The expression pattern of Ku correlates with tumor radiosensitivity and disease free survival in patients with rectal carcinoma

BACKGROUND: Preoperative radiotherapy reduces the rate of local recurrence and improves the chance of survival in patients with resectable, advanced rectal carcinoma. However, because not all tumors respond similarly to radiation, sorting out suitable patients is required to irradiate tumors rationally. The authors examined the possible role of Ku protein in determining tumor radiosensitivity and disease free survival in patients with rectal carcinoma. METHODS: The authors studied 96 patients with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, the number of cells that were stained positive for Ku protein was evaluated by immunohistochemistry. The expression pattern of Ku protein was examined for an association between tumor radiosensitivity (which was determined according to T classification downstaging, complete pathologic response, or Response Evaluation Criteria in Solid Tumors) and disease free survival. RESULTS: There was a high degree of correlation between the percentage of cells that expressed the 70-kDa Ku protein (Ku70) and the 86-kDa Ku protein (Ku86) in the tumor sections (correlation coefficient = 0.85; P < 0.001). The expression pattern of Ku protein was correlated not only with tumor radiosensitivity but also with disease free survival. Pathologic TMN classification, histopathologic grade, and Ku70 expression were significant prognostic variables for disease free survival in a multivariate analysis (P = 0.0031, P = 0.030, and P = 0.023, respectively). CONCLUSIONS: Ku70 and Ku86 raise the predictive possibility of tumor radiosensitivity. Ku may be a useful parameter for selecting patients with rectal carcinoma for preoperative radiotherapy.     

The immunohistochemical expression of DNA-PKCS and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity

PURPOSE: The DNA-PK complex is one of the major pathways by which mammalian cells respond to DNA double-strand breaks induced by ionizing radiation. This study evaluated the relationship between the immunohistochemical expression of the individual components of DNA-PK and cellular radiosensitivity in head and neck cancers. METHODS AND MATERIALS: Biopsies from patients with previously untreated squamous cell carcinomas of the head and neck were assessed for inherent tumor radiosensitivity measured as the surviving fraction at 2 Gy (SF2) using a soft agar clonogenic assay. Paraffin-embedded tumor material from 64 successfully grown specimens was immunohistochemically stained for expression of DNA-PKcs and Ku (p70/p80). The same tumor material was previously analyzed for the immunohistochemical expression of p53. RESULTS: A significant correlation was found between the degree of expression of DNA-PKcs and Ku (p70/p80) (r = 0.55, p<0.001). There were no overall significant differences in the levels of expression of DNA-PKcs and Ku (p70/p80) in tumors from patients of either sex, different sites, histologies, and stages. No relationship was found between SF2 and the expression of either DNA-PKcs (r = 0.22, p = 0.081) or Ku (p70/p80) (r = 0.064, p = 0.62). Comparison with previous immunohistochemical characterization showed no significant correlations between the expression levels of p53 and either DNA-PKcs (r = 0.093, p = 0.46) or Ku (p70/p80) (r = -0.17, p = 0.17). CONCLUSIONS: This study suggests that determining the immunohistochemical expression of DNA-PK in head and neck cancers from multiple sites does not have a role as a predictive assay of tumor in vitro radiosensitivity.     

Tumour vascularity is a significant prognostic factor for cervix carcinoma treated with radiotherapy: independence from tumour radiosensitivity.

The aim of the study was to investigate the relationship between intrinsic radiosensitivity and vascularity in carcinoma of the cervix given radiotherapy, and assess whether more refined prognostic information can be gained by combining the two parameters. A retrospective study was carried out on 74 patients with locally advanced carcinoma of the cervix. Formalin-fixed, paraffin-embedded tumour biopsies were stained with anti-factor VIII using immunohistochemistry. Vascularity was scored using the intra-tumour microvessel density (IMD), or 'hot-spot', technique. For the same patients, the measurement of intrinsic radiosensitivity (SF2) had been made previously on the same pretherapy samples. Patients were stratified by the median IMD and SF2 scores. Women with radioresistant and highly vascular tumours had poorer 5-year survival (P = 0.0005, P = 0.035 respectively) and local control (P = 0.012, P = 0.077 respectively) than those with radiosensitive and poorly vascular tumours. No significant correlation was seen between IMD and SF2. Multivariate analysis (including tumour stage and patient age) showed that only SF2 and IMD were significant prognostic factors for survival. Patients with both a radioresistant and highly vascular tumour had a 5-year survival level of 18% compared to 77% for those patients with a radiosensitive and poorly vascularized tumour. Tumour angiogenesis and cellular radiosensitivity are independent prognostic factors for cervix carcinoma treated with radiotherapy. Allowing for tumour radiosensitivity increases the prognostic significance of vascularity measurements in cervix tumours.     

