Rho和ROCK蛋白在上皮性卵巢癌中的表达及临床意义

目的探讨上皮性卵巢癌Rho和ROCK蛋白的表达及其与上皮性卵巢癌进展之间的关系。方法应用Western blot方法,观察了66例上皮性卵巢癌和22例正常卵巢组织Rho和ROCK蛋白的表达,并分析Rho/ROCK蛋白表达与生存期的关系。结果RhoA、C和ROCK蛋白在卵巢癌组织中表达增加,且在伴有肿瘤转移的淋巴组织中表达高于没有肿瘤转移的淋巴组织(P<0.05)。RhoA、C和ROCK间的表达呈正相关(P<0.05),RhoA、C和ROCK的表达与肿瘤分化、淋巴转移和短综合生存期相关(P<0.05)。多变量分析显示,只有RhoC是影响生存的独立因素(P<0.05)。RhoA和C是影响综合生存期的因素(P<0.05)。结论在上皮性卵巢癌中,RhoA、C和ROCK蛋白高表达,Rho/ROCK通路可能参与了上皮性卵巢癌的进展。     

Overexpression of RhoA, Rac1, and Cdc42 GTPases is associated with progression in testicular cancer.

The Rho family of GTPases are involved in actin cytoskeleton organization and associated with carcinogenesis and progression of human cancers. We investigated the roles of Rho family GTPases, prototypes RhoA, Rac1, and Cdc42, and the major downstream targets of RhoA, ROCK-I, and ROCK-II in testicular cancer. We quantified protein expression in paired tumor and nontumor samples from surgical specimens from 57 consecutive patients with testicular germ cell tumors using Western blotting. Protein expression of RhoA, ROCK-I, ROCK-II, Rac1, and Cdc42 was significantly higher in tumor tissue than in nontumor tissue (P < 0.0001). Expression of protein for RhoA, ROCK-I, ROCK-II, Rac1, and Cdc42 was greater in tumors of higher stages than lower stages (P < 0.0001, P < 0.001, P < 0.001, P < 0.0001, P < 0.0001, respectively). Within stage II nonseminoma (31 patients), protein levels of RhoA, ROCK-I, ROCK-II, Rac1, and Cdc42 in the primary tumor were lower in the group of 24 patients with no evidence of disease after therapy compared with 7 patients with disease that was refractory/recurrent (P < 0.05). Rho family GTPases may be involved in the progression of testicular germ cell tumors.     

High expression of Ran GTPase is associated with local invasion and metastasis of human clear cell renal cell carcinoma

The Ran small GTPase (Ran) is involved in the regulation of nuclear transport, microtubule nucleation and dynamics, and spindle assembly. To address the question of whether Ran protein is associated with the progression of renal cell carcinoma (RCC), we compared by Western blotting the Ran protein levels in surgical RCC specimens from 180 consecutive Japanese patients with those in the corresponding nontumor tissue from the same patient. We also examined the Ran protein levels in tumors of different grades and stages. Ran proteins were more abundant in RCC tumor tissues than in nontumor tissues (p < 0.0001). High Ran expression was associated with higher grade, local invasion, and metastasis (p < 0.0001). Kaplan-Meier plots linked high Ran protein expression to a shorter overall survival in all cases (p < 0.0001) and a shorter disease-free survival in those without metastasis at radical or partial nephrectomy (M0; 131 cases, p < 0.0001). Ran protein expression was an independent factor influencing overall survival univariate analysis (p < 0.0001) and disease-free survival by multivariate analysis (p < 0.05). Our findings suggest that Ran is associated with the progression of RCC.     

Conditional ROCK activation in vivo induces tumor cell dissemination and angiogenesis

Progression of tumors to invasive and metastatic forms requires that tumor cells undergo dramatic morphologic changes, a process regulated by Rho GTPases. Elevated expression of RhoA and RhoC, as well as the Rho effector proteins ROCK I and ROCK II, are commonly observed in human cancers and are often associated with more invasive and metastatic phenotypes. To examine how ROCK contributes to the progression of solid tumors, we established a conditionally activated form of ROCK II by fusing the kinase domain to the estrogen receptor hormone-binding domain (ROCK:ER). ROCK:ER-expressing colon carcinoma cells grown as tumors in immunocompromised nude mice organized into discrete clusters surrounding blood vessels. However, ROCK:ER activation resulted in the aggressive dissemination of tumor cells into the surrounding stroma, indicating that increased ROCK signaling is sufficient to promote invasion from solid tumors. In addition, tumors in which ROCK:ER was activated were more highly vascularized, indicating that ROCK contributes to tumor angiogenesis. ROCK:ER activation resulted in changes to epithelial morphology and organization that facilitated motility in vitro, likely by inducing the redistribution of proteins such as ezrin, as well as adherens junction and extracellular matrix-binding proteins. These results suggest that ROCK inhibitors would be useful antimetastatic and antiangiogenic chemotherapeutic agents in tumors associated with elevated RhoA, RhoC, ROCK I, or ROCK II expression.     

