Nucleostemin knocking-down causes cell cycle arrest and apoptosis in human T-cell acute lymphoblastic leukemia MOLT-4 cells via p53 and p21Waf1/Cip1 up-regulation

Objectives

Nucleostemin (NS), a recently discovered nucleolar protein, is essential for maintaining self-renewal and proliferation of embryonic and adult stem cells as well as cancerous cells. The aim of this study was to determine biological function of NS in MOLT-4 cells as a human T-cell acute lymphocytic leukemia (T-ALL) model.

Methods

Efficacy of a specific small interference RNA on NS depletion was studied by quantitative polymerase chain reaction and western blotting. The growth rate and viability were analyzed by trypan blue exclusion test. Fluorescent microscopy was used for detecting apoptosis. Cell cycle and apoptosis were mechanistically studied by flow cytometry and western blotting.

Results

Knockdown of NS inhibited proliferation, arrested the cell cycle, and induced apoptosis through p53 and p21^Waf1/Cip1 pathways in MOLT-4 cells.

Discussion

These findings demonstrate critical roles of NS in MOLT-4 cells and may implicate on its therapeutic potential in this human T-ALL model.     

Role of p53 and p21/WAF1 detection in patient selection for preoperative radiotherapy in rectal cancer patients

BACKGROUND: Recent studies showed that p53 and p21 may play major roles in determining tumor radiosensitivity through the apoptosis pathway. The aim of this study was to investigate the predicting value of radiosensitivity in human rectal carcinoma. METHODS: p53 and p21/WAF1 expressions in formalin fixed, paraffin-embedded, preradiation biopsy samples from 49 patients with primary rectal carcinoma were analyzed immunohistochemically. p53 and p21 expressions and their relationships with histopathologic changes after radiation and other clinical features were evaluated. RESULTS: Expressions of p53 and p21/WAF1 were 49 and 28.6 percent, respectively. In 36.7 percent of total tumors, significant histopathologic effect can be observed. There was a significant inverse expression of p53 and p21. Most of the p53(+) or p21(–) tumors were radioresistant, and the majority of p53(–) or p21(+) tumors were radiosensitive. Tumors size in the radiosensitive, p53(–), or p21(+) group decreased more significantly than in radioresistant, p53(+), or p21(–) group (P<0.01), and patients with radioresistant, p53(+), or p21(–) tumors had more local recurrence, more distant metastasis, and a shorter five-year survival rate than those with radiosensitive, p53(–), or p21(+) tumors, but without statistic significance. No statistically significant correlation can be observed between other tumor clinical features and radiosensitivity, p53, or p21 expressions. CONCLUSION: Immunohistochemistry detection of p53 and p21 expressions may be useful parameters for more radiosensitive patients selected for preoperative radiotherapy.Supported by a Grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.Presented at the meeting of the Asian-Pacific Congress of Gastroenterology, Yokohama, Japan, September 19 to 23, 1996.     

p21WAF1基因对人食管鳞癌细胞增殖的抑制作用

目的:探讨p21WAF1( p21)基因转染对食管鳞癌细胞系EC109细胞增殖的影响.方法:根据转染质粒的不同和是否进行质粒转染分为3组.p21转染组:用脂质体Lipofectamine2000介导将pCDNA3.1(+)- p21质粒转染入EC109细胞; 空载体转染组:同样方法将pCDNA3.1(+)-neo质粒转染入EC109细胞; 未转染组:未转染的EC109细胞.应用RTPCR、Western blot分别检测p21基因mRNA、P21蛋白变化; 流式细胞仪分析细胞周期变化,应用MTT、流式细胞仪和透射电镜检测转染外源p21基因对EC109细胞增殖和凋亡的影响.结果:p21转染细胞中p21 mRNA和P21蛋白高表达; p21转染组EC109细胞生长速度低于空载体组和未转染组; 流式细胞仪观察到P21蛋白高表达使EC109细胞发生G1/S阻滞,G1期细胞比例显著高于空载体组和未转染组(63.120%±2.893% vs 41.380%±6.536%,42.173%±5.301%,均P<0.01),S期比例显著低于空载体组和未转染组(18.923%±3.084%vs 22.573%±5.463%,26.867%±2.922%,均P<0.01),并出现亚G1峰(凋亡峰).透射电镜亦发现p21转染组发生细胞凋亡.结论:p21基因转染可以抑制人食管鳞癌细胞系EC109细胞增殖并能诱导其发生细胞凋亡.     