DNA-PKcs、Ku80及ATM备选宫颈癌放疗增敏靶点的体外研究

背景与目的:DNA双链断裂(DNA double strand break,DSB)是细胞受辐射后最致命的损伤,而DNA依赖蛋白激酶催化亚单位(DNA-dependent protein kinase catalytic subunit,DNA-PKcs)、Ku80和ATM(ataxia-telangiectasia mutated)为DSB的主要修复蛋白.宫颈癌是以放疗为主要治疗手段的肿瘤.但其肿瘤细胞对放射线的敏感性不同.本实验拟研究3种DSB修复蛋白的表达与宫颈癌细胞放射敏感性的关系.并探讨DSB修复蛋白成为宫颈癌放疗增敏靶点的可能性.方法:免疫组化法检测41例宫颈癌患者组织中DNA-PKcs、Ku80和ATM蛋白的表达情况;Western blot检测8株肿瘤细胞(包括4株宫颈癌细胞)中3种蛋白的表达,克隆形成实验检测SF2 (suivival fraction at 2 Gv)、α值,分析蛋白表达水平和SF2、α值的关系;利用靶向抑制DNA-PKcs的shRNA表达质粒和小分子抑制剂LY294002,分别抑制HeLa细胞DNA-PKcs蛋白表达和活性后,克隆形成实验和流式细胞仪检测HeLa细胞受6 MVX线照射后的SF2、α值和凋亡率变化.结果:在41例宫颈癌组织中,Ku80、DNA-PKcs和ATM的阳性率分别为70.73%、68.29%和19.51%:8株肿瘤细胞中Ku80、DNA.PKcs和ATM蛋白的相对表达量与各细胞SF2、α值各不相同,作Pearson线性相关分析后得出DNA-PKcs的表达水平与SF2之间有明显的正相关关系(r=0.72,P=0.04);靶向抑制DNA-PKcs的shRNA可以促进HeLa细胞的放射敏感性,其SF2值为0.37,显著低于对照HeLa细胞的0.53(P＜0.05);单独接受50 μmol/L LY294002作用1 h HeIa细胞的凋亡率未见明显增加,但先经LY294002处理再照射6 Gy的HeLa细胞在48 h和72 h的凋亡率比单独照射6 Gy的HeLa细胞凋亡率显著增加(48 h点:t=3.25,P=0.03;72h点:t=3.01,P=0.04).结论:DNA-PKcs在宫颈癌组织中表达较高,且其表达水平可以预示肿瘤细胞的放射敏感性:抑制DNA-PKcs的表达或活性可以促进HeLa细胞的放射敏感性.     

Expression of non-homologous end joining factor,Ku80, is negatively correlated with PD-L1 expression in cancer cells after X-ray irradiation