人脑星形细胞瘤进展过程中Rho／ROCK信号通路的可能作用

目的探讨不同病理学级别人脑星形细胞瘤中Rho／ROCK信号通路可能扮演的角色。方法应用免疫组化法检测60例不同病理级别人脑星形细胞瘤组织中RhoA、RhoB、ROCK-1及ROCK-2蛋白表达,评估Rho/ROCK信号通路中RhoA、RhoB、ROCK-1及ROCK-2蛋白表达与星形细胞瘤的病理分级及临床特征的关系。结果（1）RhoA蛋白在瘤旁脑组织表达的阳性率为0,在低级别和高级别星形细胞瘤中表达的阳性率分别为20％和80％,高表达率分别为10．0％和66．7％;高级别组的阳性率和高表达率均高于瘤旁脑组织和低级别组（P〈0．05）;RhoA表达的强弱在一定程度上反映了人脑星形细胞瘤的恶性程度;（2）RhoA蛋白表达在〉40岁组的阳性率和高表达率均显著高于〈40岁组,两者差别均有统计学意义（P〈0．05）;（3）RhoA在右大脑半球组的高表达率显著高于左大脑半球组,差别有统计学意义（P〈0．05）;（4）RhoA蛋白表达的阳性率和高表达率与性别及肿瘤长径无关（P〉0．05）;（5）RhoB、ROCK-1及ROCK-2蛋白均为阴性表达。结论Rho/ROCK信号通路在人脑星形细胞瘤中的作用可能与RhoA／ROCK1,2及RhoB／ROCK1,2通路关系不大;RhoA在了解星形细胞瘤的发生、进展和寻找治疗新靶点方面有一定参考价值。     

RhoC基因的过量表达与肝细胞癌的侵袭转移

目的　研究探讨RhoC基因mRNA和蛋白的过量表达与肝细胞癌 (HCC)的发生发展和侵袭转移的关系。方法　采用逆转录聚合酶链反应 (RT PCR)和Western印迹法 ,检测 2 5例HCC及其癌旁肝组织、4例门静脉主干癌栓或肝外转移灶中RhoCmRNA和蛋白的表达 ;同时采用PCR产物单链构象多态性 (PCR SSCP)银染法检测RhoC基因的突变情况。结果　HCC组织和癌旁肝组织中均可检测到RhoC基因mRNA和蛋白的表达 ,RhoCmRNA在HCC组织中的表达较癌旁肝组织高 ,其吸光度(A)比值分别为 1.8± 1.1和 1.0± 0 .7,差异有显著性 (P <0 .0 1) ;RhoC蛋白在HCC组织中的表达同样高于癌旁肝组织 ,其A比值分别为 33992± 10 384和 17342± 9998,差异有显著性 (P <0 .0 1)。 4例门静脉主干癌栓或肝外转移灶中的RhoC基因mRNA和蛋白的表达量分别为 3.3± 0 .5和 6 386 5±9116 ,较HCC肝内病灶高 ,差异有显著性 (P <0 .0 1) ;RhoCmRNA和蛋白在分化较差、结节数较多、有静脉浸润或伴有肝外转移灶的HCC中过量表达 (P <0 .0 5 )。全部HCC经PCR SSCP银染法分析均未发现异常泳动条带。结论　RhoC基因的过量表达与HCC的发生发展和侵袭转移密切相关 ,且可能是通过过量表达而非突变发挥作用。     

Decreasing of p27(Kip1)and cyclin E protein levels is associated with progression from superficial into invasive bladder cancer

