Expression of p53 in preneoplastic and early neoplastic bronchial lesions

p53 alteration has been reported to be an early event in bronchial carcinogenesis. Our study purpose was to determine the rate of p53 expression in the various preneoplastic and early neoplastic bronchial lesions obtained by biopsy during fluorescence bronchoscopy and to analyse its association with patients characteristics. Various stages of preneoplastic lesions as well as radio-occult lung cancer were studied in biopsies obtained by fluorescence bronchoscopy. We assessed the expression of p53 by immunohistochemistry using monoclonal antibody clone DO7. The p53 expression was considered as positive if > or = 1% of cells were positive and the level of positivity was expressed in percentage of positive cells. Fourteen patients were included in each category of preneoplastic lesions. At the threshold of 1% of positive cells p53 expression was observed in 28.5% of the patients with a histologically normal epithelium. This number of positive patients increased with the severity of preneoplastic lesions and reached 100% in the mild dysplasia. The mean rates of p53 positive cells for normal epithelium, hyperplasia, metaplasia, mild and severe dysplasia, carcinoma in situ and invasive radio-occult carcinoma were respectively 0.9, 3.4, 9.1, 20.5, 50.2, 34.7 and 42.5%. There was no statistically significant correlation between p53 expression and patient characteristics such as sex, age, smoking habits and indication for fluorescence bronchoscopy. The alteration of p53 expression in patients with high risk of lung cancer was an early event: this abnormality increased with the severity of the lesions, without significant correlation with patient characteristics.     

p53 mutation and allelic loss of chromosome 3p, 9p of preneoplastic lesions in patients with nonsmall cell lung carcinoma

BACKGROUND: An accumulation of mutations can result in carcinogenesis. Comparing genetic alterations in preneoplastic lesions with those seen in cancer in the same patient may be helpful in the early diagnosis of lung carcinoma or preneoplastic lesions. METHODS: To identify genetic alterations that may play a role in the development of nonsmall cell lung carcinoma (NSCLC), the authors examined the p53 gene and microsatellite markers on chromosome 3p (D3S643, D3S1317), 9p (D9S171, IFNA) in 35 bronchial metaplastic lesions and 28 alveolar hyperplastic lesions from 61 patients. RESULTS: A total of 8 metaplastic lesions (1 squamous metaplasia and 7 dysplasias) and 3 alveolar hyperplastic lesions (with atypia) showed genetic alterations, including loss of heterozygosity (LOH) of 3p, 9p and mutations of the p53 gene. In an analysis of microsatellite markers, 5 of 35 cases of squamous cell carcinoma (SCC) and 3 of 26 cases of adenocarcinoma (Ad) showed LOH in both preneoplastic lesions and synchronous cancers. Nine patients (25.7%) with SCC and 6 patients (23.1%) with Ad were shown to have mutations of the p53 gene by single-strand conformation polymorphism. In 2 of these 9 patients with SCC, the same mutation was observed in both dysplasia and SCC. CONCLUSIONS: These findings suggest that several genetic alterations may occur in preneoplastic lesions or the early stage of SCC of the lung, whereas the genetic alterations examined appeared to occur relatively late in the pathogenesis of pulmonary adenocarcinoma.     

p53 protein accumulation and genomic instability in head and neck multistep tumorigenesis.

