Role of p27Kip1 and Cyclin-Dependent Kinase 2 in the Proliferation of Non-Small Cell Lung Cancer

The cell cycle is governed by a family of cyclin-dependent kinases (Cdks). Cdk2 forms a functional complex with cyclin E and plays a pivotal role in the regulation of G1/S transition. Cdk2 activity is negatively regulated by interactions with inhibitors. p27^Kip1, one of the most potent inhibitors of Cdk2, was recently identified as a powerful negative prognostic marker in non-small cell lung cancer as well as in colorectal and breast cancer. In the present study, the expression of p27 and Ki-67 antigen in nonneoplastic and cancerous lung tissues was determined by immunohistochemistry. After establishing that the antibody-measured p27 labeling index was a good reflection of the level of p27 expression measured by Western blotting, we show that p27 labeling index is decreased in cancerous lung tissues, compared with nonneoplastic lung tissues, and exhibits a significant inverse relation to the proliferation marker Ki-67 antigen, detected with monoclonal antibody MIB-1. Consistent with these data, all cancerous lung tissues showed enhanced degradation activity of p27 compared with nonneoplastic lung tissues and, in addition, increased levels of the phosphorylated form of Cdk2, as determined with Western blot analysis. The H1 histone kinase activity associated with Cdk2 was also increased in non-small cell lung cancers. Statistical analysis showed that proliferative activity as measured by MIB-1 labeling index was highly correlated with Cdk2 activity (r = 0.767, P < 0.0015). These results suggest that p27 and Cdk2 may play an important role in the proliferation of non-small cell cancer.     

磷酸化P27kip1的表达与非霍奇金淋巴瘤的恶性相关

目的探讨P27kip110位丝氨酸(Ser10)和187位苏氨酸(Thr187)磷酸化形式的蛋白质表达水平与非霍奇金淋巴瘤(NHL)恶性程度的关系。方法采用免疫组织化学方法检测88例NHL及15例良性增生淋巴结中Ser10、Thr187磷酸化P27kip1和P27kip1蛋白的表达,结合临床及病理资料进行统计分析。结果两种磷酸化位点的P27kip1蛋白在良性增生淋巴结(不包括生发中心)中的阳性率明显低于NHL,随着肿瘤侵袭性的增加,两种磷酸化位点的P27kip1蛋白表达水平增高,与增殖指标Ki-67呈正相关。Thr187磷酸化P27kip1蛋白的阳性率与P27kip蛋白表达水平呈正相关,Ser10磷酸化P27kip1蛋白的阳性率与P27kip1蛋白表达水平表现为负相关。结论磷酸化的P27kip1与NHL的恶性程度有关,联合检测磷酸化P27kip1与P27kip1蛋白的表达水平可为NHL的临床诊断和治疗提供参考。     

Expression of cyclin-dependent kinase inhibitor p27kip1 in malignant lymphomas

p27kip1 is a cyclin-dependent kinase inhibitor that regulates progression from G1 into S phase. Aberrations in cell cycle control are often observed in tumors and might even be necessary in tumor development. Recent reports showed that low p27kip1 expression is associated with poor prognosis in several tumors and leukemia. To investigate the expression of p27kip1 in malignant lymphomas and elucidate the role of p27kip1 as a possible prognostic indicator, the authors performed an immunohistochemical staining of p27kip1 correlated with Ki-67 labelling index and clinical parameters. p27kip1 expression was reduced variably in most malignant lymphomas and inversely correlated with Ki-67 labelling index (p=0.0151). Regarding chemotherapeutic response, p271kip1 expression in the complete remission group showed statistically significant difference in expression compared to the progressive disease group (p=0.0021). There were significant differences in survival between cases with low and high p27kip1 expression (p=0.0071). In a multivariate Cox analysis, p27kip1 expression was independent prognostic factors as well as other known prognostic factors including age, grade, stage and chemotherapeutic response. In conclusion, the study suggests that reduced expression of p27kip1 protein may play a role in the pathogenesis and biologically aggressive behavior of malignant lymphomas.     

