食管癌前病变及原位癌组织中Ki67、p53、iNOS的异常表达

目的研究食管癌高发区癌前病变及癌活检组织标本中Ki67、p53蛋白的异常表达,探讨其与食管癌变的关系及作为早期癌变生物学标志物的可能性。方法对来自食管癌高发区河北磁县的正常食管黏膜组织和轻度、中度、重度不典型增生上皮以及原位癌活检组织共366例,应用免疫组化技术对食管癌变过程中Ki67、p53蛋白的异常表达进行研究。结果在正常黏膜、轻度、中度、重度不典型增生及原位癌组织中,Ki67异常表达检出率分别为0(0/25)、40.5%(30/74)、61.3%(65/106)、76.5%(39/51)和90.0%(72/80),其中异常表达程度在中度以上者分别占0(0/25)、2.7%(2/74)、11.2%(12/106)、41.2%(21/51)和58.8%(47/80);p53蛋白异常表达的阳性率分别为4%(1/25)、39.1%(27/69)、57.5%(61/106)、52.9%(27/51)和67.9%(53/78),其中异常表达程度在中度以上者分别占0(0/25)、10.1%(7/69)、24.5%(26/106)、39.2%(20/51)和48.7%(38/78)。p53蛋白及Ki67在正常黏膜中的表达,与不典型增生总体及原位癌组织的差异均有显著性(P＜0.001)。等级相关分析结果显示,p53、Ki67表达异常与组织学分级均显著相关（相关系数r分别为0.3597和0.5837,P值均＜0.001),而且p53蛋白与Ki67表达之间也具有显著相关性（r=0.5432,P＜0.001）。结论Ki67、p53蛋白异常表达与食管癌癌变过程显著相关,p53基因表达异常及细胞增殖异常与食管上皮的早期癌变有关。p53及Ki67表达改变的时相分布,有可能成为在食管癌前人群中确立高危个体和选择重点化学预防个体的分子生物学标记。p53改变可促使上皮细胞增殖。     

Prognostic value of cyclin B1 in patients with esophageal squamous cell carcinoma

BACKGROUND: It has been reported that p53 regulates the G2-M checkpoint transition through cyclin B1, and it has been suggested that p53 plays an important role in the development and progression of various malignancies. The objective of the current study was to clarify the role of the cell cycle regulators, cyclin B1 and p53, in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Tissue samples from 71 patients with ESCC were included in the current study. Expression levels of cyclin B1 and p53 in samples of normal squamous epithelium, dysplasia, and tumor cells from patients with ESCC were analyzed by immunohistochemistry. RESULTS: Several cells in the basement layer of normal epithelium expressed cyclin B1. The number of cyclin B1 positive cells tended to increase as the degree of dysplasia increased from low grade to high grade. More than 20% of tumor cells were cyclin B1 positive in 38 patients (49.3%). Several clinicopathologic parameters, including macroscopic configuration (P < 0.01), pathologic tumor status (P < 0.05), pathologic lymph node status (P < 0.001), pathologic metastatic status (P < 0.01), tumor stage (P < 0.0001), and invasion of lymphatic vessels (P < 0.05), were correlated with the overexpression of cyclin B1. Elevated expression levels of cyclin B1 also were correlated with a poor prognosis in patients with ESCC in univariate analysis (P < 0.0001) and multivariate analysis (P = 0.0135). In contrast, p53 expression exhibited no significant correlation with the level of cyclin B1 expression and was not associated with prognostic parameters in patients with ESCC. CONCLUSIONS: These findings suggest that cyclin B1 is involved in the pathogenesis of carcinoma of the esophagus and that elevated levels of cyclin B1 expression, but not p53 expression, may indicate a poor prognosis for patients with ESCC.     

Analysis of Ki-67, p53 and Bcl-2 expression in the dysplasia-carcinoma sequence of Barrett's esophagus.