结直肠癌中CDX2、p21~(H-ras)、p21~(WAF1)表达的临床意义

背景:CDX2与肠源性肿瘤的发生密切相关,而p21表达减低或缺失可能是结直肠癌发生、发展中的一个普遍事件。目的:探讨结直肠癌中CDX2、p21~(H-ras)、p21~(WAF1)表达的相关性和临床病理意义。方法:收集45例临床病理资料完整的结直肠癌手术切除标本,以免疫组化方法检测癌组织和相应癌旁组织中的CDX2、p21~(H-ras)、p21~(WAF1)蛋白表达。结果:结直肠癌组织中CDX2、p21~(H-ras)、p21~(WAF1)阳性率分别为86.7%、68.9%和35.6%,相应癌旁组织中阳性率分别为100.0%、37.8%和51.1%,CDX2和p21~(H-ras)在癌组织和癌旁组织中的阳性率差异有统计学意义(P=0.026和P=0.006);半定量分析结果显示CDX2和p21~(WAF1)在癌组织和癌旁组织中的表达水平差异有统计学意义(P=0.007和P=0.005)。癌组织中CDX2与p21~(H-ras)的表达存在相关性(r_s=0.501,P=0.000)。Dukes A、B期患者癌组织p21~(WAF1)阳性率显著高于C、D期患者(P=0.016),有淋巴结转移者p21~(WAF1)阳性率显著低于无淋巴结转移者(P=0.048),CDX2、p21~(H-ras)的表达与结直肠癌各临床病理特征均无相关性。结论:CDX2、p21~(H-ras)、p21~(WAF1)表达改变可能与结直肠癌的发生、发展相关。     

肝胆管癌丙型肝炎病毒感染与p53和p21WAFD/CIP1异常表达的关系

为探讨丙型肝炎病毒（ＨＣＶ）感染与Ｐ５３和Ｐ２１ＴＷＡＦ－／ＣＩＰ１基因的关系。采用 化技术对２９例原发性肝胆管癌中ＨＣＶ抗原（ＮＳ５－Ａｇ）、ｐ５３和ｐ２１＾ＷＡＦＩ＝／ＣＩＰ１蛋白表达进行研究。结果：２９例胆管癌中ＮＳ５－Ａｇ、ｐ５３及Ｐ２１ＴＷＡＦＩ／ＣＩＰＩ蛋白表达进行研究。结果：２９例胆管癌中ＮＳ５－Ａｇ、Ｐ５３display structure     

p21WAF1/CIP1 基因转染对胃癌细胞生物学活性的影响

目的探讨p21^WAF1／CIP1基因(p21基因)对人胃癌细胞系(BGC)生物学活性的影响。方法应用分子克隆技术构建p21^WAF1／CIP1基因真核表达载体，然后用脂质体法将其导入到人胃癌细胞BGC中，经G418筛选获得可稳定表达p21^WAF1／CIP1的人胃癌细胞克隆，用中性红摄入法观察细胞生长速率，流式细胞仪(FcM)检测细胞周期变化。结果p21导入胃癌BGC细胞后，肿瘤细胞增值能力明显受到抑制，并出现细胞周期G1期阻滞。结论p21基因具有抑制胃癌细胞增殖的作用，可作为胃癌基因治疗的靶基因．     

Distinct patterns of apoptosis in association with modulation of CD44 induced by thrombopoietin and granulocyte-colony stimulating factor during ex vivo expansion of human cord blood CD34+ cells

