1027

CDKN1B

cyclin-dependent kinase inhibitor 1B (p27, Kip1);CDKN1B;cyclin-dependent kinase inhibitor 1B (p27, Kip1)

cyclin-dependent kinase inhibitor 1B

12p13.1-p12

protein-coding

BACKGROUND: The cyclin-dependent kinase inhibitor p27 plays a central role in cell cycle progression and is deregulated in breast carcinomas. Although its levels are inversely associated with tumor proliferation, overexpression of p27 has been reported in a subset of rapidly proliferating breast carcinoma cell lines. METHODS: p27 levels were determined by immunohistochemistry in a series of 52 sporadic invasive breast carcinomas consisting of 47 ductal, 2 lobular, and 3 mixed; most tumors were Grade 2 or 3 (46 of 52) and tumor Node metastasis (TNM) Stage II-IV (46 of 52). E-cadherin expression and its gene alterations at 16q22.1 were also studied, because in vitro evidence suggests a biologic association between p27 and E-cadherin-mediated growth suppression. RESULTS: The mean p27 labeling index (LI; percentage of p27 positive tumor cells) was 33.3% +/- 25.3% (range, 0.1-85%). High p27 levels (p27 LI, > 50%) were observed in 14 (26.9%) of 52 carcinomas and were significantly associated with metastatic disease in axillary lymph nodes (14 of 33 vs. 0 of 19; P = 0.0007 by Fisher exact test). In addition, p27 LI was higher in the group of lymph node positive vs. lymph node negative tumors (mean p27 LI, 40.9% vs. 20.1%; P = 0.008 by Mann-Whitney test). Reduced or absent E-cadherin expression was found in 27 of 45 (60%) informative cases. Allelic imbalance of the 16q22.1 locus was found in 14 (27.5%) of 51 cases by using the microsatellite markers D16S503, D16S752, and D16S512. p27 LI and E-cadherin alterations were not statistically related. CONCLUSIONS: In summary, high p27 levels detected in a subset of advanced breast carcinomas correlate with lymph node metastasis, suggesting that other mechanisms may bypass the cell cycle inhibitory role of p27 and provide growth advantage in these tumors.

OBJECTIVE: The aim of this study was to clarify whether the evaluation of cell-cycle regulatory protein p27 can serve as a prognostic factor in patients with International Federation of Gynecology and Obstetrics (FIGO) stage IB cervical carcinoma. PATIENTS AND METHODS: A retrospective study was performed on 130 surgically treated patients with FIGO stage IB cervical carcinoma with at least a 5-year follow-up. The expression of p27 was investigated independently by 2 experienced pathologists using immunohistochemistry. The prognostic significance of established prognostic factors and p27 expression were analyzed using univariate and multivariate analyses. RESULTS: In a univariate analysis, lymph node status, tumor diameter, Gynecologic Oncology Group (GOG) score, lymph vascular space invasion, and p27 expression were significant prognostic factors for overall survival (OS). We found a correlation between p27 expression and lymph node status, tumor diameter, invasion, and GOG score. The p27 expression was a statistically significant prognostic factor for OS in a univariate analysis (log-rank test, P = 0.03). In a multivariate analysis, only lymph node status and tumor diameter were statistically significant prognostic factors for OS. CONCLUSIONS: This study demonstrated that a low p27 expression is associated with lymph node metastasis, deep stromal invasion, tumor diameter more than 20 mm, and high GOG score and had a prognostic influence on OS in a univariate analysis in a series of 130 women with FIGO stage IB cervical carcinoma. Lymph node status and the diameter of the tumor were the only statistically significant prognostic factors in multivariate analysis.

BACKGROUND & OBJECTIVE: It has been reported that p27 is associated with prognosis of some tumor. This study was designed to investigate the relationship between expression of p27 and prognosis of colorectal carcinoma. METHODS: The expression of p27 in 82 colorectal carcinoma specimens was detected by immunohistochemical method. The relationship between the expression of p27 and clinicopathological characteristics or survival time was analyzed by chi 2 test or log rank test, respectively, while univariate and multivariate prognostic analyses were performed by using Cox regression model. RESULTS: High p27 expression rate in colorectal carcinoma was 53.66% (44/82), while low expression rate was 46.34% (38/82). Low p27 expression in colorectal carcinoma was significantly associated with late Dukes stage, high incidence of lymph metastasis, and distant metastasis. Long rank test showed that the p27 expression was positively correlated to survival time and Cox regression indicated that the p27 was an prognostic marker of colorectal carcinoma. CONCLUSION: Low p27 expression in colorectal carcinoma was significantly associated with late Dukes stage, high incidence of lymph metastasis, and distant metastasis, poor prognosis, and short survival time. p27 is an prognostic marker of colorectal carcinoma.

