流式细胞术对食管癌组织中四种细胞周期调控蛋白的定量检测及意义

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

p57 KIP2 、cyclin D1 和cyclin E 在宫颈鳞癌中的表达及意义

 目的 探讨p57^KIP2、cyclin D1及cyclin E蛋白在宫颈癌发生、发展中的作用。方法 用免疫组织化学SP法检测100例宫颈鳞癌、60例宫颈上皮内瘤变和30例正常宫颈鳞状上皮组织中p57 KIP2、cyclin D1和cyclin E蛋白的表达情况。结果 cyclin D1、cyclin E蛋白在宫颈SCC与NE、CIN与NE组织中阳性表达率之间比较、cyclin E蛋白在宫颈SCC与CIN组织中阳性表达率之间比较,差异均有显著性（P〈0．01）;cyclin D1与cyclin E之间的表达呈正相关（P〈0．01）;三者表达均与组织学分级、淋巴结转移、患者年龄无关（P〉0．05）。结论 p57 ^KIP2、cyclin D1及cyclin E蛋白共同参与了宫颈癌的发生发展。cyclin D1和cyclin E蛋白高表达可能是宫颈组织恶变的重要生物学标志,cyclin E异常表达是宫颈癌发生的早期事件。     

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

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

非小细胞肺癌组织中PTEN/p27kip1的表达及其意义

目的检测PTEN、p27kip1、cyclin 3种蛋白在非小细胞肺癌组织的表达及与临床病理特征的关系.方法在60例非小细胞肺癌原发灶(包括37例鳞癌和23例腺癌)中应用免疫组织化学S-P法检测3种蛋白的表达.结果 60例肺癌原发灶中PTEN、p27kip1、cyclin 3种蛋白表达阳性率分别为:48.3%;41.7%;73.3%.PTEN与淋巴结转移显著相关(<0.05)p27kip1、cyclin 与淋巴结转移无关(>0.05)这3种蛋白表达均与肿瘤细胞分化程度显著相关(<0.05)与组织学类型无关(>0.05)60例非小细胞肺癌组织中,PTEN的表达与p27kip1呈显著正相关(P<0.01),而与cyclin 无明显相关(>0.05)p27kip1与cyclin 的表达之间呈显著负相关(P<0.01).结论 PTEN明显地抑制了非小细胞肺癌的浸润和转移,p27kip1表达缺失与肺癌细胞的分化有关,PTEN/p27kip1衰老诱导途径在非小细胞肺癌的恶性进展中起着很重要的作用.     

细胞周期调节蛋白在食管鳞癌组织中的表达

背景与目的:研究表明肿瘤细胞周期分析显示细胞具高增殖率的肿瘤,其临床病情发展快;细胞周期调节蛋白Ki-67、细胞周期蛋白A及p27介入到细胞的增殖,但这些因子与食管癌之间的关系的研究在我国尚未见报道。本研究观察细胞周期调节蛋白Ki-67、细胞周期蛋白A及p27在中国食管癌患者中的表达特征,以探讨这些分子标志物与临床病理因素之间的关系。方法:60例(48例男性、12例女性)食管鳞癌患者行外科手术切除肿瘤,其标本行免疫组织化学染色。Ki-67及细胞周期蛋白A表达程度以染色指数表示,p27以标记指数表示。结果:Ki-67、细胞周期蛋白A及p27免疫组化染色在瘤组织与非瘤组织中均固定于细胞核。Ki-67及细胞周期蛋白A的染色指数在低分化鳞癌(27.2±4.9;15.4±5.3)明显高于高分化鳞癌(20.6±6.3;11.3±6.4,P<0.05);p27免疫组化染色的阳性率在高分化鳞癌(36%)高于其它病理类型(29%及18%),但相互之间的差异无统计学意义(P>0.05)。结论:Ki-67、细胞周期蛋白A及p27的表达程度可反映食管鳞癌细胞的增殖状况。细胞周期调节蛋白Ki-67及细胞周期蛋白A的过度表达提示食管鳞癌细胞分化差。     