The insufficient number of haemopoietic stem cells (HSCs) in cord blood (CB) is the major potential limitation to widespread use of CB for marrow replacement. Cytokine-mediated ex vivo expansion has been proposed as a means of increasing the number of CB HSCs for transplantation. However, the biology of CB HSCs during cytokine-mediated ex vivo expansion, such as apoptosis or expression of adhesion molecules, has not yet been elucidated. We have investigated the patterns of apoptosis and CD44 expression on human CB CD34+ cells during ex vivo expansion. CD34+ cells isolated from human CB were cultured in a stroma-free liquid culture system with thrombopoietin (TPO), flt3-ligand (FL), stem cell factor (SCF), and/or granulocyte-colony stimulating factor (G-CSF). During the culture, for up to 5 weeks, apoptosis was measured by staining with 7-amino-actinomycin D (7-AAD) along with concurrent immunophenotyping of CD34 and CD44 with three-colour flow cytometry. In the cultures with TPO, an apoptotic fraction with down-regulated CD44 appeared from the fourth day up to the second week. G-CSF also induced apoptosis but in a different manner; the apoptotic fraction without down-regulation of CD44 appeared unremittingly for up to 5 weeks. FL did not induce apoptosis or down-regulation of CD44. These findings show that apoptosis is indeed involved in the regulation of CB CD34+ cells in ex vivo expansion and the patterns of apoptosis are dependent on the type of cytokines used. The distinct patterns of apoptosis suggest different mechanisms of TPO and G-CSF in inducing apoptosis, which still remains to be elucidated.     

Transcriptional upregulation of p21/WAF/Cip1 in myeloid leukemic blasts expressing AML1-ETO

An inducible model for conditional expression of AML1-ETO in myeloid U-937 cells was generated previously to determine cellular effects of AML1-ETO and to identify target genes. Induction of AML1-ETO expression in U-937 resulted in reduced cell growth, G1 arrest and apoptosis. Microarray analysis showed more genes up-regulated than down-regulated (180 vs. 69). Clustering of AML1-ETO-positive and -negative cell lines was possible based on these differentially expressed genes. p21/WAF/Cip1 (CDKN1A) was up-regulated 4.6-fold upon induction of AML1-ETO which was confirmed in additional experiments. Knock-down of AML1-ETO by siRNA could reduce p21/WAF/Cip1 expression in Kasumi-1 cells. mRNA expression analysis of p21/WAF/Cip1 in a large cohort of acute myeloid leukemia patients demonstrated a significantly higher expression in AML1-ETO-positive leukemia. The increased expression of p21/WAF/Cip1 in primary leukemic blasts suggests that elevated p21/WAF/Cip1 levels may contribute to specific features observed in AML1-ETO positive leukemia.     

Estrogen stimulates expression of p21Waf1/Cip1 in mouse uterine luminal epithelium

p21^Waf1/Cip1 was originally identified as an inhibitor of the cell cycle. Recent evidence suggests that it can act as a positive regulator of the cell cycle under the influence of some growth stimulators. We investigated the effects of ovarian steroids on the expression of p21, DNA synthesis, and mitosis in the uterus. Capsules containing 17β-estradiol (E₂) were subcutaneously implanted in ovariectomized mice that were sacrificed on different days. Their uteri were collected for p21 immunohistochemical staining. To study mitosis and DNA synthesis, colchicine and bromodeoxyuridine (BrdU) were injected into mice 3 or 5 h before sacrifice. The results showed that p21 expression, BrdU incorporation, and the mitotic index in uterine luminal epithelium increased 1 to 2 d after E₂ stimulation and then declined to basal levels between d 3 and 6. Furthermore, cotreatment with progesterone (P₄) and E₂ suppressed both p21 expression and the DNA synthesis stimulated by E₂ alone in uterine epithelial cells. Our results show that estrogen stimulates p21 expression and cell proliferation in uterine luminal epithelium and that cotreatment with P₄ prevents both effects, suggesting that p21 may act as a positive cell-cycle regulator.     

Polysaccharide-K (PSK) increases p21WAF/Cip1 and promotes apoptosis in pancreatic cancer cells

BackgroundPolysaccharide-K (PSK, Krestin^®) is a natural remedy and one of the most commonly used medicinal mushroom extracts. It has been used as oral adjuvant treatment in cancer therapy in Japan and other Asian countries for more than 40 years. PSK is thought to be an immune modulator, however, its antitumor actions remain undefined. The aim of the present study was to investigate underlying mechanisms by which PSK exerts its antitumor effects on malignant epithelial cells.MethodsAntitumor activities of PSK were evaluated on multiple human pancreatic adenocarcinoma cells in vitro. Cell viability, apoptotic pathways, cytokine expression and involvement of TLR2 and TLR4 were monitored by MTT, flow cytometry, Western blotting and protein arrays.ResultsWe demonstrate that PSK acts as a growth inhibitor for pancreatic cancer cells, known otherwise to be highly resistant to conventional chemotherapies. Pancreatic cancer cells can be protected against PSK-mediated growth inhibition by neutralizing antibodies against TLR2 and TLR4. The antiproliferative actions were associated with upregulated cell cycle regulatory p21^WAF/Cip1 and pro-apoptotic protein Bax levels, resulting in cell cycle arrest and induction of apoptosis. In addition, a significant growth inhibition and additive effect was observed with PSK and gemcitabine administered as combined treatment.ConclusionWhile previous studies have emphasized the potential importance of PSK in immune activation, the present results uncover additional mechanisms on epithelial cells that may contribute to the antitumor effects provided by PSK as suggested by clinical observations.     