The grading of dysplasia in Barrett's esophagus has prognostic importance, however observer variation limits the reliability of simple histological analysis alone. We investigated Ki-67, p53 and Bcl-2 expression in Barrett's esophagus, in the sequence from Barrett's low-grade dysplasia to high-grade dysplasia and infiltrating adenocarcinoma. Forty-four esophagectomy specimens were utilized: 39 specimens with esophageal dysplasia and adenocarcinoma and 5 specimens with esophageal dysplasia only. This gave 83 sections (2 sections for specimens with dyplasia and carcinoma) examined from 44 patients. The sections were examined for Ki-67, p53 and Bcl-2 reactivity by immunohistochemistry. Low-grade dysplasia was present in 14 sections, high-grade dysplasia in 30 sections and carcinoma in 39 sections. Ki-67 expression occurred in 2 out of 14 (14%) sections with low-grade dysplasia, in 22 out of 30 (73%) sections with high-grade dysplasia and in 34 out of 39 (87%) sections with carcinoma (p<0.001). p53 protein expression was found in 1 of 14 (7%) sections with low-grade dysplasia, in 18 of 30 (60%) sections with high-grade dysplasia and in 33 of 39 (85%) sections with carcinoma (p<0.001). Expression of Bcl-2 was found in 11 of 14 (84%) sections with low-grade dysplasia but immunoreactivity was not seen in any section with high-grade dysplasia or Barrett's carcinoma. Our results indicate that overexpression of Ki-67, Bcl-2 protein and p53 mutations can be identified as early events during neoplastic progression in Barrett's esophagus. These data support the hypothesis that, in the progression of Barrett's metaplasia to adenocarcinoma, the balance of proliferation/apoptosis plays an important role.     

食管黏膜癌变过程中组织细胞增殖、凋亡和p53表达的变化

目的探讨食管黏膜癌变过程中增殖、凋亡和p53表达的变化及临床意义。方法对连续胃镜检查对象818例进行食管黏膜活检和病理组织学检查,并应用TUNEL法检测凋亡指数、免疫组织化学法检测增殖指数和p53表达。结果818例食管活检组织中,正常上皮694例,单纯增生39例,轻中度异型增生24例,食管鳞癌61例。在正常上皮→单纯增生→轻中度异型增生→鳞癌中,随分化程度的进展,凋亡指数（AI）等级逐渐降低,增殖指数（PI）等级和p53表达等级则逐渐增高,差异均有统计学意义。正常上皮中AI等级与PI和p53表达等级呈负相关,PI等级与p53表达等级呈正相关。单纯增生中AI等级与p53表达等级呈负相关,PI等级与p53表达等级呈正相关。轻中度异型增生和鳞癌中AI等级、PI等级及p53表达等级之间彼此均无相关性。结论AI等级降低,PI和p53表达等级升高是食管黏膜肿瘤性生长的特征,各病理类型本身凋亡增殖和p53表达的彼此相关性可能是制约或促进癌变的机制,这些变化可以作为食管上皮恶性变倾向的参考指标。     

cyclin D1、Rb和p16基因在食管早期癌组织中的表达及其相关性研究

目的探讨cyclinD1、Rb和p16基因在食管癌发生中的作用及其相关性。方法应用免疫组织化学S-P法检测cyclinD1、Rb和p16基因在19例食管早期癌、20例异型增生以及10例正常食管黏膜标本中的表达。结果cyclinD1在早期癌中的表达高于正常食管黏膜（P〈0．05）,Rb与p16在早期癌中的表达低于正常食管黏膜（P〈0．05）。结论cyclinD1、Rb、p16与食管癌的发生有关,他们的变化是食管癌发生中的早期事件,CDK4／cyclinD1／p16／Rb通路在食管癌的早期发生过程中可能起重要作用。     

Cyclin D1 overexpression in esophageal dysplasia: a possible biomarker for carcinogenesis of esophageal squamous cell carcinoma

