Prognostic impact of p21/waf1/cip1 in colorectal cancer

In addition to the tumor suppressor gene p53, Cyclin Dependent Kinases (CDK) are well known to influence the cell cycle in normal human tissues and various neoplasias as well. The purpose of our present study was to evaluate the expression of the CDK-inhibitor p21/waf1/cip1 in colorectal cancer with special emphasis on the prognostic impact. Between 1985 and 1991, 294 patients (median age, 65 years) underwent surgical operative therapy for colorectal cancer. Formalin-fixed and paraffin-embedded tumor specimens were investigated. For immunohistochemistry the Catalysed Reporter Deposition (CARD) technique was performed. The survival probability was calculated and possible prognostic risk factors were tested using multivariate analysis. The p21/ waf1/cip1 staining pattern was positive in 197 (67%) specimens and negative in 97 (33%) samples. No significant correlation could been calculated between p21/waf1/cip1 expression and other variables such as age, sex, WHO-Classification, localisation, grading, TNM-classification or UICC-stage. Patients with a positive staining reaction had a significantly better survival (p < 0.0052). Moreover, p21/waf1/cip1 was shown to be an independent prognostic parameter by multivariate analysis (p < 0.022). In contrast with these findings, the p53 tumor status had no impact on survival. P21/ waf1/cip1 appears to be an independent prognostic parameter in colorectal cancer and is associated with a favorable survival. This feature may be related to a cell cycle arrest in the G1 phase induced by p21/waf1/cip1, resulting in lower tumor cell proliferative activity.     

Anti-sense oligonucleotide of p21(waf1/cip1) prevents interleukin 4-mediated elevation of p27(kip1) in low grade astrocytoma cells

Elevation of the cyclin-dependent kinase (cdk) inhibitor, p27(kip1) is necessary for Interleukin (IL)-4-mediated growth arrest of human low grade astrocytoma (RTLGA) cells and occurs at 24 h of treatment. Pathways involved in IL4 alteration of p27(kip1) are unknown, however. Here we investigated whether other cdk inhibitors contributed to the actions of IL-4 on RTLGA cells. By 12 h of IL-4 treatment, both cdk4 and cdk2 kinase activities against the retinoblastoma protein (pRb) were reduced and nuclear entry of pRb was prohibited. Twelve-hour cdk complexes contained elevated p21(waf1/cip1) but not p27(kip1), p15(ink4B) or p16(ink4A). IL-4 increased p21(waf1/cip1) but not p27(kip1) mRNA levels, and stimulated luciferase activity of a p21(waf1/cip1) promoter-luciferase reporter. In p53-mutant WITG3 cells, IL-4 did not alter p21(waf1/cip1) mRNA and promoter-luciferase activity or p27(kipl) protein, suggesting a need for functional p53. STAT6 phosphorylation by IL-4, however, occurred in both p53-mutant WITG3 and p53-functional RTLGA cells. Pre-treatment of RTLGA with anti-sense but not missense p21(waf1/cip1) oligonucleotide prior to IL-4: (a) restored cdk activities; (b) reduced cdk4-associated p21(waf1/cip1) levels; (c) prevented p27(kipl) elevation; and (d) reversed growth arrest. These results are the first to suggest that p21(waf1/cip1) is essential for IL-4-mediated elevation of p27(kip) and growth arrest of astrocytoma cells.     

Expression of cyclins A and D and p21(waf1/cip1) proteins in renal cell cancer and their relation to clinicopathological variables and patient survival.