p57KIP2、cyclin D1和cyclin E在宫颈鳞癌中的表达及意义

目的探讨p57^KIP2、cyclin D1及cyclin E蛋白在宫颈癌发生、发展中的作用。方法用免疫组织化学SP法检测100例宫颈鳞癌、60例宫颈上皮内瘤变和30例正常宫颈鳞状上皮组织中p57^KIP2、cyclin D1和cyclin E蛋白的表达情况。结果cyclin D1、cyclin E蛋白在宫颈SCC与NE、CIN与NE组织中阳性表达率之间比较、cyclin E蛋白在宫颈SCC与CIN组织中阳性表达率之间比较，差异均有显著性（P〈0．01）；cyclin D1与cyclin E之间的表达呈正相关（P〈0．01）；三者表达均与组织学分级、淋巴结转移、患者年龄无关（P〉0．05）。结论p57^KIP2、cyclin D1及cyclin E蛋白共同参与了宫颈癌的发生发展。cyclin D1和cyclin E蛋白高表达可能是宫颈组织恶变的重要生物学标志，cyclin E异常表达是宫颈癌发生的早期事件。     

Expressions of cyclin D1 and p27kip1 in carcinogenesis of stomach mucosa

Objective  To evaluate the relationship between the expressions of cyclin D1 and p27^kip1 in the canceration course of the stomach. Methods  The immunohistochemical staining technique (SP method) was used to detect the expressions of cyclin D1, p27^kip1 in chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), intestinal metaplasia (IM), dysplasia (DYS), gastric carcinoma (GCA) biopsy specimens. Results  The positive cyclin D1 expression rates increased with the progressing from CAG→IM→DYS→GCA respectively, and those in IM, DYS and GCA were different from those in CSG, P < 0.05, while DYS group was indifferent from GCA group, P > 0. 05. The positive p27^kip1 expression rates decreased with the mucosa progressing from CAG→IM→DYS→GCA. There was a negative correlation between the expression cyclin D1 and p27^kip1 (Y = −0.53, P = 0.000). Conclusion  Expression rates of cyclin D1 in the canceration course of the stomach mucosa trend were increased and those of p27^kip1 were decreased; the abnormal expressions of them were found in the early term of the canceration course of the stomach mucosa, and the inverse expression suggests there may be a negative feedback regulatory loop between cyclin D1 and p27^kip1.     

Comparison of deregulated expression of cyclin D1 and cyclin E with that of cyclin-dependent kinase 4 (CDK4) and CDK2 in human oesophageal squamous cell carcinoma.

The expressions of cyclin D1, cyclin E, cyclin-dependent kinase 4 (CDK4), and CDK2 were immunohistochemically examined in 90 patients with human oesophageal squamous cell carcinoma (SCC) to determine their relationship to the tumour behaviour and patient prognosis. Nuclear immunostaining of cyclin D1 and cyclin E was observed in 28 (31.1%) and 27 tumours (30.0%) respectively. Thirty-nine tumours (43.3%) and 31 tumours (34.4%) exhibited both cytoplasmic and nuclear positivity for CDK4 and CDK2 respectively. Of 28 cyclin D1-positive and 27 cyclin E-positive tumours, CDK4 was overexpressed in 12 (42.8%) tumours and CDK2 in seven (25.9%) tumours respectively. There was no significant relationship in immunopositivity between cyclin D1 and CDK4 or between cyclin E and CDK2. Simultaneous immunoreactivity for both cyclin D1 and CDK4 was significantly associated with venous invasion (P < 0.05). In a univariate analysis, the prognosis of patients with tumours that were both cyclin D1- and CDK4-positive was significantly poorer than that of patients with cyclin D1-negative tumours (P < 0.05). In a multivariate analysis, both cyclin D1 and CDK4 immunoreactivities (P < 0.01) and tumour stage (P < 0.001) were recognized as independent risk factors. In this analysis, the hazard ratio for cyclin D1-positive and CDK4-negative cases compared with cyclin D1-negative cases was significant (hazard ratio = 3.128, 95% confidence interval = 1.418-6.899, P = 0.0047). No significant prognostic relevance was detected in both cyclin E and CDK2 immunoreactivity. Our in vivo findings suggest that in human oesophageal SCC, cyclin D1 and cyclin E and their functional partners, CDK4 and CDK2, often exhibit dysregulated overexpression in many cases, and that tumours with simultaneous expression of cyclin D1 and CDK4 are frequently associated with venous invasion and have a worse prognosis, statistically. Moreover, overexpression of cyclin D1 alone may also contribute to tumour progression independent of CDK4 overexpression.     

