroblast radiosensitivity and complication risk in a case-control study of breast cancer patients treated under standard conditions in a clinical trial of radiotherapy dose fractionation. PATIENTS AND METHODS: A cohort of patients participating in a randomised clinical trial of radiotherapy dose fractionation was selected on the basis of treatment-induced changes in the breast several years later. Thirty-nine cases with marked normal tissue changes were matched on several variables with 65 controls with no changes attributable to radiotherapy. Dermal fibroblast strains were established from duplicate skin biopsies, and clonogenic cell survival assays performed in triplicate after both high ( approximately 1.6 Gy/min) and low ( approximately 1 cGy/min) dose-rate irradiation. Laboratory studies were blind to patient identity, treatment outcome and radiotherapy schedule. RESULTS: Analysis of 1128 clonogenic survival curves confirmed significant inter-patient variation in fibroblast radiosensitivity as measured by clonogenic survival. However, no association between fibroblast radiosensitivity and the development of late radiotherapy normal tissue effects was detected. CONCLUSIONS: Inter-individual variation in cellular radiosensitivity may not be the main determinant of complication risk in patients undergoing radiotherapy for breast cancer. Other biological and technical factors may be more important in explaining the marked inter-patient differences in normal tissue damage evident several years after curative radiotherapy.     

Plasminogen activator inhibitor-I-related regulation of procollagen I (alpha1 and alpha2) by antitransforming growth factor-beta1 treatment during radiation-impaired wound healing

PURPOSE: Plasminogen activator inhibitor (PAI)-1 mediates transforming growth factor-beta1 (TGF-beta1)-related signaling by stimulating collagen Type I synthesis in radiation-impaired wound healing. The regulation of alpha(I)-procollagen is contradictory in fibroblasts of different fibrotic lesions. It is not known whether anti-TGF-beta1 treatment specifically inhibits alpha(I)-procollagen synthesis. We used an experimental wound healing study to address anti-TGF-beta1-associated influence on alpha(I)-procollagen synthesis. METHODS AND MATERIALS: A free flap was transplanted into the preirradiated (40 Gy) or nonirradiated neck region of Wistar rats: Group 1 (n = 8) surgery alone; Group 2 (n = 14) irradiation and surgery; Group 3 (n = 8) irradiation and surgery and anti-TGF-beta1 treatment. On the 14th postoperative day, skin samples were processed for fibroblast culture, in situ hybridization for TGF-beta1, immunohistochemistry, and immunoblotting for PAI-1, alpha1/alpha2(I)-procollagen. RESULTS: Anti-TGF-beta1 significantly reduced TGF-beta1 mRNA (p < 0.05) and PAI-1 expression (p < 0.05). Anti-TGF-beta1 treatment in vivo significantly reduced alpha1(I)-procollagen protein (p < 0.05) and the number of expressing cells (p < 0.05) in contrast to significantly increased (p < 0.05) alpha2(I)-procollagen expression. CONCLUSION: These results emphasize anti-TGF-beta1 treatment to reduce radiation-induced fibrosis by decreasing alpha1(I)-procollagen synthesis in vivo. alpha1(I)-procollagen and alpha2(I)-procollagen might be differentially regulated by anti-TGF-beta1 treatment. Increased TGF-beta signaling in irradiated skin fibroblasts seemed to be reversible, as shown by a reduction in PAI-1 expression after anti-TGF-beta1 treatment.     

In vitro radiosensitivity of skin fibroblasts can identify a group of patients with complications in various health tissues after radiotherapy]

PURPOSE: A retrospective study of the in vitro radiosensitivity of skin fibroblasts derived from two groups of patients treated by definitive radiotherapy for a variety of tumors who either displayed or did not display severe complications. PATIENTS AND METHODS: Seven radiotherapy patients were selected: three were treated for head and neck, prostate and non-Hodgkin lymphoma tumors, and did not develop any significant complications (control group); four patients were treated for bladder, thyroid, head and neck and anal canal tumors and developed serious acute and especially late reactions (hypersensitive group). Primary cell cultures of skin fibroblasts were established and their radiosensitivity studied by the clonogenic assay after exposing to single radiation doses ranging between 1 and 8 Gy. RESULTS: The survival fraction at 2 Gy (SF2) ranged from 0.27 to 0.38, with a mean of 0.33 for the control group, and from 0.10 to 0.20 with a mean of 0.17 for the hypersensitive group. The Mann-Whitney non-parametric test showed that the difference between the two means was statistically significant (p = 0.03). CONCLUSION: The data are in favor of a correlation between the radiosensitivity of patients' fibroblasts and the reactions of different normal tissues to radiotherapy. This association supports the use of the clonogenic survival, or a surrogate test, as a predictive assay. The multiplicity of normal tissues and organs implicated in this association suggests the existence of genetic factors that determine, at least in part, the radiosensitivity of target cells involved in the expression of normal tissues complications following radiotherapy.     