We have studied 118 renal cell carcinomas to analyse the expressions of cyclins A and D1 and p21(waf1/cip1), and their relationship to clinical and histopathological parameters as well as to clinical outcome. Cyclins A and D1 and cyclin-dependent kinase inhibitor p21 (waf1/cip1) were not expressed in normal renal tissue. Staining signals of cyclin D1 and p21(waf1/cip1) were always nuclear but cyclin A was also expressed in the cytoplasm of the tumour cells. The mean (range) fractions of cyclin A, cyclin D1 and p21(waf1/cip1)-positive tumour cells were 2.2% (range 0-20%), 23.3% (range 0-90%) and 6.8% (range 0-70%) respectively. The expression of cyclin A was related to venous invasion, high nuclear grade, high mitotic rate, high Ki-67 and high PCNA expressions (P < or = 0.006 for all). The expression of cyclin D1 was linked with age over 65 years, low nuclear grade and high p53 expression (P < or = 0.05 for all). An inverse correlation was present between p21(waf1/cip1) and cyclin D1 (P = 0.011). Cyclin A predicted survival in the entire study group (P = 0.0014), in T1-4/N0-2/M0 (P = 0.0007) and in T1-2/N0/M0 tumours (P = 0.0007). Cyclin A was also a powerful predictor of disease-free survival in T1-4/N0/M0 (P = 0.0027) tumours (P = 0.0007). Cyclin D1 and p21(waf1/cip1) were not significantly related to survival or disease-free survival in any of the groups. In the entire material the independent prognostic factors were the presence of distant metastases (relative risk (RR) 5.16, P < 0.001), T category (RR 2.68, P < 0.001), Ki-67 expression (RR 1.02, P = 0.026) and cyclin A expression (RR 1.12, P = 0.001). The independent predictors in T1-4/N0/M0 tumours were T-category (RR 2.67, P = 0.001) and cyclin A (RR 1.21, P < 0.001), and in T1-2/N0/M0 tumours the only significant predictor was cyclin A (RR 1.19, P = 0.0002). In renal cell carcinoma, cyclin A is a powerful and independent prognostic factor in all clinical stages of the disease, whereas cyclin D1 and p21(waf1/cip1) have no prognostic value.     

The prognostic significance of p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67 proteins expression in gastric cancer: a clinicopathological and immunohistochemical study of 121 Arab patients

BACKGROUND: The variability of prognosis within a pathological stage of gastric cancer (GC) at presentation, underscores the need for specific biological markers to identify subgroups of patients with aggressive course for intensive treatment. To our knowledge, this is the first study from an Arab population reporting on the relationship of p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67 expression, and clinicopathological features and their prognostic significance. METHODS: Formalin-fixed paraffin-embedded tumors were studied by immunohistochemistry, using monoclonal antibodies to p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67. The results were correlated with clinicopathological features and survival. RESULTS: M:F = 80:41; median age = 60 years; stage III and IV = 71%; and median follow-up = 34.4 months. Positive expression rates of p53, p27 kip1, p21 waf1, Ki67, and HER-2/neu were 54%, 40%, 8.3%, 70%, and 12% respectively. p53 expression correlated with age <60 years (P = 0.03), tumor size >5 cm (P = 0.01), p27 kip1 and Ki67 expression (P = 0.0001), and HER-2/neu (P = 0.04). p21 waf1 correlated inversely with T-stage (P = 0.008) and Her-2/neu expression correlated with histological grade (P = 0.04) and T-stage (P = 0.008). Univariate analysis showed that p53 overexpression (P = 0.01), fungating and infiltrative macroscopic appearance (P = 0.02), size >5 cm (P = 0.0001), lymph node metastasis (P = 0.0001), p T3 and T4 disease (P = 0.01), and overall stage III and IV (P = 0.0001) disease were adverse prognostic factors. Patients with tumor profiles p53 (-)/p27 (+) had better survival than those with p53 (+)/p27 kip1 (-)(P = 0.02). On multivariate analysis by Cox regression model, the expression of p53 (P = 0.03) and lymph node involvement (P = 0.01) were significant adverse prognostic factors for overall survival. CONCLUSIONS: The expression of p53 in Arab patients with GC correlates with aggressive tumor characteristics and is an independent prognostic factor. The combined analysis of p53 and p27 kip1 is of added prognostic value.     