BACKGROUND/AIMS: p27 protein resulted in the accumulation of cyclin E/cyclin dependent kinase 2/p27 ternary complexes inhibits gap1 to synthesis phase transition. Here, we have investigated the correlations, if any, between the expressions of p27 and p53, and proliferation cell nuclear antigen. METHODOLOGY: A retrospective study was performed on 75 cases of gastric cancer that had undergone surgical resection. Immunohistochemical staining was performed using the avidin-biotin-peroxidase complex technique method, with anti-p27 antibody, anti-p53 antibody and anti-proliferation cell nuclear antigen antibody. RESULTS: The rate of lymph node metastasis in the p27 negative cases was significantly higher than that in the p27 positive cases.The rate of tumor limited to the gastric wall in the p27 positive cases was significantly higher than-that in the p27 negative cases.The mean proliferation cell nuclear antigen index of the p27 negative cases was significantly higher than that of the p27 positive cases. The survival rate of the p27 positive cases was significantly higher than that of the p27 negative cases. In Stage III cases, the survival rate of the p53 negative p27 positive or p53 negative p27 negative cases was significantly higher than that of p53 positive p27 negative cases. CONCLUSIONS: p27 was correlated with lymph node metastasis, depth of invasion, and proliferative activity of gastric cancer. Immunoreactivity of combination of p53 and p27 was a useful predictive marker of prognosis of gastric cancer.

In intrahepatic cholangiocarcinomas (ICCs), the prognostic significance of p27(Kip1), a cyclin-dependent kinase inhibitor, remains controversial, and there have been no studies of degradation pathway associated proteins, S-phase kinase-interacting protein (Skp2), and Jun activation domain-binding protein-1 (Jab1). In the present study of 74 patients with ICC-mass forming type (ICC-MF) undergoing radical surgery, we determined immunohistochemical expression of p27(Kip1), Skp2, and Jab1 and examined relationships with clinicopathologic findings and patient survival. On the basis of the average of labeling indices, we set cutoff values to define high and low expressors and divided the cases into two groups. A statistically significant correlation was found between low p27(Kip1) expression and lymph node metastasis (P = .009). Patient survival in the low p27(Kip1) expression group (n = 25) was also significantly worse than that in the high p27(Kip1) expression group (n = 49, P = .0007). A significant inverse correlation was found between p27(Kip1) and Skp2 expression (P = .016). High Skp2 expression (n = 36) was significantly associated with poor prognosis (P = .0046). High Jab1 expression was observed in 32 cases, but there was no statistically significant relationship with clinicopathologic findings or patient survival. The multivariate analysis revealed that low p27(Kip1) and high Skp2 expression are independent and significant factors of poor prognosis. The results suggest that low p27(Kip1) and high Skp2 expression are associated with aggressive tumor behavior, and these cell-cycle regulators are useful markers to predict outcome of patients with ICC-MF.

AIM: To investigate p27 expression in hepatocellular carcinoma (HCC), adjacent nontumoral and normal liver tissues, and to verify whether the subcellular localization of p27 was altered in HCC. METHODS: The level of p27 in tumoral, nontumoral, and normal liver tissues were assessed by immunohistochemical (IHC) analysis. Parallel immunostaining was done for proliferating cell nuclear antigen (PCNA) to evaluate cell proliferation. RESULTS: The labeling index (LI) of p27 in tumoral lesions was significantly lower than that in adjacent nontumoral lesions (t=2.444, P=0.017) and normal controls (t=2.268, P=0.029). The LI of p27 significantly decreased in patients with massive type (t=2.227, P=0.037) and infiltration (t=2.197, P=0.036). The prognosis of patients with higher p27 LI was longer than that of patients with lower p27 LI (P=0.0247, log-rank test). The LI of PCNA was significantly higher in HCC than that in adjacent nontumoral lesions (t=2.092, P=0.041) and normal controls (t=3.533, P=0.002). There was no significant correlation between p27 expression and cell proliferation in tumor samples. The level of p27 in the cytoplasmic fraction was higher in tumoral and nontumoral liver tissues, and was associated with clinical stage (t=2.520, P=0.029) and the degree of invasion (t=2.640, P=0.019). Survival analysis showed that p27 was an independent prognosis marker for HCC patients. CONCLUSION: These results suggest that p27 underexpressing in patients with HCC is closely associated with infiltration, metastasis, and prognosis. Alterations in the subcellular localization of p27 protein may occur early during hepatocarcinogenesis.