Fractionated irradiation of five human lung cancer cell lines and prediction of survival according to a radiobiology model

BACKGROUND: This study evaluates a predictive radiobiology model by measurements of surviving fraction (SF) by the clonogenic assay or the extrapolation method and the proliferation rate in vitro. It is hypothesized that incorporating proliferation to intrinsic radiosensitivity, measured by SF, to predict radiation responsiveness after fractionated irradiation adds to the model's accuracy. Materials and Methods. Five lung cancer cell lines with known SF after 1 Gy (SF1), and also SF2 and SF5, were irradiated with three different fractionation regimes; 10 × 1 Gy, 5 × 2 Gy or 2 × 5 Gy during the same total time to achieve empirical SF. In addition, the SF1, SF2 and SF5 after fractionated irradiation was calculated for each cell line based on the already known single fraction SF and with or without a proliferation factor. The results were compared to the empirical data. Results and Discussion: By using the clonogenic assay to measure radiosensitivity, prediction of radiosensitivity was improved after fractionated radiotherapy when proliferation was used in the radiobiology model. However, this was not the case in the cell lines where the extrapolation method was used to calculate SF. Thus, a radiobiology model including intrinsic radiosensitivity, measured by the clonogenic assay, as well as proliferation, is better at predicting survival after fractionated radiotherapy, compared to the use of intrinsic radiosensitivity alone.     

Enhanced in vitro radiosensitivity of skin fibroblasts in two patients developing brain necrosis following AVM radiosurgery: a new risk factor with potential for a predictive assay

PURPOSE: Radiosurgery is an effective treatment for arteriovenous malformations (AVM) with a low risk of developing brain necrosis. Models have been developed to predict the risk of complications. We postulated that genetic differences in radiosensitivity may also be a risk factor. METHODS AND MATERIALS: Fibroblast cultures were established from skin biopsies in two AVM patients developing radiation necrosis. The results of clonogenic survival assays were compared to a parallel study with two groups of cancer patients treated with radiation: 1) patients without late side effects; 2) patients experiencing severe late sequelae. RESULTS: The survival fraction at 2 Gy (SF2) of the 2 AVM patients was 0.17 (0.14-0.19) and 0.18 (0.14-0.22). The SF2's of the cancer patients ranged between 0.25-0.38 (mean = 0.31) for the control group, and between 0. 10-0.20 (mean = 0.17) for the hypersensitive group. The SF2's of the AVM patients who developed brain necrosis were comparable to that of the hypersensitive group (p = 0.85) but significantly lower than the control group (p = 0.05). CONCLUSION: The two patients who developed radiation necrosis demonstrate increased fibroblast radiosensitivity. The SF2 of skin fibroblasts may potentially be used as a predictive assay to detect patients at risk for brain necrosis.     

Neoadjuvant Treatment with Preoperative Radiotherapy for Extremity Soft Tissue Sarcomas: Long-Term Results from a Single Institution in Turkey

Background: To assess the long term clinical outcome of preoperative radiotherapy with or withoutchemotherapy followed by limb sparing surgery in patients with non-metastatic soft tissue sarcomas (STS) ofthe extremities. Materials and Methods: Sixty patients with locally advanced STS were retrospectively analyzed.The median tumor diameter was 12 cm. All patients were treated with preoperative radiotherapy deliveredwith two different fractionation schedules (35Gy/10fr or 46-50Gy/23-25fr). Neoadjuvant chemotherapy wasadded to 44 patients with large and/or high grade tumors. Surgery was performed 2-6 weeks after radiotherapy.Chemotherapy was completed up to 6 courses after surgery in patients who had good responses. Results: Medianfollow-up time was 67 months (8-268 months). All of the patients had limb sparing surgery. The 5-year localcontrol (LC), disease free (DFS) and overall survival (OSS) rates for all of the patients were 81%, 48.1% and68.3% respectively. 5-year LC, DFS and cause specific survival (CSS) were 81.7%, 47%, 69.8%, and 80%, 60%,60% in the chemoradiotherapy and radiotherapy groups, respectively. On univariate analysis, patients who weretreated with hypofractionation experienced significantly superior LC, DFS and CSS rates with similar ratesof late toxicity when compared with patients who were treated with conventional fractionation and statisticalsignificance was retained on multivariate analysis. Conclusions: Treatment results are consistent with theliterature. As neoadjuvant chemoradiotherapy provides effective LC and CSS with acceptable morbidity, itshould be preferred for patients with large and borderline resectable STS.     