The growing importance of antitumour immunity by cancer immunotherapy has prompted studies on radiotherapy-induced immune response. Previous studies have indicated that programmed cell death-1 ligand (PD-L1) expression is regulated by DNA damage signalling. However, PD-L1 up-regulation after radiotherapy has not been fully investigated at the clinical level, particularly in the context of expression of DNA repair factors. The present study examined the correlation of mRNA expression between PD-L1 and non-homologous end joining (NHEJ) factors using The Cancer Genome Atlas database analysis. Among NHEJ factors, Ku80 mRNA expression was negatively correlated with PD-L1 mRNA expression levels in several types of cancer (colon adenocarcinoma, breast invasive carcinoma, skin cutaneous melanoma, lung adenocarcinoma, head and neck squamous cell carcinoma, uterine corpus endometrial carcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma). To verify the negative correlation in clinical samples, the present study analysed whether Ku80 expression levels affected PD-L1 up-regulation after radiotherapy using cervical squamous cell carcinoma samples. Quantitative evaluation using software analysis of immunohistochemically stained slides revealed that patients with low Ku80 positivity in biopsy specimens demonstrated increased PD-L1 expression levels after 10 Gy irradiation (Spearman''s rank correlation coefficient=−0.274; P=0.017). Furthermore, PD-L1 induction levels in tumour cells after 10 Gy of irradiation were significantly inversely correlated with Ku80 expression levels (Spearman''s rank correlation coefficient=−0.379; P<0.001). The present study also confirmed that short interfering RNA-mediated Ku80 depletion was associated with greater X-ray-induced PD-L1 up-regulation in HeLa cells. These results indicated that radiotherapy could enhance PD-L1 induction in tumour cells with low Ku80 expression in a clinical setting. Furthermore, these data highlighted Ku80 as a potential predictive biomarker for immune checkpoint therapy combined with radiotherapy.     

Expression of DNA damage response proteins and complete remission after radiotherapy of stage IB-IIA of cervical cancer

The primary aim of this study was to investigate if the expression of the DNA damage identifying protein DNA-PKcs known to be involved in DNA repair after treatment with ionising radiation can be used as a predictive marker for radiotherapy (RT) response in cervical cancer. Formalin-fixed primary tumour biopsies from 109 patients with cervical cancer, FIGO-stage IB-IIA, treated with preoperative brachytherapy followed by radical surgery were analysed by immunohistochemistry. In addition, correlation studies between early pathological tumour response to radiation and expression of Ku86, Ku70, Mdm-2, p53 and p21 in primary tumours were also performed. We found that tumour-transformed tissue shows positive immunostaining of DNA-PKcs, Ku86 and Ku70, while non-neoplastic squamous epithelium and tumour-free cervix glands show negative immunoreactivity. Expression of DNA-PKcs positively correlated with both Ku86 and Ku70, and a statistically significant correlation between the Ku subunits was also found. After RT, 85 patients demonstrated pathologic complete remission (pCR), whereas 24 patients had residual tumour in the surgical specimen (non-pCR). The main finding of our study is that there was no correlation between the outcome of RT and the expression of DNA-PK subunits. Positive p53 tumours were significantly more common among non-pCR cases than in patients with pCR (P=0.031). Expression of p21 and Mdm-2 did not correlate with the outcome of RT.     

Expression of Ku80 correlates with sensitivities to radiation in cancer cell lines of the head and neck

The Ku protein is essential for the repair of a majority of DNA double-strand breaks in mammalian cells. The purpose of this study was to investigate the relationship between the expression of Ku70/80 and sensitivity to radiation in cancer cell lines of the head and neck. The sensitivity to radiation in various head and neck cancer cell lines (AMC-HN-1 to -9) was analyzed by colony forming assay. Of the nine cell lines examined, the most radiosensitive cell line (AMC-HN-3) and the most radioresistant cell line (AMC-HN-9) were selected for this experiments. The expression of Ku70/80 was examined after irradiation using real time PCR, Western blotting and immunofluorescence in two different cell lines. Cell cycle distribution after irradiation were analysed. A differential radioresponse was demonstrated by expression of Ku70/80 in AMC-HN-3 and AMC-HN-9 cells. While the expression of Ku70 was slightly increased in the radioresistant AMC-HN-9 cell line, the expression of Ku80 was remarkably increased, suggesting a correlation between Ku80 expression and radiation resistance. Overexpression of Ku80 plays an important role in the repair of DNA damage induced by radiation. Ku80 expression may provide an effective predictive assay of radiosensitivity in head and neck cancers.     

Levels of the DNA repair enzyme human apurinic/apyrimidinic endonuclease (APE1, APEX, Ref-1) are associated with the intrinsic radiosensitivity of cervical cancers.