Expression of p21Waf1/Cip1 predicts response and survival of esophageal cancer patients treated by chemoradiotherapy

Chemoradiotherapy is a multimodal therapy routinely used as a primary treatment for advanced esophageal cancer. However, it is beneficial only to patients who respond. To identify pretreatment markers predicting response and survival, we examined the expression of cell cycle regulatory molecules, p53, p21(Waf1/Cip1) cyclin D1, and CDC25B, in biopsy specimens from 76 patients with stage III and stage IV squamous cell carcinoma. Overexpression of p53, p21, cyclin D1 and CDC25B was observed in 58%, 30%, 28%, and 32% of patients, respectively. The expression of p21 correlated significantly with response to chemoradiotherapy (P = 0.0001). Survival of patients with p21-expressing tumors was better than that of patients with p21-negative tumors (P = 0.013). Expression of other genes was not significantly correlated with treatment response and survival. In patients with p53-negative tumors, survival of those patients with p21-positive tumors was significantly higher than that of those with p21-negative tumors (P = 0.0452), but no significant difference was found in patients with p53-positive tumors. Multivariate analysis revealed that p21 expression was an independent variable among pretreatment parameters in predicting survival. These results suggest that p21 expression is potentially useful for predicting the response to chemoradiotherapy and survival of patients with advanced esophageal squamous cell cancer.     

Histone deacetylase inhibitors induce caspase-dependent apoptosis and downregulation of daxx in acute promyelocytic leukaemia with t(15;17)

Histone deacetylase (HDAC) appears to play an important role in the pathogenesis of acute promyelocytic leukaemia (APL) as it is recruited by both PML-RARalpha and PLZF/RAR alpha in leukaemic cells with t(15;17) and t(11;17) respectively. Recent studies have demonstrated that HDAC inhibitors can be therapeutically used in various neoplastic disorders including APL. Cell differentiation was considered the major mechanism of the anti-leukaemic effects of HDAC inhibitors in APL. However, most of these studies either evaluated the effect of HDAC inhibitors in combination with all-trans retinoic acid (ATRA) or focused on the less common form of APL with t(11;17). To investigate the cellular effects of HDAC inhibitors, including sodium butyrate, trichostatin A, and suberoylanilide hydroxamic acid (SAHA), we used two APL cell lines, NB4 and the ATRA-resistant derivative NB4.306. Moreover, primary cells from five patients with cytogenetic evidence for t(15;17) were also studied. Our results demonstrated that HDAC inhibitors induce distinct caspase-dependent apoptosis in APL, which showed both concentration-and time-dependence. In addition, changes in the apoptosis-regulatory proteins, daxx, bcl-2 and bax were analysed. HDAC inhibitors induced downregulation of daxx, but no significant changes were detected in bcl-2 or bax. In conclusion, apoptosis induced by HDAC inhibitors in APL could provide an effective strategy for treatment of patients with t(15;17).     

Oncogenic ras induces premature senescence in endothelial cells: role of p21(Cip1/Waf1)