Long-term results of preoperative intra-arterial doxorubicin combined with neoadjuvant radiotherapy, followed by extensive surgical resection for locally advanced soft tissue sarcomas of the extremities.

BACKGROUND AND PURPOSE: In the 1980s a combined modality therapy of intraarterial doxorubicin, neoadjuvant radiotherapy and surgery was initiated at the Groningen University Hospital as a limb-saving treatment for locally advanced, primarily irresectable high-grade soft tissue sarcomas (STS) of the extremities. This study presents the short- and long-term results. PATIENTS AND METHODS: Between 1983 and 1987, 11 patients were treated with intraarterial doxorubicin, preoperative radiotherapy (10 x 3.5 Gy) and surgical resection. Non-radical resections received additional postoperative radiotherapy of 20-30 Gy. RESULTS: The limb-salvage rate was 91%, without local recurrences during a median follow-up of 84 months. Six patients died (55%); five from metastatic disease (45%). There were five long-term survivors with a median follow-up of 10 years. Three patients (60%) suffered serious late complications, resulting in disabilitating limb function. CONCLUSION: Although this approach is feasible as a limb-saving treatment for these unfavorable STS, long-term morbidity is high.     

Fibroblast differentiation in subcutaneous fibrosis after postmastectomy radiotherapy

In order to acquire a better understanding of the mechanism of radiation-induced fibrosis, we studied the differentiation of normal skin fibroblasts cultured from breast cancer radiotherapy patients with different risk of fibrosis. The differentiation state of fibroblasts was characterized in clonal cultures using established cytomorphological criteria. Collagen synthesis was determined by ³H-proline incorporation into pepsin-resistant protein. Radiation-induced inactivation of fibroblasts was paralleled by an increase in terminally differentiated fibrocytes, demonstrating that premature terminal differentiation is an important response to irradiation of fibroblasts from radiotherapy patients. Surviving colony-forming fibroblasts showed a change in differentiation with an increase in the ratio L : E of progenitor fibroblasts in late (L) compared to early (E) differentiation states. Furthermore, increased collagen production was observed after irradiation. The results provide evidence supporting a role of terminal fibroblast differentiation in radiation-induced fibrosis and imply that the progenitor population surviving radiotherapy might be more prone to terminal differentiation than before radiotherapy.     

Radiosensitivity measurement of keratinocytes and fibroblasts from radiotherapy patients.

Genetic diversity is believed to influence cellular radiosensitivity and individual variability in normal tissue reactions to radiotherapy. To measure normal cell radiosensitivity in vitro, we investigated a culture technique that yields keratinocyte and fibroblast cell cultures from small skin biopsy samples (average weight 32 mg). This technique uses 3T3 NIH cells as feeder cells, culture medium containing dialyzed fetal calf serum, low calcium, and various growth factors for keratinocyte growth. A calcium concentration of 4 x 10(-3) M and the use of lethally irradiated NIH 3T3 feeder cells were critical to the success of this method. Primary keratinocyte cultures were successfully obtained from nine biopsy specimens, and radiosensitivity measurements were obtained in six of the resulting strains. Keratinocytes were, in general, more radioresistant than fibroblasts derived from the same specimen. We conclude that radiosensitivity assessment of keratinocyte and fibroblast cultures derived from small punch biopsy specimens is feasible. Further studies can now be carried out to determine the degree of variability between individuals and the relationship between in vitro keratinocyte and fibroblast radiosensitivity and their value in predicting normal tissue responses to radiotherapy.     

Reduced hematopoietic function and enhanced radiosensitivity of transforming growth factor-beta1 transgenic mice