BACKGROUND/AIM: p27(Kip1) (p27) is a member of the Cip/Kip family of cyclin/cyclin-dependent kinase inhibitors (CKIs), and its CKI-independent function regarding cell motility modulation has been discovered. However, it is controversial whether p27 promotes or inhibits cell migration. This study investigates the migration regulatory role of p27 in metastatic hepatocellular carcinoma (HCC) cells. METHODS: RNA interference, RhoA-GTP pull-down assay, Western blots, immunostaining, transwell and wound-healing assays were used. RESULTS: High levels of p27 and phosphorylated p27 (Ser10) were detected in metastatic HCC cells, MHCC97L and MHCC97H, when compared with nonmetastatic HCC cells, PLC and Hep3B. We hypothesized that p27 is responsible for metastasis-related migration in HCC cells and tested the hypothesis by using the p27 RNA interference approach. Increased RhoA activity was observed when p27 was knocked down in MHCC97L cells, which further led to stress fiber formation and decreased cell migration and wound healing. Moreover, high p27 and low stathmin expression of metastatic HCC cells indicated that migration inhibition by p27-stathmin interaction might not be the major regulatory pathway in metastatic HCC cells. CONCLUSION: p27 promotes cell migration in metastatic HCC cells through the regulation of RhoA activity.

Decreased expression of p27 (a cyclin-dependent kinase inhibitor) is an adverse prognostic marker in a diverse array of human cancers. The purpose of this study was to investigate the expression of p27 and Jab1 (a protein involved in p27 degradation) in melanocytic lesions, and to identify their possible participation in melanoma progression. A tissue microarray was constructed using formalin-fixed, paraffin-embedded archival tissue blocks of 94 melanocytic lesions including 19 benign nevi, 21 dysplastic nevi, 23 melanomas, and 31 metastatic melanomas. The expression of p27 and Jab1 was evaluated by immunohistochemistry. The association between p27, Jab1, and clinicopathological parameters was analyzed using chi2 and Fisher's exact tests. Nonparametric Pearson's rank correlation was applied to evaluate the relationship between p27 and Jab1 expression. p27 was expressed in 15 (88%) nevi, 18 (95%) dysplastic nevi, 11 (50%) melanomas, and only in four (13%) of the metastatic melanomas (P<0.001). Jab1 was expressed in 14 (82%) standard nevi, 18 (95%) dysplastic nevi, 17 (77%) melanomas, and 16 (53%) of the metastatic melanomas (P<0.01). In metastatic melanomas, there was a negative correlation between p27 and Jab1 expression (r=-0.166). The low levels of p27 in primary and metastatic melanoma cases may explain the high proliferation rate of such lesions. Also, the relative high expression of Jab1 in metastatic melanoma, associated with low levels of p27, suggests that Jab1 may be involved in survival and proliferation of metastatic melanoma cells.

p27Kip1 is a cyclin-dependent kinase inhibitor which regulates progression of cells from G1 into S phase in a cell cycle. p27Kip1 has been reported to be an important prognostic factor in various malignancies. As the ability of invasion and metastasis has been thought to be the most important factor for patient's prognosis, we examined whether up-regulation or down-regulation of p27Kip1 can affect the ability of invasion and metastasis of an oral cancer cell (B88t cell) in vitro and in vivo. We constructed an expression vector containing sense- or antisense-oriented human p27Kip1 cDNA with pcDNA3.1. We transfected B88t cells with the empty vector, the sense- or antisense-oriented expression vector to regulate the expression of p27Kip1 gene. Up-regulation of p27Kip1 protein markedly inhibited the migration of cancer cells in a Boyden chamber. Down-regulation of p27Kip1 protein markedly enhanced the migration of cancer cells in a Boyden chamber, and the tumor invasion in nude mice. Moreover, we detected up-regulation of E-cadherin and down-regulation of Tiam-1 (tumor invasive and metastasis-1) in the sense transfectants, up-regulation of Tiam-1 and down-regulation of E-cadherin in the antisense transfectants by Western blotting. These results suggest that p27Kip1 may play an important role in the invasion and metastasis of an oral cancer cell involved in regulation of E-cadherin and Tiam-1.

Interactions between the cyclin-dependent kinase inhibitors (CDKI) and human papillomavirus (HPV) infection in the pathogenesis of vulvar carcinoma are still incomplete. This study aimed to evaluate the prognostic relevance of these proteins in vulvar cancer. One hundred and thirty-nine patient specimens assembled in a tissue microarray were evaluated for p16, p21, p27, and pRb by immunohistochemistry. HPV status was assessed by a linear array HPV genotyping test. In 16 cases with available frozen tumor, quantitative real-time reverse transcriptase-polymerase chain reaction for CDKN2A(p16), CDKN1A, and Rb was performed. Protein expression was considered positive in 40 patients for p16, 35 for p21, 28 for p27, and 19 for pRb. HPV was positive in 43 of the 105 evaluable cases. expression of CDKIs and pRb, with the exception of p16, seem to be linked to the early phases of vulvar carcinogenesis. Although p16 and p21 protein expression was associated with early stages of disease, no prognostic significance was found when analyzing CDKI proteins or detecting HPV status, limiting their clinical usage. No association was observed between expression of CDKI proteins and HPV status, suggesting that in spite of this association found in cervical cancer, this seems not to be valid for vulvar carcinoma.