There is controversy as to whether esophageal squamous dysplasia is a pre-cancerous lesion or a non-cancerous lesion. In this study, we conducted an immunohistochemical investigation of cyclin D1, retinoblastoma (Rb), p16INK4 and p27KIP1 expression in 36 squamous dysplasias and 34 early squamous cell carcinomas of the esophagus. The frequency of cyclin D1 overexpression was similar in dysplasias and early cancers (30% vs. 35%). Loss of p16INK4 and p27KIP1 expression was less frequent in dysplasias than in early cancers (p=0.005 and 0.001, respectively). Loss of Rb protein expression was not detected in dysplasia and rarely observed in early cancer (7%). The proliferation cell nuclear antigen index increased from moderate dysplasia to mucosal invasive carcinoma and was correlated significantly with the expression of cyclin D1, p16INK4 and p27KIP1 (p=0.0001, 0.003, and 0.007, respectively). Thus, this study found that cyclin D1 overexpression starts early in dysplasia and could be a useful marker for its malignant potentiality while reduction of p16INK4 and p27KIP1 occurs during the transformation from dysplasia to cancer. These findings suggest that esophageal dysplasia should be treated as a precancerous lesion.     

应用组织芯片检测食管鳞状细胞癌中APC、β-catenin、E-cadherin与cyclinD1的表达及其意义

背景与目的：食管鳞状细胞癌（esophageal squamous cell carcinoma,ESCC）的发生是个多因素多阶段的演进过程。Wnt信号转导通路在肿瘤发生发展中起重要作用。本研究探讨4种Wnt通路上的蛋白在食管鳞癌发生中的作用及在早期诊断中的意义。方法：制作由199例食管鳞癌组织与其癌旁164例正常粘膜、34例基底细胞增生和30例不典型增生上皮组成的组织芯片,应用免疫组化方法检测APC、 β-catenin、E-cadherin、cyclin D1的表达情况。结果：APC和E-cadherin在ESCC阳性率分别是69．6％、19．6％,均低于各自正常组（98．0％、96．3％,均为P〈0．01）, β-catenin和cyclin D1在ESCC的异常表达率分别是65．5％和70．9％,均高于各自正常组（1．2％,0．8％,均为P〈0．01）。按正常粘膜→基底细胞增生→不典型增生→ESCC的顺序,APC低表达发生在ESCC, β-catenin和E-cadherin表达异常始于不典型增生．cyclinD1过表达始于基底细胞增生。随着ESCC分化程度由高到低的改变,APC、E．cadherin和cyclinD1阳性率逐渐减少, β-catenin逐渐增加。 β-catenin的表达与APC无相关（r=-0．10,P〉0．05）,与E．cadherin呈负相关（r=-0．31,P〈0．01）,与cyclinD1呈正相关（r=0．49,P〈0．01）。结论：APC、E-cadherin、 β-catenin和cyclinD1可能在ESCC发生过程中起重要作用。 β-catenin、E-Cadherin和cyclinD1的表达检测有助于ESCC的早期诊断。     

Prognostic significance of biologic factors in squamous cell carcinoma of the esophagus.

BACKGROUND: Esophageal carcinoma is one of the most lethal tumors. Therefore, it is important to identify prognostic factors for patients with this disease. The objective of this study was to clarify the relation between clinicopathologic and biologic factors in esophageal carcinoma and to determine the prognostic significance of different biologic factors. METHODS: DNA ploidy pattern, Ki-67 labeling index (LI), and cyclin D1 and p53 protein expression were examined and detailed pathologic examinations were conducted on tumors from 53 patients (46 males and 7 females with a mean age of 66 years [range, 47-85 years]) with surgically resected esophageal squamous cell carcinoma and the prognostic value of these factors was evaluated. RESULTS: Of the 53 esophagus carcinomas examined, 26 (49%) were classified as DNA diploid. The mean Ki-67 LI was 45 +/- 4. 9% (range, 10.5-86.1%). p53 expression was detected in 38 of the carcinomas (71.7%) and cyclin D1 expression was detected in 35 (66%). Various prognostic factors were examined using the Cox stepwise regression model, four of which were found to correlate with overall survival: tumor size (P = 0.0346), lymph node status (P = 0.0384), Ki-67 LI (P = 0.0161), and p53 expression (P = 0.001). Lower Ki-67 LI and a lower rate of p53 expression were detected in the long term survival group (> 3 years) compared with the short term survival group (P = 0.00045 and P = 0.0023, respectively). CONCLUSIONS: The biologic factors of Ki-67 LI and p53 expression, as well as clinicopathologic factors, may be used as independent prognostic factors for patients with esophageal carcinoma. However, the results of the current study do not support cyclin D1 expression as a prognostic factor.     