The p27(Kip1)(p27) protein is a cyclin-dependent kinase inhibitor of the transition from G1 to S phase. It has been reported that decreased p27 protein level is a negative prognostic indicator in human tumours including bladder cancer. We studied the relationship between protein levels of p27, cyclin E and Ki-67 and clinicopathological features of 145 consecutive Japanese patients with transitional cell carcinoma of the bladder using immunohistochemical staining. Low protein levels of p27 were associated with low staining of cyclin E (P = 0.0302), high Ki-67 index (P = 0.0306), poorly differentiated grade (P = 0.0006), muscle invasion (P = 0.0019) and lymph node metastsis (P = 0.0002). Low staining of cyclin E and high Ki-67 index correlated with poorly differentiated grade, muscle invasion and lymph node metastsis. Cyclin E protein levels was inversely related with Ki-67 index (P = 0.0002). Kaplan-Meier plots of survival rate in patients with low versus high p27 staining showed that low protein levels of p27 were associated with a shortened disease-free and overall survival (P< 0.0001 and P< 0.0001, respectively). Similarly, low staining of cyclin E and high Ki-67 index correlated with a shortened disease-free and overall survival. On multivariate analysis using Cox proportional hazards model, low protein levels of p27 and high Ki-67 index were independent predictors of shortened disease-free (P< 0.0001, P = 0.0031, respectively), and low protein levels of p27, low staining of cyclin E and high Ki-67 index of overall survival (P = 0.0017, P = 0.0009, P = 0.0003, respectively). In superficial bladder tumours (Ta, T1; 86 patients), significant correlations were observed between low p27 staining and high Ki-67 index and early recurrence (P = 0.0048, P = 0.0178, respectively). Among the recurrenced superficial tumours (35 patients), the tumours which remained at a low stage showed high protein levels of p27 and cyclin E, and the tumours which progressed to invasive disease showed a gradual decrease in p27 and cyclin E protein levels over time. Our findings suggest that decreased protein levels of p27 and cyclin E play a role in the progression of bladder cancer and to evaluate these protein levels may be useful in management of the diseases.     

Rho signaling, ROCK and mDia1, in transformation, metastasis and invasion

The Rho subgroup of the Rho GTPases consisting of RhoA, RhoB and RhoC induces a specific type of actin cytoskeleton and carry out a variety of functions in the cell. mDia and ROCK are downstream effectors of Rho mediating Rho action on the actin cytoskeleton; mDia produces actin filaments by nucleation and polymerization and ROCK activate myosin to cross-link them for induction of actomyosin bundles and contractility. mDia is potentially linked to Rac activation and membrane ruffle formation through c-Src-induced phosphorylation of focal adhesion proteins, and ROCK antagonizes this mDia action. Thus, cell morphogenesis, adhesion, and motility can be determined by the balance between mDia and ROCK activities. Though they are not oncogenes by themselves, overexpression of RhoA and RhoC are often found in clinical cancers, and RhoC has been repeatedly identified as a gene associated with metastasis. The Rho-ROCK pathway is implicated in Ras-mediated transformation, the amoeboid movement of tumor cells in the three-dimensional matrix, and transmigration of tumor cells through the mesothelial monolayer. On the other hand, the Rho-mDia1 pathway is implicated in Src-mediated remodeling of focal adhesions and migration of tumor cells. There is also an indication that the Rho pathway other than ROCK is involved in Src-mediated induction of podosome and regulation of matrix metalloproteases. Thus, Rho mediates various phenotypes of malignant transformation by Ras and Src through its effectors, ROCK and mDia.     

Frameshift mutations in the MBD4/MED1 gene in primary gastric cancer with high-frequency microsatellite instability

Prognostic value of p27(Kip1) immunohistochemical expression was evaluated in a series of 95 bladder carcinomas. Low p27(Kip1) expression was correlated with higher tumor grade (P=0.01) and stage (P=0.009), associated with poor overall survival (P=0.01) and, for superficial cancers, with disease-free survival (P=0.05). Thirty-five cases exhibited a heterogeneous expression related in some instances to tumoral architecture. Seventeen cases showed a cytoplasmic reactivity related to low nuclear expression (P=0.057). Loss of p27(Kip1) expression is a pejorative event in bladder tumors and inhibition of p27(Kip1) degradation could offer new therapeutic ways.     

Expression of valosin-containing protein in colorectal carcinomas as a predictor for disease recurrence and prognosis.