The cytokine transforming growth factor-beta1 (TGF-beta1) has been implicated in some tissue responses to radiation. Previous studies have demonstrated that exogenous TGF-beta1 increased the lethality of radiation in mice, but the effects of endogenous TGF-beta1 have not been investigated. To this end, we examined mice that are transgenic for active TGF-beta1 (Alb/TGF-beta1), over-expressed via an albumin promoter in the liver with resultant elevation of circulating levels of this cytokine. Alb/TGF-beta1 mice subjected to 8 Gy of total body irradiation at 3 or 5 weeks of age experienced significantly higher mortality than wild type age- and sex-matched controls by 1 to 2 weeks after irradiation. Alb/TGF-beta1 3 weeks of age also succumbed to 2 and 4 Gy of whole-body irradiation, while no mortality was observed in wild type mice. Four-week-old Alb/TGF-beta1 mice exhibited mild anemia and mild uremia. At one week after whole body irradiation with 2 Gy, 4-week-old Alb/TGF-beta1 mice had significantly reduced white blood cell counts, hematocrit, and platelet counts. Histopathologically, irradiated Alb/TGF-beta1 mice exhibited decreased bone marrow cellularity and decreased splenic extramedullary hematopoiesis. These results suggest that chronic over-expression of active TGF-beta1 is associated with increased radiosensitivity and that this effect may be mediated by increased sensitivity of bone marrow to the suppressive effects of radiation. Since TGF-beta1 levels can be greatly elevated in patients with certain tumors, these findings may be significant for radiotherapy. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 13-21 (2000). Published 2000 Wiley-Liss, Inc.     

Suppression of wound healing in tumor bearing animals as a model for tumor-host interaction: mechanism of suppression

Tumor wound healing was explored as a possible model for tumor-host interactions. Wound healing within tumors progressed normally through the hemorrhagic and inflammatory stages but failed at the mesenchymal ingrowth phase. Due to this failure of mesenchymal ingrowth, no significant collagen deposition could be detected within tumor wounds. Fluid collected from tumor wounds markedly altered fibroblast cytoskeletal structures and profoundly inhibited fibroblast proliferation and collagen synthesis. This suppression did not appear to be the direct consequence of tumor products, since tumor conditioned media enhanced fibroblast proliferation and had no effects on collagen synthesis and fibroblast cytoskeleton. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of lysed fibroblasts demonstrated that two polypeptides (Mr 280,000 and 240,000) were induced in or adherent to fibroblasts exposed to fluid from the tumor wound but not in fibroblasts exposed to fluid obtained from wounds in normal tissue or tumor conditioned media. These findings suggest that tumor wound healing is a model for mesenchymal inhibition within tumors but that the inhibitors are not tumor derived products.     

Radiation induced DNA damage and damage repair in human tumor and fibroblast cell lines assessed by histone H2AX phosphorylation

PURPOSE: To analyze the radiation-induced levels of gammaH2AX and its decay kinetics in 10 human cell lines covering a wide range of cellular radiosensitivity (SF2, 0.06-0.63). METHODS AND MATERIALS: Five tumor cell lines included Colo-800 melanoma, two glioblastoma (MO59J and MO59K), fibrosarcoma HT 1080, and breast carcinoma MCF7. Five primary skin fibroblasts lines included two normal strains, an ataxia telangiectasia strain, and two fibroblast strains from breast cancer patients with an adverse early skin reaction to radiotherapy. Cellular radiosensitivity was assessed by colony-forming test. Deoxyribonucleic acid damage and repair were analyzed according to nuclear gammaH2AX foci intensity, with digital image analysis. RESULTS: The cell lines tested showed a wide degree of variation in the background intensity of immunostained nuclear histone gammaH2AX, which was higher for the tumor cell lines compared with the fibroblast strains. It was not possible to predict clonogenic cell survival (SF2) for the 10 cell lines studied from the radiation-induced gammaH2AX intensity. In addition, the slopes of the dose-response (0-4 Gy) curves, the rates of gammaH2AX disappearance, and its residual expression (相似文献   

Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer

: To determine if the radiosensitivity of normal human skin fibroblasts, measured in early passage cultures, is significantly correlated with the degree of acute or late normal skin damage in patients treated for breast cancer with radiotherapy.

: In the 1970s, a series of breast cancer patients was treated at the Department of Oncology in Gothenburg, Sweden with postoperative irradiation to the parasternal region. Patients were treated bilaterally using different fractionation schedules and doses to the right and left fields. Peak acute reactions were scored on a six-point scale, and skin erythema was measured by reflectance spectrophotometry. Telangiectasia was graded over time on a six-point scale. In April 1992, two small skin biopsies were obtained from 22 patients in two treatment groups (i.e., four dose-fractionation schedules) and, using either delayed or immediate plating, fibroblast radiosensitivity was measured in early passage cultures by clonogenic survival, after high and low dose-rate irradiations. Survival at 2.0 Gy (SF2) was calculated from complete survival curves.