Inactivation of DNA repair gene O6-methylguanine-DNA methyltransferase by promoter hypermethylation and its relation to p53 mutations in esophageal squamous cell carcinoma

The development of esophageal squamous cell carcinoma (ESCC) has been linked to exposure to carcinogens such as nitrosamines that cause various alkyl DNA damages and O6-methylguanine-DNA methyltransferase (MGMT) is a primary defence against alkylation-induced mutagenesis and carcinogenesis. This study was to investigate the role of inactivation of MGMT by promoter hypermethylation and its relation to p53 mutations in ESCC. Methylation of MGMT promoter was determined by methylation-specific polymerase chain reaction in 119 ESCC specimens, 22 corresponding tissue samples adjacent to the tumors, and 21 normal epithelial specimens of the esophagus. The levels of MGMT protein in ESCC with methylated or unmethylated MGMT were analyzed by quantitative immunohistochemistry. Mutations of p53 in 119 ESCC were detected by denaturing high-performance liquid chromatography and sequencing. We found that all 21 normal esophageal tissues had unmethylated MGMT; however, among 119 ESCC, 46 (38.7%) had hypermethylated MGMT. This epigenetic change also occurred in some normal tissues adjacent to the tumors. The level of MGMT protein in MGMT-methylated ESCC was significantly lower than that in MGMT-unmethylated ESCC, whereas great inter-individual variation and poor expression was also observed among MGMT-unmethylated ESCC. Fifty-one percent (61/119) ESCC showed p53 mutations but the distribution of the mutations did not differ significantly between MGMT-methylated ESCC (44%) and MGMT-unmethylated ESCC (56.2%; P = 0.18). MGMT promoter hypermethylation was neither associated with overall G:C to A:T mutations nor associated with this type of mutations in non-CpG dinucleotides in p53. Our results demonstrate that inactivation of MGMT by aberrant promoter methylation is a frequent molecular event in ESCC. This epigenetic alteration is an important, but may not be the sole, mechanism leading to the impaired expression of MGMT. Aberrant MGMT methylation seemed not to be associated with overall frequency and spectrum of p53 mutations in ESCC.     

P53 expression in esophageal dysplasia - a possible biomarker for carcinogenesis of esophageal squamous-cell carcinoma

The tumor suppressor gene product p53 has been detected in a high percentage of esophageal squamous cell carcinoma. To evaluate the role of this protein in carcinogenesis, we examined the p53 overexpression both in esophageal dysplasia and in esophageal squamous cell carcinoma in the same patients. Using anti-p53 antibodies pAb1801 and CM-1, we analyzed immunohistochemically 36 dysplastic lesions from 36 patients with esophageal cancer. Nuclear p53 was detected in 14 of 36 dysplasias (39%). From mild to moderate to severe dysplasia, p53 positivity showed tendency to increase in number. Seventeen of the 36 squamous cell carcinomas showed p53 expression (47%). There was a significant concurrent p53 expression in esophageal dysplasia and its related squamous cell carcinoma (p=0.00345). These results indicate that p53 mutation is closely associated with the initiation of this cancer.     

食管癌前细胞DNA含量及多基因表达的定量检测

目的 探讨食管癌高发区人群食管上皮癌变过程中的早期分子改变及早期癌变机理。方法 自食管癌高发区采集食管黏膜上皮细胞,碘化丙啶（propidium lodide,PI)染色进行DNA含量及倍体测定;对各基因蛋白进行间接免疫荧光标记,采用流式细胞仪（flow cytometry,FCM)进行定量检测。结果 DNA含量在癌形成时明显增高,二倍体细胞显著减少,而异倍体细胞明显增多,在癌细胞组异倍体率为84．2％;同时p53蛋白有明显积聚,而抑癌基因p16有明显缺失。在癌细胞组p53及cyclin D1蛋白表达的阳性率均为100％（5／5、6／6）。结论 在癌形成早期,DNA含量及异倍体率增加,癌基因cyclin D1表达增高,抑癌基因p16缺失及p53蛋白积聚。食管上皮癌形成时已有多个分子事件发生。     