Expression of p27kip1 in breast cancer and its prognostic significance

p27kip1 is a member of the KIP/CIP family of cyclin-dependent kinase inhibitors and is a negative cell-cycle regulator that is thought to play a role in tumour suppression. Reduced levels of this protein have been observed in a number of human cancers. However, evidence is conflicting as to whether p27kip1 has a role to play in breast cancer, including predicting behaviour and prognosis. The present investigation aimed to provide a definitive study of 830 breast cancer cases with median patient follow-up of 104 months to determine the true prognostic significance, if any. Immunohistochemical analysis of tissue microarrays and three scoring methods were used to assess p27kip1 expression. Univariate analysis showed a significant relationship between reduced p27kip1 expression and increasing tumour grade, nuclear pleomorphism, mitosis, and decreasing tubule formation (all p<0.001). Significant associations between reduced p27, negative oestrogen receptor status, and ductal/no special type tumours were also observed. Survival analysis demonstrated that patients with tumours with high p27kip1 levels had an improved survival compared with those with cancers with low expression. On multivariate analysis, when compared with existing factors, p27kip1 was not, however, an independent prognostic factor. It is concluded that the inverse relationship between p27kip1 levels and histological grade and individual grade components suggests a role for p27kip1 in both cell proliferation and differentiation, but is not clinically useful.     

胃肠道类癌中p27kip1、PCNA表达及p16基因缺失

目的 :探讨 p2 7kip1 、PCNA及 p1 6与胃肠道类癌转移的关系。 方法 :采用免疫组化SABC法检测 2 5例胃肠道类癌组织中p2 7kip1 和PCNA蛋白表达 ,同时用PCR法检测 p1 6基因的缺失情况。 结果 :p2 7kip1 在胃肠道类癌阳性表达率为 64 % (1 6/ 2 5) ,PCNAⅠ～Ⅱ级和Ⅲ～Ⅳ级表达率分别为 56 %、44 %。 2种蛋白阳性表达率与分化程度无相关性 (P >0 0 5) ,与淋巴结转移相关 (P <0 0 5)。p2 7kip1 与PCNA表达负相关。p1 6基因纯合性缺失率为 48% (1 2 / 2 5) ,其缺失率与类癌分化程度和淋巴结转移无关。结论 :p2 7kip1 低表达、PCNA高表达与胃肠道类癌转移有关 ,胃肠道 ;类癌的发生与p1 6基因缺失有关 ,但可能为早期分子事件。     

卵巢上皮性肿瘤中Skp2、p27kip1 、E-cad的表达

目的 检测Skp2、p27kip1和E-cad在卵巢上皮性肿瘤中的表达情况及其相互关系.方法 采用免疫组化SP法,检测99例卵巢上皮性肿瘤组织中Skp2、p27kip1及E-cad的表达.结果 p27kip1在卵巢良性肿瘤、交界性肿瘤的表达率分别为76.5%、70.6%高于卵巢癌29.2%(P<0.05),在早期癌中的表达高于晚期癌(P<0.05).Skp2在卵巢良性肿瘤、交界性肿瘤的表达率分别为0、23.5%,均低于卵巢癌50.8%(P<0.05),在早期癌的表达低于晚期癌(P<0.05).卵巢癌中Skp2表达与组织分化有关,在低分化癌的阳性表达率高于高分化癌(P<0.05),在组织学类型方面,浆液性癌中skp2的阳性表达率高于非浆液性癌(P<0.05).E-cad在良性肿瘤、交界性肿瘤和卵巢癌表达率分别为88.2%、82.4%、55.4%,恶性组低于良性组(P<0.05).E-cad在早期癌的表达率高于晚期癌(P<0.05).Skp2表达与p27kip1表达呈负相关(P<0.05),E-cad表达与p27kip1表达呈正相关(P<0.05),而E-cad表达与Skp2表达则呈负相关(P<0.05).结论 Skp2过度表达与p27kip1表达减少可能与卵巢上皮性肿瘤的发生发展密切相关,而E-cad在晚期卵巢癌中表达降低可能反映了卵巢癌分化程度的降低.     