Role of cyclin E and p53 expression in progression of early gastric cancer

Background. To elucidate the role that cyclin E overexpression plays in the progression of early gastric cancer, we examined the expression of cyclin E and p53, as abnormal p53 expression is linked with cyclin E overexpression in exerting adverse affects on the cell cycle. Methods. Specimens from 108 early gastric cancers were stained by an immunohistochemical method, using anti-cyclin E and anti-p53 antibodies. Results. The positivity rate of cyclin E expression in early gastric cancer was 33% (36/108). Cyclin E-positive tumors invaded more deeply (P < 0.05), infiltrated lymphatic vessels more frequently (P < 0.01), showed a higher incidence of differentiated cancer (P < 0.01), and more often expressed p53 (P < 0.01) than cyclin E-negative tumors. Differentiated cancers showing coexpression of cyclin E and p53 were more likely to metastasize to the lymph nodes. Conclusions. Overexpression of cyclin E may promote the progression of early gastric cancer. Received for publication on Apr. 27, 1998; accepted on Nov. 17, 1998     

Expression of cell cycle regulatory proteins in breast carcinomas before and after preoperative chemotherapy

Molecular markers predicting response to preoperative chemotherapy would be of major clinical relevance in breast cancer. Therefore, we studied the relationship between the expression of cell cycle regulatory proteins and clinical outcome in breast cancer patients receiving preoperative chemotherapy. Expression of p21^Waf1, p27^Kip1, p53, cyclin D3 and Ki-67 was determined in breast carcinomas by means of immunohistochemistry both prior and after preoperative chemotherapy. Expression data were compared with both clinical parameters and response to preoperative chemotherapy with either cyclophosphamide/methotrexate/5-fluorouracil (CMF, n = 29) or epirubicin/docetaxel (ED, n = 36). In paired samples before and after preoperative chemotherapy, the percentage of p21^Waf1, p27^Kip1, p53 and cyclin D3 positive nuclei of tumor cells in postchemotherapy specimens was significantly higher than the percentage in prechemotherapy samples but no change in Ki-67 expression was observed. High Ki-67 expression (p = 0.02), negative estrogen receptor status (p = 0.01) and negative progesterone receptor status (p = 0.04) were associated with complete pathologic response to chemotherapy, whereas the other markers did not predict response. In conclusion, expression levels of p21^Waf1, p27^Kip1, p53 and cyclin D3 significantly increased after preoperative chemotherapy in breast carcinomas but only high Ki-67 expression, negative estrogen receptor status and negative progesterone receptor status were associated with complete pathologic response to preoperative chemotherapy.     

滑膜肉瘤组织中p27和cyclin E的表达及其临床意义

目的：探讨滑膜肉瘤组织中p27蛋白和cyclin E表达与临床病理指标的关系及判断预后的价值。方法：为46例滑膜肉瘤标本及10例正常滑膜组织的存档蜡块．应用免疫组化法观察p27蛋白和eyclin E的表达情况，并进行对比分析和相关性研究。结果：46例滑膜肉瘤组织中p27蛋白的阳性率为19．6％（9／46），正常滑膜组织中为90％（9／10），两者差异有统计学意义，P=0．01。p27蛋白表达与组织学分级有关，P=0．01；与性别、临床分期和组织学类型无关，P〉0．05。p27蛋白低表达者的5年生存率明显低于高表达者．P=0．01。eyclin E在滑膜肉瘤和正常滑膜组织中的表达差异有统计学意义，P=0．00；cyclin E的过表达在滑膜肉瘤的5年生存率组间差异有统计学意义，P=0．00。结论：p27低表达和cyclin E过表达与滑膜肉瘤的发生有关，是其预后差的有意义指标。联合检测p27和cyclin E表达对判断滑膜肉瘤的预后更有价值。     