Prognostic significance of p27/kip1 and apoptosis in patients with colorectal carcinoma

The protein p27/kip1 is a cyclin-dependent kinase inhibitor that regulates cell-cycle progression. In the present study, p27/kip1 expression as well as tumor cell proliferation and apoptosis were investigated in 80 colorectal carcinomas, using anti-p27/kip1 antibodies, in situ apoptosis detection kits and anti-PCNA antibodies. Immunohistochemical staining indicated that p27/kip1 was localized heterogeneously in the nuclei of cancer cells. The frequency of samples positive for p27/kip1 was 53.8% (43/80). There was no significant correlation between p27/kip1 status and clinicopathologic factors. Mean apoptotic index (AI) in p27/kip1-positive patients (3.22+/-1.65) was significantly higher than in p27/kip1-negative patients (2.46+/-1.44; p=0.033). No correlation was observed between p27/kip1 expression and the PCNA labeling index (PCNA-LI) (p=0.47). Overall survival was significantly longer for patients who were p27/kip1-positive (80.7%) compared to those who were negative (49.3%; p=0.0003). Univariate analysis revealed no significant differences between prognosis and AI or PCNA-LI. In multivariate analysis, p27/kip1 expression was found to be an independent prognostic marker (p=0.015). In conclusion, the present study shows that p27/kip1 is a potentially important prognostic and predictive marker for outcome in colorectal carcinoma. These results might be explained by the role of p27/kip1 in promoting apoptosis.     

Expression of p21<Superscript>waf1/cip1</Superscript>, p27<Superscript>kip1</Superscript>, p63 and Androgen Receptor in Low and High Gleason Score Prostate Cancer

The aim of this study was to investigate the expression of p21^waf1/cip1, p27^kip1, p63 and androgen receptor proteins in relation to serum prostate specific antigen levels in low and high Gleason score prostate cancers. Biopsies of patients suffering from prostate adenocarcinoma of low (3 + 3 to 3 + 4) and high (5 + 4 to 5 + 5) Gleason scores (13 cases each group) were immunostained for positive regulators of cell cycle control (p21^waf1/cip1 and p27^kip1), and essential markers of normal prostate gland ontogeny (p63) and growth (androgen receptor) to find differentially expressed markers of malignant progression. Serum prostate specific antigen levels were also monitored at the time of biopsy and following anti-androgen therapy. All cases except one in each group were androgen receptor positive. P63 and p21^waf1/cip1 proteins detected in normal basal cell nuclei were lost in all but one studied tumors respectively. P27^kip1 protein, however, was detected in all low Gleason score prostate cancers, but it was found in only 7/13 high score cases. Prostate specific antigen levels, either pre- or post-treatment, did not show strict correlation with the p27^kip1 results. The low to high grade dedifferentiation of prostate adenocarcinoma is accompanied with the down-regulation of p27^kip1 protein, which may be an important molecular sign of the lost cell cycle control.     

Immunohistochemical study of cell cycle-associated proteins in adenocarcinoma of the uterine cervix treated with radiotherapy alone: P53 status has a strong impact on prognosis

PURPOSE: Because the incidence of adenocarcinoma of the uterine cervix has recently risen, the evaluation of radiotherapy (RT) for this disease has become an increasingly urgent matter. We analyzed the expression of the cell cycle-associated proteins p53, p27, p21/waf1/cip1, and cyclin D1 in cervical adenocarcinomas in correlation with the prognostic significance in tumors treated with RT alone. METHODS AND MATERIALS: The expression of p53, p27, p21/waf1/cip1, and cyclin D1 was studied using an immunohistochemical method in 53 cases of cervical adenocarcinoma treated only with RT. Patients received RT alone between 1965 and 1994. The mean patient age was 61.8 +/- 12.6 years (range, 36-82 years). The number of patients with Stage I, II, III, and IVA disease was 6, 16, 28, and 3, respectively. RESULTS: The number of patients with p53, p27, p21/waf1/cip1, and cyclin D1 positive tumors was 24, 18, 22, and 8, respectively; no statistically significant correlation was noted. The 5-year disease-free survival rate of p53-positive patients was 30%, significantly lower than the 62% for the p53-negative patients (p = 0.02); no statistically significant correlation was noted between disease-free survival and p27, p21/waf1/cip1, and cyclin D1 expression. No statistically significant correlation was observed between local control and expression of any of the proteins. CONCLUSION: Expression of p53 protein has a statistically significant impact on disease-free survival in adenocarcinoma of the uterine cervix treated with RT alone. However, the clinical significance of p27, p21/waf1/cip1, and cyclin D1 protein expression was not obvious.     