Head and neck cancer develops in a multistep process and is associated with increasing frequencies of p53 alterations and with increasing genomic instability. To study the relationship of p53 alterations and genomic instability during head and neck tumorigenesis, we analyzed p53 protein expression and chromosome 9 and 17 polysomy in 48 squamous cell carcinomas of the head and neck and their adjacent normal epithelium (31 sites), hyperplastic (24 sites), and dysplastic lesions (26 sites). Normal oral epithelium obtained from seven nonsmoking, cancer-free individuals served as negative controls. Six (19%) of 31 lesions in adjacent normal epithelium, 7 (29%) of 24 hyperplastic lesions, 12 (46%) of 26 dysplastic lesions, and 28 (58%) of 48 squamous cell carcinomas expressed p53. In contrast, no normal control epithelium had detectable p53 expression. To determine the relationship between dysregulated p53 expression and genomic instability during tumorigenesis, we compared p53 immunohistochemistry distributions and chromosome polysomy levels (by chromosome in situ hybridization) in different histological groups associated with tissue progression. Although the degree of chromosome polysomy increased for all of the groups during histological progression, lesions with dysregulated p53 expression showed nearly 2-4-fold increased levels of chromosome polysomy. This trend was significant for dysplastic lesions (P = 0.005 and P = 0.002 for chromosomes 9 and 17, respectively) and for squamous cell carcinoma (P = 0.005 and P = 0.002 for chromosomes 9 and 17, respectively). Image analysis studies for 28 p53-expressing tumors and their adjacent premalignant lesions demonstrated a strong spatial correlation between stepwise transitions from low to high p53 expression and increased chromosome polysomy frequencies in 13 (46%) of 28 cases. These findings suggest that altered p53 expression is associated with increased genetic instability in preneoplastic epithelium and may play a driving force for increasing the rate of accumulation of genetic events during head and neck tumorigenesis.     

Altered p16INK4a and Fhit expression in carcinogenesis and progression of human oral cancer

To further characterize the biological and clinical role of molecular alterations involved in oral squamous carcinogenesis, the immunohistochemical expression level of two tumor suppressor genes, fragile histidine triad and p16INK4a, in non-carcinomatous squamous epithelia and head and neck squamous cell carcinoma was determined. In addition, human papillomavirus infection determined by PCR assay and the use of alcohol and cigarettes were evaluated. In this study 28 non-carcinomatous squamous epithelia and 57 head and neck squamous cell carcinoma were considered. The expression levels of fragile histidine triad were lower in head and neck squamous cell carcinoma than in non-carcinomatous squamous epithelia. In contrast, p16INK4a is expressed in malignant lesions (51% of the cases analyzed), but not in non-carcinomatous squamous epithelia. No correlation between gene expression alterations of the two tumor suppressors was observed. PCR analysis showed that HPV DNA was present in 5 of the 57 malignant lesions analyzed (8.8%). None of the factors described above, despite changes in gene expression and HPV infection, appears to be associated with alcohol use and/or tobacco smoking and clinical outcome. Our data showed that fragile histidine triad and p16INK4a expression are altered in malignant lesions. Most likely, the decreasing levels of fragile histidine triad is directly involved in cancer development, while the accumulation of p16INK4a in head and neck squamous cell carcinoma may be the consequence of loss of functional tumor suppressor retinoblastoma pathway.     

Expression of TGFbeta type-II receptor in association with markers of proliferation and apoptosis in premalignant lung lesions

BACKGROUND: Analysis of the early molecular abnormalities that play an oncogenic role in the progression of pulmonary neoplasia may lead to the identification of useful markers for early detection and prognosis. In normal squamous epithelium, transforming growth factor beta (TGFbeta) regulates cell growth and differentiation via specific membranous receptors and intracellular signaling molecules (Smads). The authors previously observed that, in head and neck squamous cell carcinoma, the expression of the TGFbeta type II receptor (TbetaR-II) decreases as tumors become less differentiated and more biologically aggressive. METHODS: In this pilot study of 48 premalignant bronchoepithelial lesions, the authors evaluated the expression of TbetaR-II and 2 proliferation markers (Ki-67 and MCM2), and the amount of early DNA fragmentation as evidence of apoptosis. RESULTS: The authors observed that the progression of premalignant lesions toward carcinoma in situ is accompanied by a decrease in TBR II expression and apoptosis and an increase in the expression of Ki-67 and MCM2. CONCLUSIONS: These results suggested that the TGFbeta pathway may be impaired early in the neoplastic process and that a combination of selected markers can provide a useful profile to detect preneoplastic changes in individuals at high risk for developing pulmonary carcinoma.     