Molecular biology of esophageal cancer

Squamous cell carcinoma (ESCC) is the most frequent histological subtype in esophageal cancer, although the incidence of esophageal adenocarcinoma (EAC) is increasing faster than any other malignancy in the western world. New developments in the understanding of molecular mechanisms in esophageal cancer comprise analysis of the genetic tumor profiles by CGH (comparative genomic hybridization), the detection of tumor suppressor gene inactivation, and the analysis of proto-oncogenes. Especially the inactivation of the p53 gene proved to be of particular importance for the development of esophageal cancer. Also p15 and p16 have been identified to be involved in the pathogenesis of esophageal cancer by influencing the cyclin kinase inhibitor cascade and DNA mismatch repair processes. Amplification of cyclin D1 results in growth advantage for tumor cells and enhances tumorigenesis; gene amplification and overexpression of cyclin D1 were frequently demonstrated especially in ESCC. Regarding the dysplasia-metaplasia-carcinoma sequence of Barrett's esophagus, inhibition of apoptosis by overexpression of bcl-2 proteins occurs as an early event.     

The expressions of p21 and pRB may be good indicators for the sensitivity of esophageal squamous cell cancers to CPT-11: Cell proliferation activity correlates with the effect of CPT-11

Previously, we demonstrated that CPT-11 is an effective agent against esophageal squamous cell cancers (ESCC), and that the protein level of DNA topoisomerase I can be a predictor for sensitivity to CPT-11 (Jpn J Cancer Res 2001; 92: 1335-41). Here, we describe our search for additional predictors of sensitivity to CPT-11, mainly among cell cycle-regulating proteins, because the cytotoxicity of CPT-11 is significantly correlated with the percentage of ESCC cells in S-phase. To this end, we selected and examined the expressions of 5 proteins involved in G1-S transition, i.e., p53, cyclin D1, p21, p27, and pRB, in 14 ESCC cell lines by western blot analysis. Among these proteins, the expression levels of p21 and pRB showed significant differences that were associated with the IC50 values for CPT-11 (P = 0.0339 and P = 0.0109, respectively). Namely, the expression of p21 or pRB independently could be a good indicator of CPT-11 efficacy in ESCC. In addition, the cell proliferation activities examined by enzyme-linked immunosorbent assay (ELISA) using 5-bromo-2'-deoxyuridine (BrdU) showed a significant correlation with the percentage of total S-phase cells (correlation coefficient = 0.568, P = 0.0324), and an inverse correlation with the IC50 values for CPT-11 (correlation coefficient =-0.601, P = 0.0213). Because, as in the case of DNA topoisomerase I, the cell proliferation activity determined using BrdU shows a close relationship with the MIB-1 labeling index, immunohistochemical studies of p21, pRB, and MIB-1 in resected ESCC specimens and/or biopsy samples could make it possible to predict more precisely the sensitivity of ESCC patients to CPT-11 prior to treatment.     

流式细胞术对食管癌组织中四种细胞周期调控蛋白的定量检测及意义

目的 探讨细胞周期调控蛋白cyclin E、cyclin D1、CDK4和D27在食管癌的表达及其与食管癌的分化和淋巴结转移的关系。方法 采用流式细胞术对65例食管鳞状细胞癌组织中cyclin E、cyclin D1、CDK4和p27的表达强弱进仃定量检测,结果 用荧光指数F1表示。结果 cyclin E、cyclin D1和CDK4在低分化型鳞癌的表达量显著高于分化型鳞癌(P值分别为0．0275,0．0001和0．0174);而p27在低分化型鳞癌的表达量显著低于分化型鳞癌(P=0．0042)。cyclin D1与cyolin E,cyclin D1与CDK4之间呈显著正相关;而cyclin D1与p27呈显著负相关。4种基因蛋白的表达与淋巴结转移均无相关性。结论 cyclhi E、cyclin D1、CDK4和p27的表达与食管癌的分化密切相关;正负性细胞周期调控蚩白表达的失衡是导致癌变的重要原因之一。     