COMBINED DETECTION OF CYCLIN D1, P27 AND DNA CONTENT IN ESOPHAGEAL CANCER

With the development of histological and cytological techniques, the proteins involved in the cell cycle regulation have been observed in the incoordinate growth and proliferation of tumor. Therefore, it is believed that the occurrence and development of tumor are closely related with the disordered regulation of cell cycle, which is performed by positive and negative regulators. The positive regulators include cyclins and the corresponding cyclin dependent kinase (CDK) while the negative one…     

胆囊癌组织中p57KIP2、cyclin D1和cyclin E的表达及临床意义

背景与目的：原发性胆囊癌（primary carcinoma of the gallbladder,PCG）是死亡率极高的恶性肿瘤,其恶变的机制目前尚未明确。前期研究发现,p57^KIP2在人类多种恶性肿瘤中异常表达。本研究拟进一步探讨p57^KIP2在PCG组织中的表达及临床意义。方法：运用实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR）、免疫组织化学EliVision法分别检测60例PCG、20例胆囊腺瘤（adenoma of the gallbladder,AG）和20例慢性胆囊炎（chronic cholecystitis,CC）组织中p57^KIP2、cyclin D1、cyclin E mRNA表达及蛋白水平。结果：p57^KIP2 mRNA及蛋白在PCG、AG和CC中的表达逐渐升高,两两比较差异有统计学意义（P<0.05）。Cyclin D1、cyclin E mRNA及蛋白在PCG、AG和CC中的表达逐渐降低,PCG与AG比较、PCG与CC比较,差异有统计学意义（P<0.05）。在PCG组织中,p57^KIP2蛋白的表达与临床分期、组织学分级及淋巴结转移有关（P<0.05）。Cyclin D1蛋白的表达与临床分期有关(P<0.05)。p57^KIP2与cyclin D1的表达呈负相关（P<0.05）,p57^KIP2与cyclin E的表达呈负相关（P<0.05）,cyclin D1与cyclin E的表达呈正相关（P<0.05）。结论：p57^KIP2表达的降低与cyclin D1、cyclin E表达的增加可能是PCG的发生机制之一;检测p57^KIP2、cyclin D1及cyclin E对PCG的预后判断有重要意义。     

Cyclin E、CDK2和p21WAF1在食管上皮癌变过程中的表达及意义

目的探讨食管上皮癌变过程中细胞周期调控因子cyclin E、CDK2和p21WAF1的表达状况及其意义.方法应用免疫组化SP法和原位杂交方法分别检测48例食管癌组织、31例非典型增生组织和17例正常食管粘膜中cyclin E、CDK2和p21WAF1蛋白及mRNA表达.应用半定量RT-PCR和Western blot检测22例新鲜食管癌及相应癌旁组织的mRNA和蛋白表达.结果从食管正常粘膜、非典型增生组织到癌组织,cyclin E和CDK2蛋白和mRNA阳性表达率逐渐上升,差异具有统计学意义(P＜0.01或P＜0.05).食管癌组织中cyclin E、CDK2和p21WAF1蛋白及mRNA高表达,与癌旁组织或切缘正常食管粘膜有显著性差异(P＜0.01).cyclin E、CDK2和p21WAF1基因表达显著正相关(P＜0.01或P＜0.05).结论食管上皮癌变过程中,细胞周期相关基因cyclin E和CDK2表达逐渐增强.cyclin E基因表达异常是食管癌变过程中的早期事件.p21WAF1基因在食管癌中高表达,可能与细胞周期调控的反馈机制有关.     