PURPOSE: Valosin-containing protein (VCP or p97) is associated with antiapoptotic function and metastasis via activation of the nuclear factor-kappaB signaling pathway. The present study was designed to investigate the prognostic significance of VCP expression in colorectal adenocarcinoma. EXPERIMENTAL DESIGN: We analyzed VCP expression immunohistochemically in 129 patients with colorectal carcinoma ages 35-84 years. The staining intensity of tumor cells was categorized as either weaker-to-equal (low VCP expression) or stronger (high expression) than that in noncancerous colonic mucosa. We also analyzed 8 colorectal adenomas and 10 metastatic foci. RESULTS: Low VCP expression was noted in 41 (31.8%) cases and high expression in 88 (68.2%) cases. A low level of VCP expression was noted in all adenomas, whereas a high level was seen in all metastatic tumors. A significant difference was observed in depth of invasion (T(1-2) versus T(3-4), P < 0.05), presence or absence of venous invasion (P < 0.05), and tumor stage (I and II versus III and IV; P < 0.05) between adenocarcinomas with low and high VCP expression. Patients with high VCP-expressing tumors had a higher recurrence rate (P < 0.001) and poorer disease-free and overall survival (P < 0.01 and P < 0.05, respectively) compared with the low expression group. Multivariate analysis revealed VCP expression level to be an independent prognosticator for both disease-free and overall survival. VCP level was an indicator of disease-free survival in both stage II and III (pathological Tumor-Node-Metastasis classification, P < 0.05 and <0.01, respectively). CONCLUSIONS: A high expression level of VCP in tumors is a poor prognostic marker in patients with colorectal carcinomas.     

RhoA and RhoC proteins promote both cell proliferation and cell invasion of human oesophageal squamous cell carcinoma cell lines in vitro and in vivo

There is growing evidence that Rho proteins are deregulated by overexpression in tumours; and according to some reports, this correlates with disease progression. Our previous clinical study had demonstrated a correlation between RhoA expression and tumour progression in oesophageal squamous cell carcinoma (ESCC). These findings prompted us to study, using nude mice, pathological roles of Rho proteins in human ESCC cells. Western blot analysis in ESCC cell lines, in addition to cell proliferation and in vitro migration assays, were performed to observe the malignant potential of RhoA and RhoC in untransfected and transfected cells. Constitutively active RhoA, RhoC and dominant negative RhoA (dnRhoA) proteins were transfected to ESCC (TE-1 and TE-2) cells. The stably transfected cells were injected into nude mice, and the growth and metastasis of these cells to the lungs were analysed. Tumour tissues were then examined using immunohistochemical methods for proteins Ki-67 (MIB-1), FAK, MMP-1, MMP-9 and TIMP-3. Protein levels of RhoA and RhoC in ESCC cell lines were visualised by Western blotting, and showed highest expression in TE-2 cells. Results from the migration assay illustrated that both RhoA and RhoC play a role in migration of ESCC cells. In TE-2 transfected cells, RhoC showed greater migration compared to RhoA. By using an experimental metastasis model in nude mice, RhoA was found to promote more tumour growth than RhoC, whereas RhoC induced lung metastasis in comparison to RhoA. Ki-67 labelling index was used to evaluate the proliferation potential of tumour tissue inoculated from nude mice. In TE-2 cells RhoA gave a proliferation capacity of 24.8+/-0.5, which was significantly higher than those of TE-2 RhoC 10+/-0.4 (P<0.01). Strong immunoreactivity for FAK, MMP-1 and MMP-9 proteins was present in all tumour cells. By contrast, loss of TIMP-3 expression was observed in all tumour cells. In conclusion, our results indicate that pro-oncogenic Rho proteins are involved in promoting tumour growth, cell migration and metastasis in human ESCC cells in nude mice. The results from this study suggest that active Rho proteins may induce a transforming effect that leads to a malignant phenotype.     

Clinical significance of Rho GDP dissociation inhibitor 2 in colorectal carcinoma

Background  

Small GTPase proteins, including RhoA, RhoB, RhoC, Rac1, and cdc42, are important molecules for linking cell shape and cell-cycle progression because of their role in both cytoskeletal arrangements and mitogenic signaling. Over-expression of wild-type or constitutively active forms of RhoA has been shown to induce invasive behavior in non-invasive rat hepatoma cells in vitro. In addition, over-expression of RhoC has been found in melanoma cells with increasing metastatic activity as well as inflammatory breast cancer. These results indicate that overexpression of Rho proteins contributes to cancer cell invasion and metastasis. Rho GDP dissociation inhibitor 2 (RhoGDI2) was recently shown to act as a metastasis suppressor gene in bladder cancer. The purpose of this study was to clarify the clinical significance of this gene expression in patients with colorectal carcinoma.     