A study was made of the relationship between the intrinsic radiosensitivity of human cervical tumours and the expression of the DNA repair enzyme human apurinic/apyrimidinic endonuclease (HAP1). The radiosensitivity of clonogenic cells in tumour biopsies was measured as surviving fraction at 2 Gy (SF2) using a soft agar assay. HAP1 expression levels were determined after staining of formalin-fixed paraffin-embedded tumour sections with a rabbit antiserum raised against recombinant HAP1. Both measurements were obtained on pretreatment biopsy material. All 25 tumours examined showed positive staining for HAP1, but there was heterogeneity in the level of expression both within and between tumours. The average coefficients of variation for intra- and intertumour heterogeneity were 62% and 82% respectively. There was a moderate but significant positive correlation between the levels of HAP1 expression and SF2 (r = 0.60, P = 0.002). Hence, this study shows that there is some relationship between intrinsic radiosensitivity and expression of a DNA repair enzyme in cervical carcinomas. The results suggest that this type of approach may be useful in the development of rapid predictive tests of tumour radiosensitivity.     

Prediction of tumor radiosensitivity in rectal carcinoma based on p53 and Ku70 expression

The identification of predictive indicators of radiosensitivity is extremely useful in selecting patients suited for preoperative radiotherapy and avoiding unnecessary preoperative treatment. In this study, we evaluated the possible role of the immunohistochemical expression pattern of p53 and Ku70 protein in determining tumor radiosensitivity in rectal cancer before preoperative irradiation. We examined pretreatment biopsy materials from 111 patients by immunohistochemistry. The expression pattern of p53 and Ku70 was evaluated for association with tumor radiosensitivity, which was defined according to the criteria of the Japanese Research Society for Cancer of the Colon and Rectum. There was a significant correlation between the expression pattern of p53 and tumor radiosensitivity (P = 0.045); Ku70 and tumor radiosensitivity (P < 0.001); and the combination of p53 and Ku70, and tumor radiosensitivity (P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in both p53 and Ku70-positive cases for radioresistance were all superior to those of the group positive for p53 alone. In conclusion the examination of the combination of p53 and Ku70 may predict the radiosensitivity of rectal cancer before preoperative irradiation.     

EXPRESSION AND SUBCELLULAR LOCALIZATION OF DNA-PK IN NASOPHARYNGEAL CARCINOMA CELL LINES CNE1 AND CNE2 WITH DIFFERENT RADIOSENSITIVITY

Exploring mechanism of radioresistance and searching for some suitable radiosensitized approaches isone of the ways to improve the curative rate of nasopharyngeal carcinoma. As we know, radiosensitivity is highly correlated with the number of DNA double strand breaks (DSBs) and the extent of it’s repair[1], and the ability of DSBs repair is one of the important factors influencing radiosensitivity. In mammalian cells, the nonhomologous end joining (NHEJ) is the predominan pathway of DSB…     

Overexpression of Bcl-2 in squamous cell carcinoma of the larynx: a marker of radioresistance

Squamous cell carcinoma of the larynx can be treated using radiotherapy or surgery, either alone or in combination. Radiotherapy is preferred for early-stage tumours, as it spares the larynx and therefore preserves speech and swallowing. Unfortunately, approximately 15% of tumours treated this way will prove to be radioresistant, as manifest by tumour recurrence within the original radiotherapy field over the ensuing 12 months. By causing extensive DNA damage, radiotherapy aims to induce apoptosis and tumour regression. Our hypothesis was that defects in the mechanisms that recognise DNA damage, induce cell cycle arrest or control apoptosis, either alone or in combination, may be responsible for radioresistance. We therefore undertook an immunohistochemic analysis of pretreatment biopsies of radioresistant (n = 8) and radiosensitive (n = 13) laryngeal tumours. To minimise the impact of confounding factors, strict inclusion criteria were observed; all tumours were of the glottic subsite and all recurrences developed within 12 months of radiotherapy at the site of the original tumour. The expression of key proteins involved in DNA damage recognition (p53), cell cycle arrest (ATM, p16 and p21/WAF1) and apoptosis (Bcl-2 and BAX) were studied. Ki-67 was also assessed as a marker of cell proliferation to exclude low mitotic rate as a cause of radioresistance. A statistically significant correlation was observed between overexpression of Bcl-2 and radioresistance (p = 0.003, Fisher's exact test). We hypothesise that overexpression of the anti-apoptotic protein Bcl-2 allows tumour cells with extensive radiation-induced DNA damage to continue proliferating; the absence of an appropriate apoptotic response manifests clinically as radioresistance.     