The role of cyclins and cyclins inhibitors in the multistep process of HPV-associated cervical carcinoma

BACKGROUND: Human papillomavirus (HPV) types 16 and 18 are associated with cervical carcinogenesis. This is possibly achieved through an interaction between HPV oncogenic proteins and some cell cycle regulatory genes. However, the exact pathogenetic mechanisms are not well defined yet. METHODS: We investigated 110 subjects (43 invasive squamous cell carcinoma (ISCC), 38 CIN III, 11 CIN II, 18 CIN I) confirmed to be positive for HPV16 and/or 18 as well as 20 normal cervical tissue (NCT) samples for abnormal expression of cyclin D1, cyclin E, CDK4, cyclin inhibitors (p21 (waf), p27, p16 (INK4A)) and Ki-67 using immunohistochemistry and differential PCR techniques. RESULTS: There was a significant increase in the expression of Ki-67, cyclin E, CDK4, p16 (INK4A) (p=0.003, 0.001, 0.001) and a significant decrease in p27 (Kip1) from NCT to ISCC (p=0.003). There was a significant correlation between altered expression of p27 (KIP1) and p16(INK4A) (p<0.001), cyclin D1 and CDK4 (p=0.001), cyclin E and p27 (Kip1) (p=0.011) in all studied groups. In ISCC, there was significant relationship between standard clinicopathological prognostic factors and high Ki-67 index , increased cyclin D1 and cyclin E, reduced p27 (Kip1) and p21 (waf). CONCLUSION: 1) Aberrations involving p27 (KIP1), cyclin E, CDK4 and p16 (INK4A) are considered early events in HPV 16 and 18-associated cervical carcinogenesis (CINI & II), whereas cyclin D1 aberrations are late events (CINIII & ISCC) 2) Immunohistochemical tests for p16 (INK4A) and cyclin E could help in early diagnosis of cervical carcinoma 3) Only FIGO stage, cyclin D1, p27 (Kip1) and Ki-67 are independent prognostic factors that might help in predicting outcome of cervical cancer patients.     

Interaction of retinoblastoma protein and D cyclins during cell-growth inhibition by hexamethylenebisacetamide in TM2H mouse epithelial cells

To explore the regulation and function of D-type cyclins in breast cancer cells, the mouse mammary hyperplastic epithelial cell line TM2H was treated with 5 mM hexamethylenebisacetamide (HMBA), a polar differentiation factor. The resulting growth-inhibitory effect of HMBA was completely reversible and was analyzed in terms of percent cells in G₁; association of D-type cyclins with cyclin-dependent kinase (cdk) 4 and cdk6; G₁ kinase activity; association of retinoblastoma protein (pRb) and phosphorylated pRb with D-type cyclins; and association of p16^INK4a, p15^INK4b, and p27^Kip1 with cdk4 and cdk6. Synchronized TM2H cells were examined at 0, 3, 5, 9, 12, and 24 h after exposure to 5 mM HMBA. Inhibition of DNA synthesis, as measured by thymidine uptake, was first observed at 5 h (40%) and peaked at 24 h (80%). Flow cytometry at 9 h showed treated cells to be in G₁ arrest. Western blot analysis showed weakly detectable cyclin D1 but readily detectable cyclin D2 and D3 proteins at 0 h; thereafter, cyclin D2 and D3 protein levels remained higher while cyclin D1 levels declined significantly in treated versus untreated cells. By 5 h (early G₁), HMBA had markedly inhibited cdk4 and cdk6 kinase activity (67% and 75%, respectively) in treated versus untreated cells. By 9 and 12 h, pRb levels had increased 3.4-fold in treated versus untreated cells. At 5 h, cyclin D–associated pRb was totally hypophosphorylated in treated cells and hyperphosphorylated in untreated cells. The levels of pRb associated with cyclin D2 and D3 increased 2.89-fold and 4.6-fold, respectively, in treated versus untreated cells. At 5 h, treated cells showed a fivefold increase in cdk4-associated p27^Kip1 and, at 9 h, a fourfold increase in cdk6-associated p27^Kip1 over control levels. In confirmation of these data, HMBA was found to inhibit the growth of Rb-positive Du/145Rb cells but not their Rb-negative parental Du/145 cells. The data suggest that HMBA-induced growth inhibition is due to multifactorial mechanisms involving decreases in total cyclin D1 and inhibition of cdk4 and cdk6 kinase activities through elevation of levels of cdk4- and cdk6-associated p27^Kip1 and concomitant increases in hypophosphorylated pRb and stable cyclin D2/pRb and cyclin D3/pRb complexes that help maintain pRb in a functional state. Mol. Carcinog. 22:128–143, 1998. © 1998 Wiley-Liss, Inc.     