Prostate Stem Cell Compartments : Expression of the Cell Cycle Inhibitor p27Kip1 in Normal, Hyperplastic, and Neoplastic Cells

The stem cells of rapidly renewing tissues give rise to transiently proliferating cells, which in turn give rise to postmitotic terminally differentiated cells. Although the existence of a transiently proliferating compartment has been proposed for the prostate, little molecular anatomical evidence for its presence has been obtained to date. We used down-regulation of the cyclin-dependent kinase inhibitor p27^Kip1 to identify cells capable of entering the proliferative phase of the cell cycle and, therefore, competent to fulfill the role of the transiently proliferating compartment. We examined the expression of p27^Kip1 in relation to its role in the development of prostatic carcinoma. Formalin-fixed paraffin-embedded specimens from matched samples of normal-appearing prostate tissue, benign prostatic hyperplasia, high-grade prostatic intraepithelial neoplasia, primary adenocarcinomas, and pelvic lymph node metastases were evaluated by comparative immunohistochemistry against p27^Kip1. In normal-appearing prostate epithelium, moderate to strong nuclear staining of p27^Kip1 was present in greater than 85% of the terminally differentiated secretory cells. The normal basal cell compartment, believed to contain prostatic stem cells, showed distinctive p27^Kip1 expression; acini in epithelial benign prostatic hyperplasia tissue contained more p27^Kip1-negative basal cells than acini from non-benign prostatic hyperplasia tissue. A third layer of cells was identified that was sandwiched between the basal cells and the luminal cells, and this layer was consistently p27^Kip1 negative. This intermediate layer was accentuated in the periurethral region, as well as in prostate tissue that had been subjected to prior combined androgen blockade. We hypothesize that, on appropriate additional mitogenic stimulation, cells in this layer, and other p27^Kip1-negative basal cells, are competent for rapid entry into the cell cycle. Consistent with the fact that cancer cells are capable of cell division, all cases of high-grade prostatic intraepithelial neoplasia and invasive carcinoma also showed down-regulation of p27^Kip1 as compared with the surrounding normal-appearing secretory cells. In pelvic lymph node metastases, p27^Kip1 expression was also reduced. In summary, our results suggest that lack of nuclear p27^Kip1 protein may delineate a potential transiently proliferating subcompartment within the basal cell compartment of the human prostate. In addition, these studies support the hypothesis that reduced expression of p27^Kip1 removes a block to the cell cycle in human prostate epithelial cells and that dysregulation of p27^Kip1 protein levels may be a critical early event in the development of prostatic neoplasia.     

Expression of p27/kip1 is down-regulated in human prostate carcinoma progression

p27^Kip1 is a cyclin-dependent kinase inhibitor whose down-regulation has been observed in several tumour models, including breast, colorectal, and gastric carcinomas. The purpose of this study was to assess p27^Kip1 protein expression in normal and benign prostatic epithelia as well as the possible existence of abnormalities in prostate carcinoma progression. p27^Kip1 expression was immunohistochemically analysed in 51 normal tissue samples, 11 nodular hyperplasias (NH), 22 high-grade prostatic intraepithelial neoplasias (PIN), 56 localized prostate adenocarcinomas, and 19 metastases. Immunoblotting was performed in ten cases. Normal prostate epithelium and NH showed diffuse and intense p27^Kip1 nuclear expression in most cases. A significant p27^Kip1 down-regulation was observed in many carcinomas when compared with benign epithelium. Forty-seven cases (84 per cent) were low p27^Kip1 expressors (<50 per cent positive cells) and nine cases (16 per cent) were high p27^Kip1 expressors. p27^Kip1 down-regulation was also consistently seen in PIN. Fourteen out of 19 metastases (74 per cent) were low p27^Kip1 expressors. Six metastatic samples had their corresponding primary tumour analysed and three cases showed decreased expression in the metastasis. It is concluded that p27^Kip1 is constitutively expressed in normal and benign prostatic tissue. This expression is clearly down-regulated in neoplastic progression from the preinvasive lesions through invasive carcinoma and metastases and this therefore occurs in early stages of neoplastic transformation. Copyright © 1999 John Wiley & Sons, Ltd.     