E-cadherin、β-catenin及p120在上皮性卵巢癌中的表达及临床病理意义

目的:探讨黏附复合体相关蛋白E-cadherin、β-catenin及p120在人类卵巢癌组织中的表达及其与患者临床病理特征及预后的关系.方法:采用免疫组织化学染色法检测281例卵巢癌患者肿瘤组织中E-cadherin、β-catenin及p120的表达水平,分析其与临床病理特征之间的关系,比较其在卵巢癌原发灶与转移灶之间的差异.结合患者随访资料,利用Kaplan-Meier法绘制生存曲线,Log-rank法分析E-cadherin、β-catenin或p120的表达水平与卵巢癌患者预后的关系,COX回归模型分析卵巢癌患者预后的独立预测因素.结果:β-catenin在卵巢癌原发灶与转移灶间表达水平具有统计学差异(P=0.018),卵巢癌组织中p120的表达水平与患者FIGO分期(P=0.043)、组织学类型(P＜0.001)、肿瘤分级(P ＜0.001)有关,Spearman法分析证实E-cadherin与β-catenin(P=0.005)、β-catenin与p120(P ＜0.001)、E-cadherin与p120(P ＜0.001)具有相关性,卵巢癌组织中β-catenin(P=0.008)及p120(P =0.006)低表达的患者较高表达者总生存期缩短,多因素分析发现FIGO分期、β-catenin或p120表达水平是卵巢癌患者总生存期的独立预测因素.结论:鉴于黏附复合体在卵巢癌发生、浸润及转移中均发挥了重要作用,综合评估其相关蛋白E-cadherin、β-catenin及p120的表达水平,有助于判断卵巢癌的生物学行为及预测患者的预后.     

Decreased expression of the p63 related proteins beta-catenin, E-cadherin and EGFR in oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory disease and although classified by WHO as a premalignant condition, the risk for transformation into squamous cell carcinoma of the head and neck (SCCHN) is a matter of great controversy. The p63 gene encodes six different proteins which are required for development of ectodermally derived tissues such as oral mucosa, salivary glands, teeth and skin. p63 is highly expressed in SCCHN whereas decreased expression is seen in OLP. beta-catenin, E-cadherin and epidermal growth factor receptor (EGFR) are p63 related proteins, and abnormalities in their expression suggested they are involved in development of squamous cell carcinoma of the head and neck (SCCHN). In this study we mapped the expression of these p63 related proteins in OLP and matched normal healthy controls. Results showed decreased expression of beta-catenin, E-cadherin and EGFR in the vast majority of OLP samples compared with the normal controls. This is the first comprehensive study mapping expression of several p63- and SCCHN-related proteins in tissue from patients with OLP. Results showed a mixed expression pattern with OLP variably resembling normal as well as tumour tissue. Based on our present and previous data it cannot be judged whether OLP lesions are at an increased risk of malignant development.     

Loss and reduction of FUS1 protein expression is a frequent phenomenon in the pathogenesis of lung cancer.

PURPOSE: FUS1, a novel tumor-suppressor gene located in the chromosome 3p21.3 region, may play an important role in lung cancer development. Currently, FUS1-expressing nanoparticles have been developed for treating patients with lung cancer. However, the expression of Fus1 protein has not been examined in a large series of lung cancers and their sequential preneoplastic lesions. EXPERIMENTAL DESIGN: Using tissue microarrays, we examined Fus1 immunohistochemical expression in 281 non-small cell lung carcinoma (NSCLC) and 22 small cell lung carcinoma tissue specimens and correlated the findings with patients' clinicopathologic features. To investigate the expression of Fus1 in the early sequential pathogenesis of NSCLC, we studied Fus1 expression in 211 histologically normal and mildly abnormal bronchial epithelia, and 118 bronchial and alveolar preneoplastic lesions obtained from patients with lung cancer. RESULTS: Loss and reduction of expression was detected in 82% of NSCLCs and 100% of small cell lung carcinomas. In NSCLCs, loss of Fus1 immunohistochemical expression was associated with significantly worse overall survival. Bronchial squamous metaplastic and dysplastic lesions expressed significantly lower levels of Fus1 compared with normal (P = 0.014 and 0.047, respectively) and hyperplastic (P = 0.013 and 0.028, respectively) epithelia. CONCLUSIONS: Our findings show a high frequency of Fus1 protein loss and reduction of expression in lung cancer, and suggests that this reduction may play an important role in the early pathogenesis of lung squamous cell carcinoma. These findings support the concept that FUS1 gene and Fus1 protein abnormalities could be used to develop new strategies for molecular cancer therapy for a significant subset of lung tumors.     