食管癌组织中p16、p21、p53、cyclin D1表达及其意义

目的 探讨p16、p21、p53、cyclin D1在食管癌中的表达及其作用。方法 采用免疫组化方法检测30例食管癌中p16、p21、p53、cyclin D1的表达,采用PCR－SSCP的表达p53基因突变情况。结果 p16、p21阳性表达率均为63．3％,p53为66．7％,cyclin D1为86．7％,p53基因突变率为26．7％。结论 食管癌以p53第7外显子突变为主cyclin D1过度表达在食管中是常见的并且是早期出现的分子异常,p16、P21可作为判断食管癌分化程度及预后的1个参考指标。     

Expression of cyclin D1 and p53 and its correlation with proliferative activity in the spectrum of esophageal carcinomas induced after duodenal content reflux and 2,6-dimethylnitrosomorpholine administration in rats

Alterations in expression of the p53 and cyclin D1 genes have been implicated in the development of esophageal carcinomas in both humans and animal models. We hypothesize that altered expression of cyclin D1 and p53 may be involved in the sequential development of esophageal carcinomas with glandular differentiation induced by the carcinogen, 2,6-dimethylnitrosomorpholine (DMNM) in rats with duodenal content reflux esophagitis. In the present study Sprague-Dawley rats were given DMNM 15 days after performing an esophago-jejunostomy in order to induce chronic duodenal content reflux esophagitis. Expression and localization of p53, cyclin D1 and Ki-67 were examined by immunohistochemical analyses. Twenty of 24 animals developed different types of esophageal carcinomas, including pure squamous carcinoma, adenosquamous carcinoma and pure adenocarcinoma. Undifferentiated basaloid areas were frequently observed in these tumors. Cyclin D1 overexpression was observed in hyperplastic lesions and increased through dysplasia and in undifferentiated areas of infiltrating carcinoma. Cyclin D1 expression coincided with increased Ki-67 expression and decreased along with cell differentiation. The p53 immunohistochemical pattern was parallel to that of cyclin D1, although the percentage of positive cells was usually smaller in all lesions and increased p53 expression started at the dysplastic stage. These findings suggest that overexpression of cyclin D1 may be an early event in DMNM-induced rat esophageal tumorigenesis, causing increased proliferation of esophageal stem cells. Abnormal p53 expression may then be required to promote the development of neoplastic transformation from dysplastic epithelium through invasive phenotype, being more evident in cancer cells with squamous differentiation.     

Insufficient effect of p27(KIP1) to inhibit cyclin D1 in human esophageal cancer in vitro

The cell cycle is controlled by protein complexes composed of cyclins and cyclin-dependent kinases. p27KIP1 (p27) is one of the Kip/Cip family cyclin-dependent kinase inhibitory proteins which negatively regulate cell cycle progression, and have been proposed as candidate tumor suppressor genes. To examine the role of p27 in the development of human esophageal squamous cell carcinoma (ESCC), we performed Western blot and immunoprecipitation analyses of the levels of expression of p27 protein in a series of ESCC cell lines. This protein was expressed at various levels in these cell lines during exponential growth. p27 level was significantly associated with that of cyclin D1, but not of cyclin E. Further cell cycle synchronization studies demonstrated that p27 was free or bound with affinity to cyclin E-CDK2 more than to cyclin D1-CDK4 or cyclin D1-CDK6. It is known that overexpression of cyclin D1 rather than cyclin E is involved in the pathogenesis of ESCC. Our findings indicated that high expression of p27 throughout the G1 to S phase may inhibit more likely cyclin E, than cyclin D1, which promotes tumor growth of esophageal squamous cell carcinoma.     