鼻咽癌中p27kip1表达及其与临床病理特征相关研究

Objective To inrestigate the expression of p27kip1 protein and its association with clinicopathologic features in nasopharyngeal carcinoma. Methods Immunohistochemistry was performed to detect p27kip1 expression in 60 paraffin- embedded nasopharyngeal carcinoma samples and 30 paraffinembedded non-cancer nasopharyngeal tissue samples. Results Nuclear and cytoplasmic p27kip1 staining was detected in nasopharyngeal carcinoma samples. Of 60 nasopharyngeal carcinoma samples, 46.7% (28/60)were positive for p27kip1 in cell nuclei, compared with as found in non-cancer nasopharyngeal tissue [90%(27/30), P＜0.01 ], and 68.3% (41/60) were positive in cytoplasma, compared with 20% (6/30) of noncancer nasopharyngeal tissue (P＜0.01). Both nuclear and cytoplasmic expression of p27kip1 were not associated to tumor size and local invasion, while positive nuclear expression of p27kip1 was significantly associated to nodal and remote metastasis and TNM stage. Cytoplasmic expression of p27kip1 was associated to nodal infiltration and TNM stage. Conclusions Compared to that in non-cancer tissue, p27kip1 is upregulated in cytoplasm and down- regulated in nuclei of nasopharyngeal carcinoma tissue, presenting a mislocalization. Less or no nuclear expression of p27kip1 may be associated to malignant progression of nasopharyngeal carcinoma. Abnormal expression and location of p27kip1 may be associated to nasopharyngeal stage and metastasis.     

鼻咽癌中p27kip1表达及其与临床病理特征相关研究

目的 检测p27kip1蛋白在鼻咽癌中的表达,分析其与临床病理特征的关系.方法 收集60例手术活检切取的鼻咽癌组织蜡块,与30例非肿瘤鼻咽组织石蜡标本作比较.应用免疫组织化学技术检测鼻咽癌组织中p27kip1蛋白的表达,回顾性研究鼻咽癌患者的临床病理特征.结果 p27ksp1蛋白在鼻咽癌细胞核和细胞质中均有表达.鼻咽癌组织中细胞核表达阳性率为46.7%(28/60),低于非肿瘤鼻咽组织细胞核表达的90%(27/30),P＜0.01;而在细胞质中阳性率为68.3%(41/60),显著高于非肿瘤鼻咽组织的细胞质表达的20%(6/30),P＜0.01.未发现p27kip1蛋白在细胞核和细胞质表达与鼻咽癌原发灶的范围和局部侵犯程度有关,但p27kip1蛋白胞核表达与淋巴结转移、远处转移和TNM临床分期有关;细胞质表达仅与淋巴结转移和TNM临床分期有关,可见p27kip1蛋白胞核表达与临床病理的关系更为密切.结论 与非肿瘤鼻咽组织相比,p27kip1蛋白为细胞核低表达、细胞质高表达.鼻咽癌中p27kip1蛋白存在不同于非肿瘤鼻咽组织的错误的核质定位,其在细胞核中表达的减少或丢失可能与鼻咽癌的恶性发展有关,提示p27kip1蛋白的异常表达和定位可能涉及鼻咽癌的分期和转移.     

Expression of p27kip1 and p53 in medulloblastoma: relationship with cell proliferation and survival

p27kip1 and p21cip1 are cyclin-dependent kinase (cdk) inhibitors which along with p53 play critical roles in the control of cell cycle progression. Accumulation of p27kip1 in post-mitotic neurons is a major event of neurogenesis. We hypothesized that a dysregulation of the expression of p53 and these cdk inhibitors underlies cellular proliferation in medulloblastomas, and tested this hypothesis by investigating p27kip1, p21cip1, Bcl2 and p53 immunoreactivity in 14 medulloblastoma tumors. We noted an inverse relationship between p27kip1 expression and cellular proliferation (MIB1). Focal islands of neuroblastic or glial differentiation expressed high levels of p27kip1, while the undifferentiated, highly-proliferative population of tumor cells showed no detectable p27kip1 expression, thus suggesting a role for p27kip1 in cell cycle control in medulloblastoma. In addition, there was no detectable p21cip1 expression in any of the medulloblastomas studied. The low level of apoptosis displayed by these tumors was not associated with the expression of Bcl-2. A significant relationship was found between detection of p53 protein and poor survival. Since, p21cip1 and p27kip1 are often co-expressed with other INK4 family of cdk inhibitors during the induction of cellular differentiation and are synergistic in their effect, a deregulation of their coordinate expression may underlie the lack of complete differentiation in medulloblastoma.     