: To test assay reproducibility, SF2 values derived from paired biopsies of the same patient (12 cases) were compared. A reasonably good correlation (p = 0.075) was obtained for SF2s determined by high dose-rate irradiations with immediate plating, but not for delayed plating or low dose-rate treatments. The median coefficient of variation in the replicate SF2s after high dose-rate treatment and immediate plating was 13%m suggesting that the poor correlation in paired SF2 values is due to the magnitude of the uncertainty in SF2 relative to the overall spread in SF2 values between patients (CV = 28%). Individual SF2 values and averaged values from patients with data from two biopsies were compared with the acute and late clinical reactions. A significant negative correlation was found between SF2 and relative clinical response, but only when averaged high dose-rate SF2 values and telagiectasia scores were compared. There was no significant correlation between average SF2 values and acute responses or between individual SF2 measurements and either the acute or late clinical response.

: The results of this study suggest that the degree of late telangiectasia is at least partially dependent upon the intrinsic cellular radiosensitivity of normal fibroblast, but the relationship is not clear cut. Multiple replicate assays are necessary to obtain reliable estimates of fibroblast SF2 values using current techniques.     

上调HuR基因对食管鳞癌细胞Kyse450放射敏感性的影响

目的 研究HuR基因上调对于食管鳞癌细胞Kyse450放射敏感性的影响。方法 慢病毒上调Kyse450细胞HuR基因,同时选取X射线6Gy照射剂量作为干预条件。采用Western blot和qPCR技术分别检测Kyse450转染后的蛋白和RNA表达情况;CCK8试剂盒检测细胞的增殖速率;克隆形成试验检测细胞克隆形成能力;伤口愈合试验和Transwell试验检测细胞迁移能力的改变。结果 CCK8试验显示HuR基因上调后细胞的增殖能力增强,放射后这种增强趋势更加明显;平板克隆试验显示随着放射剂量的增加,两组细胞的克隆形成率都随之降低,但是过表达组的克隆形成数多于对照组;伤口愈合试验以及Transwell试验表明过表达组的伤口愈合速率和迁移能力高于对照组,放射治疗后这种差异更显著;Western blot显示放射治疗后24h过表达组细胞内MMP9、MMP2水平高于对照组。结论 HuR上调会增强食管鳞癌细胞增殖、克隆、迁移能力,降低其放射敏感性。     

A systematic overview of radiation therapy effects in soft tissue sarcomas

A systematic review of radiation therapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for evaluation of the scientific literature are described separately (Acta Oncol 2003; 42: 357-365). This synthesis of the literature on radiation therapy for soft tissue sarcomas (STS) is based on data from five randomized trials. Moreover, data from 6 prospective studies, 25 retrospective studies and 3 other articles were used. In total, 39 scientific articles are included, involving 4 579 patients. The results were compared with those of a similar overview from 1996 which included 3 344 patients. The conclusions reached can be summarized as follows: The well-established prognostic factors for tumour-related death from STS-histological grade, tumour size and age-are well documented. The importance of superficial versus deep site as well as the anatomic site is also reaffirmed to some extent. There is strong evidence that adjuvant radiotherapy improves the local control rate in combination with conservative surgery in the treatment of STS of extremities and trunk in patients with negative, marginal or minimal microscopic positive surgical margins. A local control rate of 90% has been achieved. Improvement is obtained with radiotherapy added in the case of intralesional surgery, but the local control rate is somewhat lower. More studies are needed on this issue. For STS in other anatomic sites, retroperitoneum, head and neck, breast and uterus, there is only weak indication of a benefit for the local control rate, with the use of adjuvant radiotherapy. There is still insufficient data to establish that preoperative radiotherapy is favourable compared to postoperative radiotherapy for local control in patients presenting primarily with large tumours. One small study has shown a possible survival benefit for preoperative radiotherapy. There is fairly good evidence to suggest that the preoperative setting results in more wound complications. There is no randomized study comparing external beam radiotherapy and brachytherapy. The data suggest that external beam radiotherapy and low dose rate brachytherapy result in comparable local control for high-grade tumours. Some patients with low-grade soft tissue sarcomas benefit from external beam radiotherapy in terms of local control. Brachytherapy with low dose rate for low-grade tumours seems to be of no benefit, but data are sparse. The available data are inconclusive concerning the effect of intraoperative high dose rate radiotherapy for retroperitoneal STS. Further studies are needed. Neutron radiotherapy might be beneficial for patients with low- and intermediate-grade tumours considered inoperable and for those operated with intralesional margins. More severe side effects for neutrons have been registered. In two small studies investigating hyperfractionation schedules there was no indication of improvements compared to daily fractions of 2 Gy. Further studies should be encouraged. One small study using preoperative limb perfusion with TNF alpha melphalan and +/- interferon gamma combined with postoperative radiotherapy in the case of marginal or positive surgical margin has shown excellent local control without enhanced morbidity.