Topographical analysis of p53 expression and DNA ploidy in early bronchial squamous cell carcinoma and preneoplastic lesions.

The significance of p53 mutations and DNA aneuploidy in carcinoma cells has been investigated on the basis of a multi-step development theory of carcinogenesis. It has, however, not been determined whether these alterations can be used as diagnostic markers for the early detection of bronchial squamous cell carcinoma (BSqCC). To address this problem, we topographically investigated p53 alterations and DNA aneuploidy in 24 X-ray-negative, early BSqCC patients with various preneoplastic lesions and in 25 non-carcinoma patients with preneoplastic lesions. Bronchial lesions (n=88) were morphologically classified as hyperplasia (HP, n=5), squamous metaplasia (SM, n=23), low-grade dysplasia (LGD, n=14), high-grade dysplasia (HGD, n=11), intraepithelial carcinoma including 'carcinoma in situ' (CIS) (IEC, n=15), and microinvasive carcinoma (MIC, n=20). Immunohistochemistry for the p53 protein and image cytometry for DNA ploidy detection were performed in serial sections of each lesion. Overexpression of p53 protein was detected in 36, 73, and 65% of the HGD, IEC, and MIC lesions, respectively. Aneuploid DNA profiles were found only in carcinoma lesions, 33% in IEC and 85% in MIC. The topographical analysis revealed two types of early BSqCCs, one with adjacent preneoplastic lesions (sequential type, n=8) and another without such lesions (de novo type, n=16). The p53 protein was frequently overexpressed in both types (sequential type, 79%; de novo type, 62%). In the sequential type, however, the p53 protein was overexpressed in HGD lesions that were directly adjacent to p53-overexpressing carcinoma lesions without exception. The present topographical study suggests that p53 mutations play an important role in the carcinogenesis of BSqCC and that p53-overexpressing HGD lesions in sequential types should be regarded as 'truly' preneoplastic lesions that actually develop into carcinomas. In addition, our study demonstrated that DNA aneuploidy might occur at times after p53 alteration with increasing frequency, as invasive growth begins. Such combination analysis of p53 immunohistochemistry and nuclear DNA ploidy in routine histology may contribute to estimates of malignant potential in preneoplastic and intraepithelial squamous lesions and provide additional information for early detection of BSqCC.     

E-cadherin expression during urothelial carcinogenesis induced by N-butyl-N-(4-hydroxybutyl) nitrosamine in rats

An alteration in the expression of E-cadherin has been observed in many epithelial neoplasms. No data exist, however, for the expression of this protein in an animal model for urinary bladder cancer. The present study investigated the expression of E-cadherin in rat urothelial preneoplastic lesions and tumours induced by oral administration of N-butyl-N-(4-hydroxybutyl) nitrosamine, during 10, 15 and 20 weeks. Simple hyperplasia and squamous metaplasia showed a similar E-cadherin pattern when compared with normal urothelium, with its expression confined to cell membrane. Thirty eight percent of the nodular hyperplasia, 41.4% of the dysplasia and 100% of the papillomas showed a weak E-cadherin expression. All papillary neoplasm of low malignant potential, low-and high-grade papillary carcinoma, and invasive carcinoma revealed an abnormal staining pattern with an increase in cytoplasm reactivity and discontinuous cell membrane positivity. The loss of expression for low-grade papillary carcinoma versus simple hyperplasia, nodular hyperplasia and dysplasia was statistically significant (p = 0.0001, p = 0.007 and p=0.008, respectively). There was a similar decrease in E-cadherin expression for papillary neoplasm of low malignant potential versus simple hyperplasia, nodular hyperplasia and dysplasia (p = 0.0001; p = 0.001 and p=0.0001, respectively). These results suggest that alteration in the expression of this adhesion molecule in rat may be indicative of tumour progression in N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder cancer.     