Quantitative analysis of the cyclin expression in human esophageal cancer cell lines

To study the altered mechanisms of cell cycle regulation in esophageal cancer, the expressions of cyclins involved in G1/S transition were analyzed in a series of 26 human esophageal cancer cell lines. To evaluate and compare the levels of cyclin expression, flow cytometric analysis was performed using human lymphocytes as control. Increased expressions of cyclin A, D1, D3 and E were found in 23.1% (6/26), 65.4% (17/26), 15.4% (4/26) and 57.7% (15/26) of the cell lines, respectively. All cell lines studied expressed less cyclin D2 than lymphocytes and the majority of the cell lines expressed cyclin D3 at levels similar to those of lymphocytes. Five cell lines expressed exceptionally high levels of cyclin E. Expressions of cyclin D1 and E were significantly elevated as compared to those of cyclin A, D2 and D3. These results suggest that increased expressions of the positive cell cycle regulators cyclin D1 and E may play an important role in esophageal carcinogenesis.     

Prognostic significance of cyclin D1 in esophageal squamous cell carcinoma patients treated with surgery alone or combined therapy modalities

In the present study, the expression of cyclin D1, as detected by immunohistochemistry, was compared with other prognostic variables and its prognostic impact was evaluated in a group of 172 patients with squamous cell carcinoma (SCC) of the esophagus who underwent potentially curative resection therapy and in a second group of 38 patients with SCC of the esophagus who were treated by combined modality therapy (radiochemotherapy ± surgery). Expression of cyclin D1 in surgically treated carcinomas correlated negatively with tumor differentiation (p = 0.026) but positively with mitotic activity (p = 0.0199) and nodal status (p = 0.040). There were no significant correlations with pT category. Patients with cyclin D1‐positive carcinomas showed significantly worse overall survival than patients with cyclin D1‐negative carcinomas, both in univariate (p = 0.0016) and in multivariate survival analyses (p = 0.0038). Expression of cyclin D1 in carcinomas with multimodal treatment was correlated with poor response to chemotherapy (p = 0.026) but not with overall survival. We thus consider expression of cyclin D1 to be an important parameter, predicting an unfavorable overall survival of surgically treated esophageal cancer patients. Int. J. Cancer (Pred. Oncol.) 84:86–91, 1999. © 1999 Wiley‐Liss, Inc.     

Expression of the cell cycle regulator p27(Kip1) in normal squamous epithelium, cervical intraepithelial neoplasia, and invasive squamous cell carcinoma of the uterine cervix. Immunohistochemistry and functional aspects of p27(Kip1).

BACKGROUND: Abnormality of cell cycle regulators and tumor suppressors, such as cyclin dependent kinase inhibitors (cdkIs), has been reported in malignant tumors. The current study was undertaken to examine the involvement of a cdkI, p27(Kip1) (p27), in the neoplastic process of the uterine cervical epithelium. METHODS: Immunohistochemical staining of p27 was performed in samples of normal cervical tissue (30 samples), cervical intraepithelial neoplasias (CINs; 17 samples), and invasive squamous cell carcinoma (SCC; 25 samples). The results were compared with the expression levels of Ki-67, cdk2, and cyclin E. The functional aspects of the p27 protein, such as its ability to bind to cdk2 and the phosphorylation activity of p27-bound cdk2, also were evaluated with an immunoprecipitation and histone H1 kinase assay. RESULTS: In normal cervical epithelia, the expression of p27 was strong in the intermediate and superficial cells but very weak in the parabasal cells. In CIN samples, the expression of p27 was negligible. The expression of p27 in these tissues showed an inverse topologic correlation to that of Ki-67, cdk2, and cyclin E. However, it is noteworthy that the number of p27 positive cells increased in SCC samples that also showed increased expression of Ki-67, cdk2, and cyclin E. The p27 protein in SCC samples was bound to cdk2 and cyclin E. However, cdk2 that was bound to p27 still possessed histone H1 kinase activity. CONCLUSIONS: The expression of p27 may be involved in the growth regulation of the normal squamous epithelium in the uterine cervix. However, aberrant function of p27 expression may occur in invasive SCC of the cervix.