Additive effects of tamoxifen and the farnesyl transferase inhibitor FTI-277 on inhibition of MCF-7 breast cancer cell-cycle progression

The efficacy of tamoxifen in the hormonal therapy of breast cancer is well established, but therapeutic resistance is inevitable. FTIs are a new class of anticancer drugs that are in phase III clinical evaluation. Since the mechanisms of action of these 2 classes of drugs are different, we tested the combination of tamoxifen and FTI-277 on inhibiting proliferation of hormone-dependent MCF-7 human breast cancer cells. An additive effect on cell proliferation was demonstrated, accompanied by an additive G(0)/G(1) arrest. The major effect of the combination of the 2 drugs was to maintain p21(waf/cip1) at an intermediate level, higher than that observed in the presence of tamoxifen alone. This was associated with an additive effect on inactivation of cyclin E-Cdk2 complexes and decreased phosphorylation of pRb and p130 pocket proteins. These effects were accompanied by increased association of 2 CDIs, p27(kip1) and p21(waf/cip1), with cyclin E-Cdk2 complexes. These data demonstrate that the additive effect is likely predominantly due to the recruitment of p27(kip1) and, to a lesser extent, p21(waf/cip1) into the cyclin E-Cdk2 complexes. Together, these results suggest that the combination of FTI and tamoxifen may increase the antitumor effect of either drug alone in breast cancer.     

p21cip1和p27kip1基因遗传多态与食管癌及贲门癌发病风险的关联

背景与目的：有研究表明p21^cip1和p27^kip1的基因多态性与乳腺癌、肺癌、前列腺癌等肿瘤易感性有关。本研究分析中国北方高发区人群食管鳞状细胞癌（ESCC）和贲门腺癌（GCA）与勺p21^cip1和p27^kip1基因多态性之间的关系。方法：应用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）方法检测299例ESCC患者、256例GCA患者及437名健康对照人群p21^cip1 3’非翻译区和p27^kip1第109位密码子基因多态性分布情况。结果：ESCC患者组p21^cip1 T等位基因型频率（42．8％）显著高于健康对照组（36．7％）（P=0．02）,ESCC和GCA患者组p27^kip1等位基因型频率（分别为96．8％和96．1％）均显著高于健康对照组（92．9％）（P值分别为0．00和0．02）。ESCC患者组p21^cip1基因型频率分布与健康对照组相比有显著性差异（P=0．04）,与C／C和C／T基因型相比,T／T基因型可显著增加ESCC的发病风险（校正OR=1．93,95％CI=1．12～3．94）ESCC和GCA患者细p27^kip1基因型频率分布与健康对照组相比均有显著性差异（P分别为0．00和0．01）,与V／G和G／G基因型相比,V／V基因型可显著增加ESCC和GCA的发病风险（校正OR分别为2．44和2．01,95％CI分别为1．2l～4．02和1.12～3．68）。当按吸烟和上消化道肿瘤家族史状况进行分层分析时发现,与V／G和G／G基因型相比,V／V基因型可显著增加吸烟人群患ESCC和GCA（校正OR分别为2．24和2．61,95％C1分别为1.14～4．03和1．25～3．82）以及有家族史人群患ESCC的发病风险（校正OR=2．04,95%CI=1．04～3．43）．两基因联合分析显示,携带p21^cip1T／T和p27^kip1V／V基因型可显著增加患食管癌和贲门癌的发病风险（校正OR分别为3．78和2．56,95?分别为1．46～5．89和1．06～4．78）。结论：在中国北方人群中,p21^cip1基因多态性可能与食管癌的易感性有关,p27^kip1基因多态性可能与食管癌和贲门癌的易感性有关．而且这两个基因的多念性可能存食管癌和贲门癌发病中起联合作用．     