肺癌浸润前病变及基因改变

对肺癌浸润前病变的认识及其发生发展相关基因的研究有助于肺癌的防治。主要的肺癌浸润前病变有三种鳞状上皮非典型增生(SD)和原位癌(CIS)、不典型腺瘤样增生(AAH)及弥漫性特发性肺神经内分泌细胞增生(DIPNECH),三者被认为有可能分别发展为肺鳞癌、外周型腺癌和类癌。临床通过纤支镜、细胞学、影像学及形态定量分析和DNA含量测定早期发现肺癌,荧光纤维支气管镜检查、恶性相关改变分析及hnRNP A2/B1检测可提高肺癌浸润前病变检出率。肺癌的早期并无特异性临床表现,因此,寻找敏感而又特异的标志物是提高肺癌早期诊断的关键。癌基因C-myc、ras和bcl-2上调表达及抑癌基因p53、p16、Rb及FHIT基因突变、异常甲基化及缺失被认为是肺癌发生的早期分子事件,在早期癌的诊断及高危人群的早期监测等方面有很高的应用价值。染色体3p的缺失是肺癌最频繁和最早发生的遗传学改变。CD44S和(或)CD44V6表达的改变是所有肺癌前病变的一个特征,可作为肺癌前变化的标记。将肺癌浸润前病变的病变特点、早期发现及诊断的新方法、相关癌基因及抑癌基因的异常改变及肺癌的遗传易感性进行综述。     

Epithelial-cadherin and beta-catenin expression changes in pancreatic intraepithelial neoplasia.

PURPOSE: Cadherins and associated catenins are important mediators of epithelial cell-cell adhesion, as well as the Wnt-signaling pathway. Significant changes in their expression or structure have been implicated in malignancy. This study aimed to investigate the epithelial-cadherin (E-cadherin) and beta-catenin expression changes during multistage, pancreatic ductal carcinogenesis. EXPERIMENTAL DESIGN: Ninety-four Whipple resection specimens were retrieved from the surgical pathology files of the University Health Network (Toronto, Canada), from which tissue microarray blocks containing 36 pancreatic ductal adenocarcinomas, 34 PanIN-1A lesions, 28 PanIN-1B lesions, 27 PanIN-2 lesions, 16 PanIN-3 lesions, and 32 normal ducts were constructed. The E-cadherin, beta-catenin, and the phosphorylated glycogen synthase kinase-3beta of the Wnt/beta-catenin pathway were immunohistochemically evaluated in these duct/PanIN lesions. RESULTS: There was marked increase in the cytoplasmic E-cadherin expression in PanIN lesions (P < 0.0001) and adenocarcinoma (P = 0.005) compared with normal pancreatic ducts. In contrast, reduced/loss of E-cadherin membranous expression was also significant in ductal adenocarcinoma compared with both the PanIN lesions (P < 0.0001) and normal ducts (P = 0.05). The beta-catenin expression showed significantly more frequent aberrant nuclear localization in high-grade PanIN lesions, particularly PanIN2 and in adenocarcinoma compared with normal ducts or low grade PanIN lesions (P < 0.0001). However, there was a lack of correlation between phospho(Ser9)-glycogen synthase kinase-3beta cytoplasmic expression and beta-catenin aberrant nuclear expression (P = 0.07). CONCLUSIONS: Aberration in the expression of E-cadherin and its associated beta-catenin is evident in pre-invasive (PanIN) neoplastic pancreatic duct cells, suggesting involvement of pathways leading to beta-catenin stabilization during pancreatic duct cell carcinogenesis.     

Molecular profiling of head and neck tumors

PURPOSE OF REVIEW: Head and neck squamous cell carcinoma is the fifth most common cancer worldwide. Unfortunately, patients with the same diagnostic and prognostic profile can have markedly different clinical outcomes. This most likely results from the fact that the current taxonomy of head and neck squamous cell carcinoma groups molecularly different diseases with distinct clinical phenotypes into classifications based mainly on morphology. A combination of circumstances, including the advent of array-based technology and progress in the human genome initiative, now provides an ideal opportunity to begin performing comprehensive molecular and genetic profiling of head and neck squamous cell carcinoma. This article reviews recently reported studies that have used such approaches. RECENT FINDINGS: Comparison of gene expression profiles between head and neck squamous cell carcinoma and normal tissues showed altered expression levels of genes involved in the control of cell growth and differentiation, angiogenesis, apoptosis, cell cycle, and signaling, most of which have not been previously described in head and neck squamous cell carcinoma. Additionally, they revealed the implication of different signaling and metabolic pathways such wnt and noch, highlighting the potential role of these pathways in oral cancer development. Their results provide new insights into the carcinogenesis of head and neck squamous cell carcinoma as well as a source of potential prognostic and predictive markers and targets for its prevention and therapeutics. SUMMARY: Although the sample sizes of these studies were small and their findings therefore require further validation in larger trials, such preliminary results provide important clues to the understanding of the various gene networks implicated in oral carcinogenesis and may contribute to the selection of target genes for possible molecular diagnosis and therapy in the future.     