Ku80蛋白在乳腺癌组织中的表达及其临床意义

目的:研究Ku80蛋白在乳腺癌的表达及与临床病理特征的关系.方法:采用免疫组化法检测65例乳腺癌组织Ku80、ER、PR、HER-2和突变型p53表达水平.结果:65例乳腺癌标本中Ku80、ER、PR、HER-2、p53阳性率分别为78.5%、40.0%、53.8%、44.6%和32.3%.Ku80表达水平与肿瘤大小、ER、PR、HER-2和p53的表达水平有关(P＜0.05),其中Ku80与HER-2密切相关(rs=0.319,P=0.010).结论:Ku80表达水平与影响乳腺癌患者预后的生物学特征相关,特别是与HER-2关系密切;Ku80与HER-2之间可能存在调控通路.     

Ku70和DNA—PKcs在鼻咽癌放疗后复发组织中的表达及其意义

目的：探讨鼻咽癌及放疗后复发鼻咽癌组织中Ku70和DNA—PKcs的表达及其与鼻咽癌放射敏感性的关系。方法：符合入组条件的64例鼻咽癌活检标本,应用免疫组织化学技术检测Ku70和DNA—PKcs的表达,并分析两者之间的关系。结果：鼻咽非角化性癌中Ku70阳性率为83．87％,DNA—PKcs阳性率为74．19％;放疗后复发鼻咽癌中Ku70阳性率为84．85％,DNA—PKcs阳性率为81．82％。Ku70及DNA—PKcs的表达在鼻咽非角化性癌与放疗后复发鼻咽癌两组间比较,差异无显著性（P〉0．05）。在放疗后复发鼻咽癌中,Ku70与DNA—PKcs表达呈正相关（P〈0．001）。结论：Ku70和DNA—PKcs在放疗后复发鼻咽癌组织中的表达具有相关性,两者尚不能作为预测鼻咽痛放射敏感性的指标。     

宫颈癌组织ICAM-1和VEGF表达与放疗敏感相关性研究

目的：研究细胞间黏附分子-1（intercellulareelladhesionmolecule-1,ICAM-1）和血管内皮生长因子（vascularendo—thalialgrowthfactor,VEGF）在宫颈鳞癌组织中的表达及其与放疗敏感性的相关性。方法：选取2007—07—01—2008—06—30在南通市肿瘤医院妇瘤科住院行根治性放疗的60例宫颈鳞癌患者。采用Realtime—PCR技术检测ICAM-1mRNA和VEGFmRNA在宫颈鳞癌组织中的表达,分析不同放疗敏感性患者IcAM-1InRNA和VEGFITIRNA表达水平差异,探讨ICAM-1rflRNA和VEGFmRNA之间的相关性。结果：宫颈鳞癌组织放疗前后ICAM-11TIRNA表达水平分别为124．57±58．64和47．38±39．27,差异有统计学意义,p=0．008;VEGFITIRNA的表达水平分别为152．75±66．92和73．46士54．41,差异有统计学意义,p=0．023;ICAM-1mRNA和VEGFmRNA的表达在放疗抵抗组和放疗敏感组中差异均有统计学意义,P值分别为0．027和0．009;近期疗效中,肿瘤消失组中ICAM-1mRNA和VEGFmRNA表达存在-定相关性,r=0．468,p=0．016;肿瘤未控组中IcAM-1nlRNA和VEGFmRNA表达存在-定相关性,r=0．693,p=0．031。远期疗效中,肿瘤治愈组中ICAM-1mRNA和VEGFmRNA表达亦存在-定相关性,r=0．457,p=0．023;肿瘤复发组中IcAM-1mRNA和VEGFmRNA表达亦存在-定相关性,r=0．637,p=0．018。结论：ICAM-1高表达与宫颈鳞癌放疗抵抗性有关,并且与VEGF的表达在放射抵抗中具有-定的相关性。     

Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer

The purpose was to study the prognostic and predictive roles of DNA protein kinase catalytic subunit (DNA-PKcs), Ku70/80 and p53 for the effect of radiotherapy in breast cancer patients. Protein expressions of Ku70/80, DNA-PKcs and p53 were examined using immunohistochemistry in tumours from 224 breast cancer patients, who were randomised to receive post-operative radiotherapy or adjuvant chemotherapy (cyclophosphamide, methotrexate, 5-fluorouracil). One hundred and twenty-nine (60%) of the tumours had low expression of Ku70/80, 122 (57%) had low expression of DNA-PKcs and 65 (30%) had altered p53 expression. None of the proteins were indicative to the prognosis of local recurrence-free survival. Even though the expression of Ku70/80 and DNA-PKcs correlated well, they were not associated with treatment outcome in the same way. Low expression of Ku70/80 predicted good effect of radiotherapy (RR=0.31, 95% CI 0.13-0.76, p=0.01). In contrast, the greatest benefit of radiotherapy over chemotherapy was seen in patients with high DNA-PKcs expression (RR=0.25, 95% CI 0.07-0.84, p=0.02). Altered p53 expression predicted poor response to radiotherapy. We believe that the results reflect the different roles of DNA-PKcs and Ku70/80 in repair and cell death regulation after DNA damage. These differences could be of importance when developing drugs that target DNA repair.     

miRNA-381表达及其与鼻咽癌放疗敏感性的关系

目的:观察人鼻咽癌细胞及组织中miRNA-381的表达变化,探讨其与放射敏感性的关系.方法:采用RT-PCR法测定正常鼻咽部上皮细胞株NP460,人鼻咽癌细胞株CNE-2,放疗抵抗细胞株CNE-2R及20例符合纳入标准的鼻咽癌组织中miRNA-381的表达.完成放疗后3个月接受影像学复查,分析患者的近期放疗疗效.所有病例都有2年或2年以上随访记录,根据随访记录制定放疗敏感性评估标准.采用克隆形成实验检测细胞的放疗敏感性.结果:入组患者根据放疗敏感性评估标准,分为放疗抵抗组(7例)和放疗敏感组(13例),放疗抵抗组的miRNA-381表达显著低于放疗敏感组(P＜0.01).克隆形成实验结果显示细胞的放疗敏感性为NP460＞ CNE-2＞CNE-2R,且有显著统计学差异(P＜0.01).RT-PCR结果显示正常鼻咽部上皮细胞株NP460中miRNA-381表达量高于鼻咽癌细胞株,放疗抵抗细胞株CNE-2R中miRNA-381表达量远低于其亲代细胞株CNE-2.近期疗效和鼻咽癌组织中miRNA-381相对表达量的相关性分析显示miRNA-381相对表达量与近期疗效呈正相关(r=0.77,P ＜0.000 1).结论:miRNA-381在放疗抵抗的鼻咽癌细胞及临床标本中的表达量显著低于放疗敏感的细胞及组织.miRNA-381相对表达量越高的鼻咽癌患者接受根治性放疗后的近期疗效越好.     

Ku70/80 gene expression and DNA-dependent protein kinase (DNA-PK) activity do not correlate with double-strand break (dsb) repair capacity and cellular radiosensitivity in normal human fibroblasts

The expression of the Ku70 and Ku80 genes as well as the activity of the DNA-dependent protein kinase (DNA-PK) were studied in 11 normal human fibroblast lines. The proteins studied are known to be part of a double-strand break (dsb) repair complex involved in non-homologous recombination, as was demonstrated for the radiosensitive rodent mutant cell lines of the complementation groups 5-7. The 11 fibroblast lines used in this study represent a typical spectrum of normal human radiosensitivity with the surviving fraction measured for a dose of 3.5 Gy, SF3.5 GY, ranging from 0.03 to 0.28. These differences in cell survival were previously shown to correlate with the number of non-repaired dsbs. We found that the mRNA signal intensities of both Ku70 and Ku80 genes were fairly similar for the 11 cell lines investigated. In addition, the DNA-PK activity determined by the pulldown assay was fairly constant in these fibroblast lines. Despite the correlation between cell survival and dsb repair capacity, there was no correlation between dsb repair capacity and DNA-PK activity in the tested normal human fibroblast lines. Obviously, in this respect, other proteins/pathways appear to be more relevant.     