维甲酸受体-β等肿瘤分子标志物在食管正常及异常组织中的表达及意义

目的 研究食管癌高发区人群的正常食管上皮、癌前病变及癌组织活检标本中,维甲酸受体-β(RAR-β)mRNA、p16、p53和Ki67蛋白的异常表达及其与食管癌发生的关系。方法 全组397例标本,其中食管正常黏膜组织25例,轻度不典型增生69例,中度不典型增生106例,重度不典型增生51例,原位癌78例,鳞状细胞癌68例。应用RNA原位杂交技术检测RAP-β mRNA的水平,应用免疫组织化学技术检测p16、p53和Ki67蛋白的表达情况。结果 在正常黏膜、轻度、中度、重度不典型增生、原位癌及鳞状细胞癌组织中,RAR-β mRNA表达检出率分别为96．0%、89．9%、67．9％、68．6％、62．8％和63．2％;p16表达检出率分别为88．0％、71．0％、64．2％、51．0%、53．8％和52．9%;p53异常表达检出率分别为4．0％、39．1％、57．5%、52．9％、67．9％和69．1％;Ki67异常表达检出率为0、40．6％、61．3％、58．8%、59．0％和75．0%。结论 4种肿瘤生物学标志物在食管上皮中、重度不典型增生和原位癌组织中的表达,未出现明显差异,而只表现为形态学上的差异。     

Topological analysis of p21WAF1/CIP1 expression in esophageal squamous dysplasia.

In the normal stratified squamous epithelium of the esophagus, only the third to the fifth layers of cells express the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21). Using immunohistochemical staining, we examined the topological distribution of cells expressing p21, p53, Ki67, and cytokeratin 10 (CK10), a differentiation marker of esophageal squamous cell carcinoma (SCC), in 25 superficial SCCs and 72 dysplastic lesions of the esophagus. Image analysis of p21, p53, and Ki67 expression was also performed in 48 dysplastic lesions. In superficial SCCs, although Ki67- and p53-expressing cells were mainly distributed in the deep layers of tumors despite tumor differentiation, the distribution of p21 correlated with tumor differentiation. In dysplastic lesions, p53- and Ki67-coexpressing cells tended to locate in the same layers and expand in the lower layers of epithelium with the progression of dysplasia. p21-expressing cells shifted to the upper layers of the epithelium with the progression of dysplasia. However, this change was heterogeneous; in some lesions, p21-expressing cells were confined to the superficial layers of atypical cells (confined type), whereas in others, p21-overexpressing cells were scattered among atypical cells (scattered type). CK10 expression was observed in 25% of dysplastic lesions, and the frequency of CK10 expression was significantly higher in the scattered than in the confined type. Our results suggest that esophageal squamous dysplasia represents the earliest pathological process in esophageal squamous carcinogenesis. Our results also suggest that differentiation of esophageal SCC is determined at the stage of dysplasia, and that p21 plays a critical role in the differentiation process.     

Evaluation of an indicator for lymph node metastasis of esophageal squamous cell carcinoma invading the submucosal layer.

Lymph node metastasis is a major prognostic factor for esophageal squamous cell carcinoma (ESCC). In recent years, endoscopic mucosal resection (EMR) has been developed with excellent results for the treatment of the superficial ESCC. To make the EMR treatment successful, it is important to establish a good indicator to identify ESCC patients at a high risk of lymph node metastasis. In this study, we examined clinicopathological and immunohistochemical factors to investigate the factors involved in lymph node metastasis of ESCC invading to the submucosal layer (sm-ESCC). Surgical specimens from 84 sm-ESCC patients were examined. Among 84 sm-ESCC patients, 33 (39.3%) had lymph node metastases. Clinicopathologically, tumor depth, lymphatic invasion and blood vessel invasion showed significant correlations with lymph node metastasis by univariate analysis. Tumor depth and lymphatic invasion showed significant correlations by multivariate analysis of these factors. Immunohistochemically, P53 accumulation was observed in 45 cases (53.6%), cyclin D1 overexpression in 25 (29.8%), and pRB in 65 (77.4%). P53 accumulation, cyclin D1 overexpression and MIB-1 Labeling Index were significantly associated with lymph node metastasis by univariate analysis, and P53 accumulation showed a significant correlation with lymph node metastasis by multivariate analysis. Among tumor depth, lymphatic invasion and P53 accumulation, tumor depth and lymphatic invasion were significantly correlated with lymph node metastasis (P = 0.0023 and P = 0.0092, respectively) by multivariate analysis. These data suggest that tumor depth and lymphatic invasion can be considered as good indicators for lymph node metastasis among patients with sm-ESCC. In addition, P53 accumulation could be helpful to identify the patients who need additional treatment after EMR.