Loss of P27Kip1 expression correlates with tumor grade and with reduced disease-free survival in primary superficial bladder cancers.

p27Kip1 is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. We previously reported a deregulated expression of p27Kip1 in a series of human cancer cell lines and in primary breast and colon cancers. Moreover, p27Kip1 has been reported as an important prognostic factor in primary lung, breast, colon, and prostate cancers. In this study, we evaluated the prognostic value of p27Kip1 in a series of 96 superficial (pTa-1) human bladder carcinomas. High (>50% positive cells), moderate (25-50%), and low (<25%) p27Kip1 staining was observed in 39 (41%), 19 (20%), and 38 (39%) of the 96 primary superficial bladder cancers, respectively. No significant association was found between the expression level of p27Kip1 and tumor stage. Decreased p27Kip1 staining correlated with higher tumor grade (P = 0.001). Interestingly, a significant association was observed between increased expression of p27Kip1 and positivity for p53 (>20% positive cells; P < 0.001). A significant correlation was also observed between low expression of p27Kip1 and decreased disease-free survival (P = 0.0003 by log-rank test) and overall survival (P = 0.01 by log-rank test). Furthermore, on multivariate analysis, low p27Kip1 protein expression was an independent predictor of reduced disease-free survival (P = 0.018; relative risk = 1.95) second only to tumor stage. These data indicate that p27Kip1 protein is frequently expressed at low level in poorly differentiated tumors and suggest that this protein might represent a useful prognostic marker for disease recurrence and overall survival in superficial bladder carcinomas.     

Src and caveolin-1 reciprocally regulate metastasis via a common downstream signaling pathway in bladder cancer

In bladder cancer, increased caveolin-1 (Cav-1) expression and decreased Src expression and kinase activity correlate with tumor aggressiveness. Here, we investigate the clinical and functional significance, if any, of this reciprocal expression in bladder cancer metastasis. We evaluated the ability of tumor Cav-1 and Src RNA and protein expression to predict outcome following cystectomy in 257 patients enrolled in two independent clinical studies. In both, high Cav-1 and low Src levels were associated with metastasis development. We overexpressed or depleted Cav-1 and Src protein levels in UMUC-3 and RT4 human bladder cancer cells and evaluated the effect of this on actin stress fibers, migration using Transwells, and lung metastasis following tail vein inoculation. Cav-1 depletion or expression of active Src in metastatic UMUC-3 cells decreases actin stress fibers, cell migration, and metastasis, while Cav-1 overexpression or Src depletion increased the migration of nonmetastatic RT4 cells. Biochemical studies indicated that Cav-1 mediates these effects via its phosphorylated form (pY14), whereas Src effects are mediated through phosphorylation of p190RhoGAP and these pathways converge to reduce activity of RhoA, RhoC, and Rho effector ROCK1. Treatment with a ROCK inhibitor reduced UMUC-3 lung metastasis in vivo, phenocopying the effect of Cav-1 depletion or expression of active Src. Src suppresses whereas Cav-1 promotes metastasis of bladder cancer through a pharmacologically tractable common downstream signaling pathway. Clinical evaluation of personalized therapy to suppress metastasis development based on Cav-1 and Src profiles seems warranted.     

RhoA、RhoC及其效应分子ROCK-1的表达与卵巢癌细胞系恶性行为相关性的体外研究

目的　研究RhoA、RhoC及其效应分子ROCK 1在卵巢癌细胞中的表达水平 ,探讨其与卵巢癌转移的相关性。方法　逆转录聚合酶链反应 (RT PCR)检测RhoA、RhoC及ROCK 1在SW6 2 6、Skov 3、A2 780和Caov 34种卵巢癌细胞中mRNA的表达水平 ;Westernblot法检测RhoA和ROCK 1蛋白质的表达情况 ;Boyden小室体外侵袭试验测定 4种卵巢癌细胞的体外迁移与侵袭能力。结果　RhoA、RhoC和ROCK 1在 4种卵巢癌细胞中呈不同程度表达 ,其中仅RhoC的表达水平与癌细胞侵袭力和迁移能力呈正相关 (r=0 .95 ,P <0 .0 1)。RhoA在转录水平和蛋白水平中呈不同步变化 ,且RhoA和RhoC的表达与ROCK 1的表达无相关性。 4种卵巢癌细胞的体外侵袭和迁移能力相一致 ,其中SW6 2 6最强 ,Caov 3最弱 ,Skov 3和A2 780居中。结论　RhoC的表达与卵巢癌细胞的体外侵袭和迁移能力相关 ,可能作为一个独立因素在卵巢癌的转移过程中起作用 ,有望成为阻断卵巢癌转移的新靶点。     