Glucose transporter-1 (GLUT-1): a potential marker of prognosis in rectal carcinoma?

The aim of the study is to evaluate the pattern and level of expression of glucose transporter-1 (GLUT-1) in rectal carcinoma in relation to outcome as a potential surrogate marker of tumour hypoxia. Formalin-fixed tumour sections from 43 patients with rectal carcinoma, who had undergone radical resection with curative intent, were immunohistochemically stained for GLUT-1. A mean of three sections per tumour (range 1-12) were examined. Each section was semiquantitatively scored; 0, no staining; 1, <10%; 2, 10-50%; 3, >50% and a score given for the whole section, the superficial (luminal) and deep (mural) part of the tumour. Staining was seen in 70% of tumours. Increased staining was noted adjacent to necrosis and ulceration. A diffuse and patchy pattern of staining, with and without colocalisation to necrosis was seen. Patients with high GLUT-1-expressing tumours (score 3 vs 0-2) had a significantly poorer overall survival (P=0.041), which was associated with poorer metastasis-free survival with no difference in local control. No significant correlation was seen with other prognostic factors. There was a strong correlation between the score for the superficial and deep parts of the tumour (r=0.81), but a significant relationship with outcome was only found in the deep part (P=0.003 vs P=0.46). In conclusion, increased GLUT-1 expression in rectal tumours was an adverse prognostic factor and is worth further evaluation as a predictive marker of response to therapy.     

The lack of correlation between proliferation (Ki-67, PCNA, LI, Tpot), p53 expression and radiosensitivity for head and neck cancers.

A study was made of the relationship between measurements of radiosensitivity versus proliferation and p53 status in head and neck cancers. Inherent tumour radiosensitivity was assessed as surviving fraction at 2 Gy (SF2) using a clonogenic soft agar assay (n = 77). The results were compared to data on proliferation obtained by both flow cytometry (labelling index (LI), the potential doubling time (Tpot) n = 55) and immunohistochemistry (Ki-67 and PCNA; n = 68), together with immunohistochemical p53 expression (n = 68). There were no overall significant differences in the median values of the various parameters analysed for the different sites within the head and neck region, disease stages, grades of tumour differentiation or nodal states. A subgroup analysis showed that oropharyngeal (n = 22) versus oral cavity (n = 35) tumours were more radiosensitive (P = 0.056) and had a higher Ki-67 index (P = 0.001). Node-positive tumours had higher LI (P = 0.021) and a trend towards lower Tpot (P = 0.067) values than node-negative ones. No correlations were seen between SF2 and any of the parameters studied. The long-standing dogma of an increased radiosensitivity of rapidly proliferating cells in contrast to slowly proliferating cells was not confirmed. The study shows that parallel measurements of different biological markers can be obtained for a large number of patients with head and neck cancers. The independence of the various parameters studied suggests that there may be potential for their combined use as prognostic factors for the outcome of radiotherapy.     

DNA依赖蛋白激酶与大肠癌淋巴转移相关性研究

Objective:To investigate DNA-dependent protein kinase(DNA-PK)expression,and its relationship with lymphatic metastasis in colorectal cancer.Methods:Tumor tissues from 60 patients,divided into two groups according to lymphatic metastasis,were immunohistochemically stained to detect the DNA-PK expression including Ku70,Ku80 and PKcs proteins.Results:Positivity of both Ku70 and Ku80 in colorectal cancer was negatively correlated with lymphatic metastasis with an rvalue of-0.57 and -0.38,respectively.Similar correlation was found between Ku expression,especially Ku70.and long-term survival.PKcs,however,displayed no significant correlation.Statistical analysis failed to detect any correlation between DNA-PK expression,and clinical characteristics,such as age,sex,tumor Jocation,tumor thickness and distant metastasis(P＞0.05).Conclusion:DNA-PK expression,especially Ku70 expression,is negatively correlated with lymphatic metastasis,and the survival of patients with colorectal cancer.Ku70 expression may be a potential indicator for the preoperative evaluation,and prognosis in colorectal cancer.