Expression of the Cell Cycle Inhibitor p27KIP1 Is a New Prognostic Marker Associated with Survival in Epithelial Ovarian Tumors

This case-control study was designed to identify factors associated with long-term survival. We examined two groups of patients with epithelial ovarian cancer, one group of long-term survivors (>5 years) and one group of short-term survivors (<2 years), for levels of expression of p53 and p27^KIP1 proteins (as both proteins have been shown to be independent prognostic markers in tumors other than ovary) and the relationship with patient survival. Our findings show that p27^KIP1 expression, in contrast to p53 expression, is positively associated with long-term survival in univariate analysis (P = 0.001), in analyses stratified by residual disease (P = 0.02) or performance status (P = 0.02), the two strongest prognostic factors for ovarian cancer, as well as multivariate analysis (P = 0.002) adjusting simultaneously for age, tumor stage, residual disease, performance status, and grade of differentiation. Therefore, immunostaining for levels of p27^KIP1 expression may have potential as a new prognostic factor in the management of ovarian cancer.     

Skp2和p27kip1与肿瘤间关系的研究进展

目的：探讨Skp2和p27kip1与恶性肿瘤发生、发展的关系。方法：查阅相关中外文献,分析Skp2和p27kip1的生物学特性和功能以及与常见恶性肿瘤的关系。结果：Skp2通过泛素蛋白酶体途径降解磷酸化的p27kip1,促使细胞由G1期进入S期,导致肿瘤的发生。结论：Skp2-p27kip1可能代表一种致癌通路,其与肿瘤的关系正受到越来越多的重视。     

p27(kip1) and Other Cell-Cycle Protein Expression in Normal and Neoplastic Endocrine Tissues

Endocrine tumors are often diagnostic challenges. Recent studies have suggested that proteins that regulate cell cycle may have diagnostic and prognostic utility in endocrine tumors. p27^{kip 1} (p27) is a cyclin-dependent kinase inhibitor that regulates the transition from the G1 to the S phase of the cell cycle. p27 and other cell-cycle proteins are becoming increasingly important in assessing the biologic behavior of endocrine neoplasms, classifying hyperplastic and neoplastic endocrine tissues, and in the progression of endocrine tumors. p27 appears to separate normal from neoplastic endocrine tissues and, in some cases, benign from malignant endocrine tumors. However, there is overlap in p27 expression among individual cases of benign and malignant tumors, and p27 has only limited prognostic utility in endocrine tumors compared to some epithelial tumors such as breast and prostate neoplasms. Thus, more effective molecular and cellular markers that can be used for diagnostic and prognostic purposes in endocrine pathology are needed.     

stathmin和P27kip1在大肠癌中的表达及意义

目的:探讨stathmin蛋白与p27kip1蛋白在大肠癌组织中的表达及意义.方法:应用免疫组织化学SABC法检测25例正常大肠黏膜组织、25例大肠腺瘤组织、47例大肠癌组织中stathmin蛋白及p27kip1蛋白的表达情况.结果:①stathmin蛋白在正常大肠黏膜组织、大肠腺瘤组织及大肠癌组织中的阳性表达率分别为20％、48％、74.47％;正常大肠黏膜组分别与大肠腺瘤组及大肠癌组比较,差异均有统计学意义(P＜0.05);大肠腺瘤组与大肠癌组比较,差异亦有统计学意义(P＜0.05):stathmin蛋白的表达与肿瘤的分化程度、有无淋巴结转移及TNM分期显著相关(P＜0.05).②p27kap1蛋白在正常大肠黏膜组织、大肠腺瘤组织及大肠癌组织中的阳性表达率分别为92％、80％、31.91％.正常大肠黏膜组与大肠癌组比较,差异有统计学意义(P＜0.05);大肠腺瘤组与大肠癌组比较,差异亦有统计学意义(P＜0.05);正常大肠黏膜组与大肠腺瘤组比较,差异无统计学意义(P＞ 0.05);p27kip1蛋白的表达与肿瘤的分化程度及淋巴结转移有关(P＜0.05).③stathmin蛋白的表达与p27kip1蛋白的表达呈负相关(r=--0.695 3,P＜0.01).结论:stathmin蛋白在大肠癌组织中高表达,其表达程度与肿瘤的分化程度、淋巴结转移及TNM分期显著相关,p27kip1蛋白在大肠癌组织中低表达,其表达程度与肿瘤的分化程度及淋巴结转移显著相关,提示stathmin及p27kip1蛋白共同参与了大肠癌的发生、发展;stathmin蛋白可作为一种判断大肠癌恶性程度及侵袭转移的生物学指标.     