Recent studies have shown that the presence of tumor suppressors such as p53 or p16 account for the lack of transformation in primary cells. To investigate a potential role of active Ras in atherosclerosis, we infected bovine aortic endothelial cells with a replication-deficient, recombinant adenovirus containing the activated H-Ras^61L gene. Ras overexpression led after 72 hours to G1- and G2/M-cell cycle arrest due to induction of p21^Cip1/Waf1. Treatment of Ras-infected endothelial cells with 40 ng/ml TNF-α for 20 hours augmented apoptosis 8-fold in comparison to Ad-Con (control virus with empty expression cassette) infected cells (36.2 % vs. 4.3 %, p < 0.001), while Ras itself did not cause any cell death. Furthermore, more than 58 % of Ras-infected cells stained positive for senescence-associated β-galactosidase activity as opposed to 2 % in control vector-infected cells (p < 0.001), strongly suggesting a senescent phenotype in the Ras-infected population. We found further features of senescence in Ras-transduced endothelial cells, such as growth arrest and the lack of AP-1 serum inducibility. Finally, we evaluated the role of p21^Cip1/Waf1 in this process of senescence. Adenoviral overexpression of p21 led to growth arrest by induction of G1- and G2/M-cell cycle arrest. In addition, p21-overexpressing endothelial cells were highly sensitive for TNF-α induced-apoptosis. Surprisingly, senescence-associated β-galactosidase activity was not apparant in p21-infected endothelial cells, suggesting further signaling events necessary for the senescent morphology of endothelial cells. Our results demonstrate a novel way to render primary endothelial cells senescent by overexpressing oncogenic Ras. Increased sensitivity of senescent endothelial cells for cytotoxic stimuli seemed to be due to Ras-induced upregulation of p21^Cip1/Waf1. Future studies have to investigate a potential role of Ras in human vascular biology. Received: 5 June 2001, Returned for revision: 28 June 2001, Revision received: 6 July 2001, Accepted: 31 July 2001     

KLF6、p21^WAF1/CIP1、CyclinD1在结直肠癌中的表达及意义

目的研究转录因子KLF6、p21WAF1/C IP1及Cyc linD1在结直肠癌中的表达及意义。方法应用免疫组化Envision法对58例结直肠癌组织、20例结直肠黏膜慢性炎症组织中的KLF6、p21WAF1/C IP1及Cyc linD1蛋白表达进行检测。结果结直肠癌组织KLF6、p21WAF1/C IP1及Cyc linD1蛋白表达率均与结直肠黏膜慢性炎症组织比较有统计学差异（P〈0.05）;KLF6、p21WAF1/C IP1及Cyc linD1蛋白在结直肠癌组织中的表达与其浸润深度及预后有关（P〈0.05）。结论 KLF6、p21WAF1/C IP1及Cyc linD1在结直肠癌的发生发展中可能起重要作用。     

p21~(WAF1/CIP1/SDI1)在大鼠肾脏组织的增龄性变化及意义

目的 研究p21野生型p53活化片段1/细胞周期蛋白依赖性激酶影响蛋白1/衰老细胞衍生抑制剂1(p21WAF1/CIP1/SDI1)在大鼠肾脏中随年龄增长的表达变化规律. 方法 取3月龄、12月龄及24月龄健康雄性Wistar大鼠肾组织进行衰老相关β-半乳糖苷酶(SA-β-gal)活性染色,TUNEL法检测细胞凋亡,采用逆转录多聚酶链反应(RT-PCR)和Western印迹法(Western blot assay)分别在基因及蛋白质表达水平上检测肾脏组织中p21WAF1/CIP1/SDI1的表达变化,并用免疫组化法检测p21WAF1/CIP1/SDI1在肾脏组织中的表达与定位. 结果 大鼠肾脏组织SA-β-gal活性随年龄增长逐渐增强,凋亡细胞也随年龄增长逐渐增加(P＜0.05);p21WAF1/CIP1/SDI1 mRNA表达随年龄增长逐渐增强,不同月龄比较差异有统计学意义(P＜0.05).Western印迹亦显示p21WAF1/CIP1/SDI1蛋白表达随鼠龄增加逐渐增强(P＜0.05).免疫组化结果显示,p21WAF1/CIP1/SDI1蛋白表达于大鼠肾小球足细胞,其在肾小管与间质细胞中也有表达,且随年龄增长表达增加(P＜0.05). 结论 p21WAF1/CIP1/SDI1在大鼠肾脏组织中的表达随年龄增加而增强,可作为肾脏组织中重要的衰老指标.     

大肠小扁平腺瘤、息肉样腺瘤p53、p21表达的研究

目的:观察大肠小扁平腺瘤p53、p21基因的表达,探讨小扁平腺瘤与息肉样腺瘤生物学行为的不同及其与大肠癌的关系.方法:利用免疫组化法研究50例小扁平腺瘤(A组)和30例息肉样腺瘤(B组)以及20例正常大肠黏膜(C组)的p53、P21基因表达情况.结果:p53、p21 在A、B、C 三组中阳性率分别为58%、56%;33.3%、36.7%;5%、10%.P53阳性率三组间差异有显著性(P＜0.05).p21阳性率:A、B组分别与C组有差异显著性(P＜0.05);A组高于B组,但卡方检验P＞0.05,无统汁学差异;A组进一步与B组中直径＜1.0cm的腺瘤的p21阳性率(30%)比较,差异有显著性(P＜0.05).结论:大肠小扁平腺瘤p53、p21基因的异常表达提示小扁平腺瘤的生物学行为与息肉样腺瘤有差别,可能更易于恶变.     