Differential expressions of cyclin-dependent kinase inhibitors (p27 and p21) and their relation to p53 and Ki-67 in oral squamous tumorigenesis

The cyclin-dependent kinase inhibitors p27Kip1 and p21WAF1/Cip1 play important roles in cell-cycle regulation. Although alterations of these genes have been linked to tumorigenesis of several human carcinomas, their involvement in head and neck squamous tumorigenesis is rarely investigated. To determine the role of these genes in the evolution of squamous carcinoma of the head and neck we evaluated their protein expression by immunohistochemistry in non-dysplastic squamous epithelium, premalignant lesions and oral squamous carcinomas. The p53 gene and Ki-67 expressions were correlated with traditional clinicopathologic variables. Our study shows that in histologically non-dysplastic squamous epithelium, p27 expression was noted mainly in superficial differentiated cells, whereas p21, p53 and Ki-67 staining was observed in basal and suprabasal cells. In dysplasia, divergent expression between p27 and p21 was observed: p27 precipitously decreased and p21, p53, and Ki-67 increased with histologic progression. In squamous carcinomas, p27 was mainly expressed in well differentiated tumor cell nests, while the expressions of p21, p53, and Ki-67 were variable in the poorly differentiated tumor areas. A significant inverse relationship between p27 expression and those of p21, p53, and Ki-67 was observed, but no significant association between any of these markers and clinicopathologic factors was noted in this cohort. Our study indicates that: i) down-regulation of p27 and up-regulation of p21 are associated with early progression of HNSC, ii) p21 expression correlates positively with proliferation while p27 correlates positively with cell differentiation and iii) concurrent p27 and p21 expression analysis may allow for better assessment of HNSC progression.     

Modulation of neoangiogenesis in bronchial preneoplastic lesions.

We have previously demonstrated that vascular count significantly increases in the preneoplastic lesions of the bronchial tree, starting from very low levels in the normal epithelium to a significantly higher number of microvessels in moderate dysplastic lesions and in situ carcinomas. Vascular endothelial growth factor (VEGF) protein expression has shown to be strictly associated with neovascularization both in human cancer and in various type of preinvasive lesions. A number of studies have demonstrated that mutant p53 is involved in the regulation of angiogenesis, and immunohistochemical detection of the p53 protein is associated with p53 gene mutations. In this study we looked for possible correlation between p53 protein detection, VEGF expression and vascular count in a series of preneoplastic and neoplastic lesions of the bronchial tree in order to investigate the angiogenic pattern and its genetic control in the early steps of bronchial cancer development. Twenty-four retrospective bronchial lesions with different grades of dysplasia and a case of normal bronchial epithelium were analysed. Surgical specimens removed from patients either confirmed, or suspect for lung carcinoma were stained immunohistochemically for CD34, VEGF, and p53. There were significant increases in microvascular density (MVD), VEGF, and p53 expression from normal bronchial epithelium through moderate dysplasia to in situ carcinoma to invasive cancer and these factors were significantly associated with moderate dysplastic lesions. A statistically significant difference was observed in MVD between hyperplastic-metaplastic, moderate dysplastic lesions and in situ carcinoma. A similar pattern was also observed for VEGF and p53 protein expression but no significant difference was observed between moderate dysplastic lesions and in situ carcinoma with regard to VEGF protein expression. The association between MVD, VEGF expression, p53 mutations and preinvasive lesions of the bronchial tree suggests that neoangiogenesis is early in non-small cell lung cancer (NSCLC) development and that p53 may have an important role in promoting angiogenesis in this human model of carcinogenesis.     