p27kip1、p16蛋白和增殖细胞核抗原在鼻咽癌中的表达及其意义

目的 研究p27^kip1、p16蛋白及增殖细胞核抗原(PCNA)在鼻咽癌(NPC)组织中的表达,探讨它们之间的关系及其与．NPC生物学行为及预后的相关性。方法应用免疫组织化学EnVision两步法检测66例鼻咽非角化性癌(NKC)组织和25例鼻咽黏膜慢性炎症(NP)组织中p27^kip1、p16蛋白及PCNA表达水平。结果(1)．NKC组织中p27^kip1、p16阳性表达率分别为65％、68％;与NP组比较,差异有统计学意义(P＜0．05)。(2)＜、p16蛋白在NKC中的表达与NKC颅神经侵犯及治疗后5年生存率有关(P＜0．05),与临床分期、淋巴结转移无关(P＞0．05);PCNA表达与．NKC临床分期及治疗后5年生存率有关(P＜0．05),与淋巴结转移、颅神经侵犯无关(P＞0．05)。(3)p27^kip1、p16及PCNA阳性表达之间有相关性(P＜0．05)。结论检测p27^kip1、p16蛋白及PCNA有助于综合评估NKC的预后。     

Expression of p21<Superscript>cip1</Superscript>, p27<Superscript>kip1</Superscript>, and p16<Superscript>INk4a</Superscript> Cyclin-Dependent Kinase Inhibitors in Papillary Thyroid Carcinoma: Correlation with Clinicopathological Factors

In a variety of human malignancies, aberrant expression of proteins involved in the control of cell-cycle progression has been reported. In this study, p21^cip1, p27^kip1, and p16^INk4a cyclin-dependent kinase inhibitors were analyzed to evaluate their usefulness in clinical management of papillary thyroid carcinoma (PTC). Archived material derived from 46 cases of PTC was analyzed immunohistochemically. Protein expression was ascertained on tissue microarrays, and results were correlated with clinicopathological features of the patients. Positive immunostaining was observed in 14 (30,4%) p21^cip1, 26 (56,5%) p27^kip1, and 14 (30,4%) p16^INk4a cases. No significant correlation between p21^cip1 or p27^kip1 and clinical factors was found. In contrast, p16^INk4a expression showed a significant correlation with initial extension of the disease. Therefore, 45.8% of patients with loco-regional extension were p16^INk4a positive, whereas overexpression was only seen in 15.7% of cases with intrathyroid disease (p < 0.05). Moreover, all patients with simultaneous p16^INk4a positivity and lack of p27^kip1 staining (four patients) presented lymph node metastases. In contrast, only 12 (28.5%) of the remaining patients showed lymph node tumor involvement. In conclusion, p16^INk4a expression suggests extrathyroid neck extension of PTC. This effect is enhanced when p27^kip1 is negative. We think that their analysis by immunohistochemistry could be useful in the management of patients with PTC.     

Aberrant p27kip1 expression in endocrine and other tumors.

The p27kip1 (p27) gene encodes an inhibitor of cyclin-dependent kinase activity. The expression of p27 protein in normal and neoplastic tissues was investigated by immunoblotting and immunohistochemistry. Immunoblotting studies detected a 27-kd protein band that was decreased in neoplastic pituitary tissues compared with normal pituitary. Immunostaining of 177 tissues showed abundant expression of p27 protein in normal tissues with decreased numbers of immunoreactive cells in adenomas and carcinomas in both endocrine and nonendocrine tissues. p27 expression was inversely related to the proliferation marker Ki-67 antigen detected with monoclonal antibody MIB-1. Parathyroid adenomas and hyperplasias had similar Ki-67 labeling indices; however, hyperplasias had threefold more p27-positive cells than parathyroid adenomas, suggesting that p27 immunostaining may be useful in distinguishing between these two conditions. These results indicate that there is widespread aberrant p27 expression in hyperplastic tissues and in benign and malignant neoplasms compared with normal tissues. Immunohistochemical analysis of p27 along with Ki-67 may be used to assess the biological behavior of various neoplasms, to classify hyperplastic and neoplastic tissues, and to study cell cycle regulation during tumor progression.