Effects of p21cip1/waf1 overexpression on growth, apoptosis and differentiation in human colon carcinoma cells

The cyclin-dependent kinase inhibitor p21cip1/waf1 negatively regulates the progression of cell cycle and the potential usefulness of p21cip1/waf1 gene is proposed in gene therapy. However, studies have demonstrated a protective role of p21cip1/waf1 against apoptosis and little is known about effects of ectopic expression of p21cip1/waf1 on differentiation of colon cancer cells. In the present study, we found diffuse p21cip1/waf1 expression in only a few clinical samples of colorectal cancer with wild-type p53 gene. To explore the role of p21cip1/waf1 in cell growth, apoptosis and differentiation, we constitutively overexpressed p21cip1/waf1 in HT29 colon carcinoma cells. Ectopic overexpression of p21cip1/waf1 was associated with inhibition of CDK2-associated kinase activity, indicating the functionality of the introduced p21cip1/waf1 gene. Overexpression of p21cip1/waf1 caused an appreciable growth inhibition in monolayer and soft agar cultures and it significantly reduced sodium butyrate- but not 5-fluorouracil-induced apoptosis. p21cip1/waf1 overexpressing cells exhibited marked decrease of intestinal differentiation when assayed with intestinal alkaline phosphatase. Our findings suggest that introduction of p21cip1/waf1 gene into colon cancer cells may be useful for inhibiting cell growth but caution should be taken regarding the increased resistance to certain apoptosis-inducing agents and dysregulation of endogenous p21cip1/waf1-mediated differentiation process.     

Expression of p53 and p21waf1/cip1 in gastric carcinoma: lack of inter-relationship or correlation with prognosis.

AIMS: The cell cycle regulators p53 and p21waf1/cip1 are expressed variably in human cancers. We investigated their expression in gastric carcinoma and determined their inter-relationship and prognostic significance. METHODS: Immunohistochemistry was used to determine their expression in material from 100 resected specimens of gastric carcinoma, and comparison was then made of the degree of expression between each, with conventional clinicopathological indices and with survival. RESULTS: Positivity was found with p53 (40%) and p21 (75%). There was no significant correlation between the expression of each individual marker, nor between each marker and 5-year survival. There appeared to be an association between p53 expression and lymph node metastases, and a higher frequency of p21waf1/cip1 expression in males. CONCLUSIONS: The expression of p53 and p21waf1/cip1 as detected by immunohistochemistry were of no value in predicting the prognosis of patients with gastric carcinoma.     

Low expression of p27(Kip1), a cyclin-dependent kinase inhibitor, is a marker of poor prognosis in synovial sarcoma

BACKGROUND: Low expression of p27(kip1), a dominant cyclin-dependent kinase inhibitor involved in G1-S transition of the cell cycle, recently has been reported to be associated with aggressive tumor growth. It has been shown that active cell proliferation alludes to poor prognosis in patients with synovial sarcoma. However, to the authors' knowledge, little is known about the clinicopathologic significance of p27(kip1) in synovial sarcoma. METHODS: p27(kip1) expression was examined immunohistochemically in 55 cases of primary synovial sarcoma, and the relations between p27(kip1) expression and several cell proliferation markers, i.e., mitotic index (MI), Ki-67 labeling index (Ki-67 LI), and clinicopathologic parameters related to poor prognosis, were determined. Univariate and multivariate survival analyses were performed to evaluate the prognostic significance of p27(kip1) expression in synovial sarcomas. RESULTS: p27(kip1) labeling index (p27(kip1) LI) correlated inversely with MI (r = -0.44, P = 0.0007) and Ki-67 LI (r = -0.63, P < 0.0001). Of the clinicopathologic parameters examined, tumor necrosis (P = 0.019) and American Joint Committee on Cancer (AJCC) stage (P = 0.021) correlated significantly with p27(kip1) LI. Survival analysis showed that p27(kip1) LI was an independent prognostic factor for overall survival in patients with synovial sarcoma (P = 0.0031). CONCLUSIONS: The study results suggested that low expression of p27(kip1) may be useful as a marker of poor-prognosis synovial sarcoma.     