p53 and Ki-67 as markers of radioresistance in head and neck carcinoma

BACKGROUND: p53 and Ki-67 are regarded as potential interesting predictors of radioresistance, although their exact influence awaits confirmation on a large cohort of uniformly treated patients. METHODS: In a retrospective cohort of 304 patients with squamous cell carcinoma of the head and neck who were treated with radical radiotherapy, the expression levels of p53 and Ki-67 were assessed by immunohistochemistry. Local control and survival curves were generated for p53 and Ki-67 using the Kaplan-Meier method. The difference between curves was calculated in univariate and multivariate analyses. RESULTS: The overexpression of p53 was associated with local treatment failure (P = 0.01) but not with survival (P = 0.09). In a Cox analysis, p53 overexpression remained an independent predictor of local failure, with a relative risk of local failure of 1.5 (P = 0.05). Low proliferation (Ki-67 < 20%) was a significant factor in local failure for patients with tumors of the oral cavity only (P = 0.01). Patients with both unfavorable immunohistochemical markers (p53 overexpression and low proliferation) had a 45% rate of local control compared with a 67% rate for all other combinations (P = 0.002). This association was even more significant in patients with T1-T2 lesions (45% vs. 77%; P = 0.0002). CONCLUSIONS: The results support the role of p53 as an independent predictor of local failure in patients with squamous cell carcinoma of the head and neck who are treated by radical radiotherapy, suggesting that it may predict radioresistance. Combined with p53, Ki-67 may help in the better selection of patients for radiotherapy, especially for patients with early-stage tumors. Prospective studies are now needed to confirm these results and to define better the role of these markers in the management of patients with head and neck carcinoma.     

Expression of facilitative glucose transport proteins during development of squamous cell carcinomas of the head and neck

Positron emission tomography studies on malignant head and neck tumors have shown that tumor growth and elevated glucose uptake are associated. On a molecular level, glucose uptake is mediated by specific glucose transport proteins, which exhibit an altered expression in head and neck malignant neoplasms. However, it is unknown when during development of squamous cell carcinomas an alteration of the expression of glucose transport proteins occurs. We have studied the expression of different facilitating glucose transport proteins (GLUT 1, 2, 3 and 4) by immunohistochemistry in a variety of preneoplastic and neoplastic mucosal lesions of the head and neck. We have observed weak expression of GLUT 1 in normal mucosa, a marked expression of GLUT 1 throughout preneoplastic lesions, which correlated well with the degree of dysplasia. In squamous cell carcinomas of the head and neck (HNSCC) and metastases, GLUT 1 was always expressed strongly. In contrast, GLUT 2, 3 and 4 were not detected in any of the epithelial tissues examined. The increased expression of GLUT 1 in dysplastic lesions and its sustained expression in SCC indicate that changes of GLUT 1 expression are early events during development of HNSCC. Therefore, the detection of GLUT 1 might be a reliable marker in the diagnosis of premalignant lesions of the oropharyngeal mucosa.Int. J. Cancer 80:194–198, 1999. © 1999 Wiley‐Liss, Inc.     

Niban gene is commonly expressed in the renal tumors: a new candidate marker for renal carcinogenesis

Functional inactivation of tuberous sclerosis 2 gene (Tsc2) leads to renal carcinogenesis in the hereditary renal carcinoma Eker rat models. Recent studies revealed a role of tuberin, a TSC2 product, in suppressing the p70 S6 kinase (p70S6K) activity via inhibition of mammalian target of rapamycin (mTOR). Phosphorylated S6 protein, a substrate of p70S6K, was expressed in the early lesions in Eker rats, and this expression was suppressed by the treatment of rapamycin, an inhibitor of mTOR. We previously isolated the novel gene Niban expressed in renal carcinogenesis of Eker rats. In this study, we demonstrated that the expression of Niban was detected from early preneoplastic lesions in Eker rats. Interestingly, in contrast to the phosphorylated S6 protein, the expression of Niban was unchanged and early lesions still remained even after treatment with rapamycin. These results might suggest the existence of another pathway independent of mTOR-S6K pathway in Tsc2 mutant renal carcinogenesis. In addition, Niban was also expressed in other renal carcinoma models, including Tsc1 and Tsc2 knockout mice, and various types of human renal cell carcinomas. Thus, Niban was commonly expressed in renal carcinomas and might be a new marker for renal carcinogenesis.