Differentiation of functional dendritic cells and macrophages from human peripheral blood monocyte precursors is dependent on expression of p21 (WAF1/CIP1) and requires iron

Summary. Iron is required for monocyte/macrophage differentiation of HL‐60 leukaemia cells. Differentiation requires induction of the cyclin‐dependent kinase inhibitor p21 (WAF1/CIP1), and cell cycle arrest at the G1/S checkpoint. With iron depletion, p21 induction and differentiation are blocked. To establish the roles of iron and p21 in normal monocyte/macrophage differentiation, we examined generation of dendritic cells (DCs) and macrophages from peripheral monocytes. Monocytes were cultured with interleukin 4 and granulocyte–macrophage colony‐stimulating factor (GM‐CSF), then treated with lipopolysaccharide to produce DCs or with M‐CSF to produce macrophages. Iron deprivation was induced by desferrioxamine (DF). Monocyte‐derived DCs had characteristic phenotype and morphology, and stimulated proliferation of naïve allogeneic T lymphocytes. In contrast, DCs generated under iron deprivation were phenotypically undifferentiated and did not stimulate T cells. Similarly, macrophages expressed a characteristic phenotype and morphology, and phagocytosed latex beads, but macrophages generated under iron deprivation failed to develop a mature phenotype and had impaired phagocytosis. Iron deprivation blocked induction of p21 (WAF1/CIP1) expression in both DC and macrophage cultures. Furthermore, p21 antisense oligonucleotides, but not sense oligonucleotides, inhibited both DC and macrophage differentiation. These data indicate that a key role of iron in haematopoiesis is to support induction of p21 which, in turn, is required for DC and macrophage differentiation.     

Expression of p53 and p21WAF1/CIP1 Proteins in Gastric and Esophageal Cancers (Comparison with Mutations of the p53 Gene)

The p53 gene has been shown to be commonlymutated in various human cancers, and mutant p53 can actas a dominant oncogene. The intact p53 protein is alsoknown to induce the cyclin-dependent kinase inhibitor p21^WAF1/CIP1 and is implicated incell cycle arrest. We investigated p53 gene alterationsin gastric adenocarcinoma and esophageal squamous cellcarcinoma to elucidate the association of the nuclearaccumulation of the p53 protein and/orp21^WAF1/CIP1 protein. Abnormalities of thetumor suppressor gene p53 protein and the expression ofp21^WAF1/CIP1 protein were analyzed byimmunohistochemical techniques in 32 cases of gastric adenocarcinoma and 15 cases ofesophageal squamous cell carcinoma. Twenty cases ofgastric cancer and five cases of esophageal cancer werealso analyzed for p53 gene mutation by polymerase chain reaction and direct nucleotide sequencing.Overexpression of p53 protein was found in 13/32 (41%)of gastric cancers and 5/15 (33%) of esophageal cancers.We found immunodetectable p53 in 10/14 cases with mutations and in none of 11 cases withoutmutations in gastric and esophageal cancers. Hence,immunohistochemical and genetic analyses gave concordantresults in 84% of 25 cases, revealing a good correlation between immunostaining of p53 and missensemutation of the p53 gene. p53 immunostaining was notobserved in cases with frameshift or splicing mutation.The expression of p21^WAF1/CIP1 protein wasfound in 9/32 (29%) of gastric cancers and 4/15 (27%) ofesophageal cancers and in 2/14 (14%) cases withalteration of the p53 gene and in 5/11 (45%) without.These results suggest that abnormalities of p53 may be closely associated with the pathogenesisof gastric adenocarcinoma and esophageal squamous cellcarcinoma and that the immunoreactivity of p53 proteinis a general indicator of the tumors with altered p53 function. The expression ofp21^WAF1/CIP1 protein was suppressed in theneoplastic tissues with and without p53 genealteration.