槲皮素通过调控p21/cip1和p27/kip1蛋白的稳定性抑制口腔鳞状细胞癌细胞增殖

目的:探究槲皮素通过调控p21/cip1和p27/kip1蛋白的稳定性对口腔鳞状细胞癌细胞增殖的影响.方法:CCK-8试剂盒检测口腔鳞状细胞癌细胞(SCC-15)增殖情况;流式细胞术检测SCC-15细胞周期分布;Western blot检测CyclinD1/CDK复合体、p21/cip1、p27/kip1、p-GSK3...     

非小细胞肺癌组织中Skp2的表达及其与p27kip1和Ki-67蛋白表达的关系

目的:探讨Skp2的表达在非小细胞肺癌(nonsmallcelllungcancer,NSCLC)发生发展中的作用,及其与p27kip1和Ki67蛋白表达的关系。方法:应用免疫组化SP法检测Skp2、p27kip1和Ki67三种蛋白在60例NSCLC和20例正常支气管黏膜上皮组织中的表达。结果:NSCLC组织中Skp2蛋白表达的阳性率为48.33%(29/60),显著高于正常支气管黏膜上皮组织中的表达,P=0.000。Skp2的表达与肿瘤的组织学类型、肿瘤细胞的分化程度、TNM分期、淋巴结转移和患者吸烟与否显著相关,P值分别为0.038、0.005、0.019、0.010和0.002,但与患者的年龄及性别无关,P值分别为0.833和0.281。NSCLC组织中Skp2表达与p27kip1表达呈显著负相关,P=0.001;而与Ki67表达呈显著正相关,P=0.027。结论:Skp2在NSCLC组织中表达是上调的,可能是通过作用于细胞周期调控蛋白p27kip1,加速了对p27kip1泛素化依赖的蛋白降解,使其表达及代谢发生异常,导致细胞周期失控并促进细胞异常增殖,从而参与了NSCLC的发生和发展。     

肾母细胞瘤MIB-1（Ki-67增殖指数）和p27kip1表达及与预后的关系

目的:探讨肾母细胞瘤MIB-1（Ki-67增殖指数）和细胞周期蛋白依赖性激酶抑制剂p27kip1的表达及与预后的关系。方法:经医院伦理委员会批准,连续纳入2008年1月至2013年8月在我院就诊的肾母细胞瘤患者样本作为研究对象,观察p27kip1和MIB-1阳性表达与患者临床特征的关系。结果:肿瘤组织中MIB-1阳性表达率高于正常肾组织,p27kip1阳性表达率低于正常肾组织,差异均有统计学意义（P＜0.05）。MIB-1和p27kip1表达与性别、年龄、病理分型、发病部位等均无相关性（P＞0.05）,与临床分期存在相关性（P＜0.05）。MIB-1表达阳性患者中位生存时间低于阴性患者,而p27kip1表达阴性患者中位生存时间低于阳性患者（χ2=6.979、15.247,P=0.008、0.000）。结论:MIB-1表达增加和p27kip1表达降低与肾母细胞瘤的发生、发展、预后密切相关,临床应根据其表达情况进行针对性干预,以改善患者的预后。     

Expression of cell-cycle-regulated proteins pRb2/p130, p107, p27(kip1), p53, mdm-2, and Ki-67 (MIB-1) in prostatic gland adenocarcinoma.