乙酰肝素酶在膀胱移行细胞癌中的表达及其与预后的关系

 目的 探讨乙酰肝素酶（HPA）在膀胱移行细胞癌组织中的表达及其对膀胱癌预后判断的意义。方法 应用免疫组化法，分别对80份膀胱癌组织中HPA的表达和微血管密度（MVD）进行检测。20份非肿瘤膀胱组织作为对照。结果 80份膀胱癌组织中HPA阳性率57.5%（n＝46），非癌膀胱组织中HPA表达均为阴性，两组差异有统计学意义（P＜0.01）。HPA表达阳性率随着膀胱癌分期、分级的增高及淋巴结转移而升高（P＜0.05）。膀胱癌组织中HPA阳性组MVD值为45.24±9.95，显著高于阴性组 （34.0±10.34）（P＜0.01）。HPA表达阳性组的膀胱癌患者的2、3、5年生存率低于阴性组（分别P＜0.05，P＜0.05和P＜0.01），COX模型多因素分析显示HPA是膀胱癌的一种独立预后不良因子。结论 HPA的表达与膀胱移行细胞癌的临床病理特征和新血管生成相关，是膀胱癌一种新的独立预后不良因子     

Expression of decorin, a small leucine-rich proteoglycan, as a prognostic factor in soft tissue tumors

BACKGROUND AND OBJECTIVES: Decorin is a major extracellular matrix protein which has recently become the focus of various cancer studies. However, there have so far been no reports describing the clinicopathological implications of decorin in soft tissue tumors. The aim of this study was to examine whether decorin expression is a prognostic factor in soft tissue tumors. METHODS: Decorin expression was examined in 85 samples obtained from 77 patients by real-time quantitative PCR and immunohistochemistry. RESULTS: Lower levels of decorin were expressed in liposarcoma and malignant peripheral nerve sheath tumor than in lipoma (<0.01) and neurofibroma (P < 0.05), respectively. An immunohistochemical analysis for spindle-cell sarcomas demonstrated decorin protein to be produced by myofibroblastic cells in the peripheral stromal extracellular spaces. On a Kaplan-Meier analysis, lower levels of decorin were associated with lower disease-free and overall survival rates (P < 0.05) in 31 spindle-cell sarcomas. A multivariate analysis revealed a significant correlation between a reduced decorin expression and a poor disease-free survival (P = 0.04). In all seven patients with recurrent or metastatic lesions, the decorin expression levels were lower in secondary lesions than in primary lesions. CONCLUSIONS: A reduced decorin expression was found to be a useful biomarker of aggressiveness in soft tissue tumor.     

Loss of p21Waf1 expression is a strong predictor of reduced survival in primary superficial bladder cancers.

p21Waf1 is a downstream effector of p53 and belongs to the Cip1/Kip1 family of cyclin-dependent kinase inhibitors. Thus, it is a potential tumor suppressor gene and likely plays an important role in tumor development. Moreover, reduced expression of p21Waf1 has been reported to have prognostic value in several human malignancies. In this study, we evaluated the prognostic value of p21Waf1 in bladder cancer compared with other clinicopathological features and with p27Kip1 and p53 expression. A total of 96 superficial (pTa-1) human bladder carcinomas were immunohistochemically stained for p21Waf1 protein expression. Positive p21Waf1 staining (> or =5% positive nuclei) was observed in 68 of the 96 (71%) tumors. p21Waf1 expression was neither associated with tumor stage (P = 0.9) nor with tumor grade (P = 0.18) but was significantly associated with both p53 protein expression (> or =20% positive nuclei; P = 0.007) and with p53 gene mutations (P = 0.017). A significant correlation was also observed between positivity for p21Waf1 and high (>50% positive cells) p27Kip1 expression (P = 0.04). With regard to prognosis, patients whose tumors showed absence of p21Waf1 staining displayed a significantly shorter overall survival (P = 0.01 by log-rank test). However, p21Waf1 expression did not correlate with disease-free survival (P = 0.15 by log-rank test). On a multivariate analysis that also included p53 and p27Kip1 expression, negative p21Waf1 staining was an independent predictor of reduced overall survival (P = 0.004; relative risk, 5.32), stronger than age and tumor stage. These data indicate that expression of p21Waf1 protein strongly correlates with survival and might represent a useful prognostic marker in primary superficial bladder carcinomas.