PURPOSE: The quest for prognostic molecular markers in prostatic carcinoma is still in progress. Many proteins have already been screened by immunohistochemistry with the aim to find the most reliable indicator of progressive disease. In this study, we evaluated the expression of pRb2/p130, p107, p27(kip1), p53, mdm-2, and Ki-67 (MIB-1) by immunohistochemistry in 24 prostate carcinomas compared with the paired expression of normal prostates. EXPERIMENTAL DESIGN: Expression of the different proteins in normal and pathological specimens was evaluated by the Wilcoxon test. A matrix of correlation (Spearman coefficient) was used to evaluate the possible association in expression among the different proteins. Logistic regression analysis was used to test the multivariable prognostic value of the levels of protein expression for the probability of disease development. RESULTS: p53 and Ki-67 (MIB-1) showed a higher expression in cancer than in normal tissue (P = 0.006 and <0.001, respectively). pRb2/p130, p107, and p27(kip1) showed an overall lower expression in cancer, but the difference between cytoplasmic and nuclear expression was always higher for cancer (Ps, from <0.001 to 0.016). mdm-2 expression was lower in cancer, but the difference between cytoplasmic and nuclear expression was not significant (P = 0.571) when compared with that in normal tissue. A positive correlation between p27 and pRb2/p130 levels expressed, in normal and cancer counterparts in the same sample, as the difference between cytoplasmic and nuclear protein concentrations (P = 0.045) was found. Additionally, p107 expression showed an inverse correlation with Ki-67 (MIB-1) expression in the most aggressive tumors (P = 0.046). Logistic regression output showed that Ki-67 (MIB-1) and pRb2/p130 (expressed as differences between cytoplasmic and nuclear concentrations) were the variables associated with a higher risk of cancer. The highest value was reported for Ki-67 (MIB-1) (odds ratio, 2.11), followed by pRb2/p130 (odds ratio, 1.01). pRb2/p130 alone was associated with a sensitivity (rate of cases having a posterior probability of disease >/=0.5) of 61% with a false positive rate of 22%. Ki-67 (MIB-1) alone yielded a sensitivity of 69% and a false positive rate of 14%. The combined model (Ki-67 + pRb2/p130) yielded a sensitivity of 83% with a false positive rate of 17%. Interestingly, one specimen in which we also found a high-grade prostatic intraepithelial neoplasia showed the progressive loss of pRb2/p130 from normal prostatic cells to prostatic intraepithelial neoplasia cells, suggesting that in prostatic cancer, lack of expression of the tumor suppressor gene pRb2/p130 could be involved in the progression of the disease, from an early stage. CONCLUSIONS: This study showed that all of the proteins but mdm-2 were expressed at a different rate in normal and pathological prostate specimens. Multivariate analysis showed that pRb2/p130 and p107 may be involved in the pathogenesis and progression of prostate cancers, and that the expression of the retinoblastoma-related protein pRb2/p130 along with Ki-67 (MIB-1), expressed as differences between cytoplasmic and nuclear concentrations, could be considered new parameters to be evaluated in discriminating patients at a higher risk for prostate cancer.     

Cyclooxygenase-2 promotes human cholangiocarcinoma growth: evidence for cyclooxygenase-2-independent mechanism in celecoxib-mediated induction of p21waf1/cip1 and p27kip1 and cell cycle arrest

The expression of cyclooxygenase-2 (COX-2) is increased in human cholangiocarcinoma. However, the biologic function and molecular mechanisms of COX-2 in the control of cholangiocarcinoma cell growth have not been well established. This study was designed to examine the direct effect of COX-2 and its inhibitor celecoxib on the growth of human intrahepatic cholangiocarcinoma cells. Overexpression of COX-2 or treatment with prostaglandin E(2) (PGE(2)) enhanced human cholangiocarcinoma cell growth, whereas antisense depletion of COX-2 in these cells decreased PGE(2) production and inhibited growth. These findings demonstrate a direct role of COX-2-mediated PGE(2) in the growth regulation of human cholangiocarcinoma cells. Furthermore, the COX-2 inhibitor celecoxib induced a dose-dependent inhibition of cell growth, cell cycle arrest at the G(1)-S checkpoint, and induction of cyclin-dependent kinase inhibitors p21(waf1/cip1) and p27(kip1). However, the high concentration of celecoxib (50 micro M) required for inhibition of growth, the incomplete protection of celecoxib-induced inhibition of cell growth by PGE(2) or COX-2 overexpression, and the fact that overexpression or antisense depletion of COX-2 failed to alter the level of p21(waf1/cip1) and p27(kip1) indicate the existence of a COX-2-independent mechanism in celecoxib-induced inhibition of cholangiocarcinoma cell growth.