Cyclin E overexpression in transitional cell carcinoma of the bladder

Expression of cyclin D1 and cyclin E in urothelial bladder carcinoma detected in tissue chips using a quantum dot immunofluorescence technique

The present study aimed to investigate the expression of cyclin D1 and cyclin E in tissue chips of bladder cancer using quantum dots (QDs), as well as examine its clinicopathological significance. The QD-based immunofluorescence tissue chemical technique was adopted to detect cyclin D1 and cyclin E expression in 75 tissue chips of human urothelial bladder carcinoma (including 70 cases of urothelial bladder carcinoma and 5 cases of cystitis), and its correlation with clinicopathological features was analyzed. The positive rates of cyclin D1 and cyclin E expression in urothelial bladder carcinoma were 68.6% (48/70) and 70.0% (49/70), respectively; however, no expression was observed in cystitis. Based on the results of statistical analysis, the difference in the positive rates of cyclin D1 and cyclin E expression between urothelial bladder carcinoma and cystitis was significant (P<0.05). QD staining and statistical analysis revealed that the expression of cyclin D1 and cyclin E in urothelial bladder carcinoma was significantly higher compared with that in cystitis (P<0.05). However, no statistically significant difference (P>0.05) in cyclin D1 expression was observed in relation to pathological stage, clinical stage or invasion of urothelial bladder carcinoma; however, there was a significant difference (P<0.05) in cyclin E expression with respect to these factors. These results demonstrated that overexpression of cyclin D1 may be an early event in the occurrence of urothelial bladder carcinoma. Cyclin D1 may play a role in the initial stage where cell proliferation is a necessary step, without invasion or metastasis. In addition, overexpression of cyclin E was correlated with the stage and depth of invasion of urothelial bladder carcinoma. In conclusion, the abnormal expression of cyclin D1 and cyclin E may be involved in the occurrence and development of urothelial bladder carcinoma.

Molecular biology of bladder cancer: prognostic and clinical implications

The role of various molecular determinants involved in the genesis, progression, and outcome of bladder cancer has been the focus of investigations for the past 2 decades. Increasingly, the analysis of the interplay between these molecular factors is taking center stage. We review herein the studies examining the effects of deregulation of the various molecules implicated in the cell cycle, apoptosis, and angiogenesis pathways and analyze the central role of p53 in regulating these pathways. Technological advancements enable detection and quantification of gene transcripts and protein products, helping us move toward achieving the goal of establishing diagnostic, prognostic, and therapeutic marker panels. Recent studies have therefore focused on multiple-marker analyses to generate informative panels that can have greater clinical value for bladder cancer management. The use of molecular marker panels can provide a more objective alternative to clinical parameters for diagnosis and treatment decisions. Clinical trials aimed at treating urothelial carcinoma based on a patient's molecular profile can be predicted to empower clinicians to personalize patient management through increased therapeutic efficacy.

Molecular staging of bladder cancer

Attempts are being made in many laboratories to find new biomarkers for and new methods of molecular staging of bladder cancer. At the forefront of this are the authors from Los Angeles who have contributed the first of four mini-reviews in this section. Other mini-reviews examine the role of hand-assisted laparoscopy in urology, a contribution to the sometimes heated argument about whether laparoscopy should be 'pure' or hand-assisted: in addition, two mini-reviews describe the role of photodynamic diagnosis in managing superficial bladder cancer, and the contribution of non-surgical factors to the success of hypospadias repair.

Induction of centrosome amplification and chromosome instability in human bladder cancer cells by p53 mutation and cyclin E overexpression

Centrosome amplification frequently occurs in human cancers and is a major cause of chromosome instability (CIN). In mouse cells, centrosome amplification can be readily induced by loss or mutational inactivation of p53. In human cells, however, silencing of endogenous p53 alone does not induce centrosome amplification or CIN, although high degrees of correlation between p53 mutation and CIN/centrosome amplification in human cancer can be detected, suggesting the presence of additional regulatory mechanism(s) in human cells that ensures the numeral integrity of centrosomes and genomic integrity. Cyclin E, a regulatory subunit for CDK2 that plays a key role in centrosome duplication, frequently is overexpressed in human cancers. We found that cyclin E overexpression, together with loss of p53, efficiently induces centrosome amplification and CIN in human bladder cancer cells but not by either cyclin E overexpression or loss of p53 alone. We extended these findings to bladder cancer specimens and found that centrosome amplification is strongly correlated with concomitant occurrence of cyclin E overexpression and p53 inactivation but not with either cyclin E overexpression or p53 inactivation alone. Because cyclin E expression is strictly controlled in human cells compared with mouse cells, our findings suggest that this stringent regulation of cyclin E expression plays an additional role underlying numeral homeostasis of centrosomes in human cells and that deregulation of cyclin E expression, together with inactivation of p53, results in centrosome amplification.

Loss of cyclin E requirement in cell growth of an oral squamous cell carcinoma cell line implies deregulation of its downstream pathway

Cyclin E and Cdk2 have been shown to play an important role in G1/S transition of the cell cycle. Two E-type cyclins (E1 and E2) have been identified to date and share functionally similarities. Upregulation of these cyclins has been observed frequently in human cancers. We examined the expression profile of cyclin E1 and E2 in cell lines derived from human oral squamous cell carcinoma (SCC), and found that the expression of cyclin E1 protein was hardly detected in HSC-2 cells. Although cyclin E2 was abundantly expressed, histone H1 kinase activities of both E-type cyclins were virtually undetectable in this cell line. Inhibition of cyclin E1, but not that of E2, by using vectors expressing antisense-oriented their cDNAs induced drastic growth suppression on HOC313 cells that express both E-type cyclins. Inhibition of neither cyclin E1 nor E2 suppressed the growth of HSC-2 cells, and compensatory elevation of cyclin E1 was not evident in cyclin E2-inhibited HSC-2 cells. In contrast, HSC-2 cells expressed cyclin D1 and hyperphosphorylated forms of Rb family proteins, and were arrested in G1 by overexpression of p16(INK4), a specific inhibitor against D-type cyclin activity. These results indicate that HSC-2 cells lost proper growth control specifically mediated by cyclin E and suggest that deregulation of its downstream pathway may contribute to tumorigenesis of oral SCC.

Gene discovery in bladder cancer progression using cDNA microarrays

To identify gene expression changes along progression of bladder cancer, we compared the expression profiles of early-stage and advanced bladder tumors using cDNA microarrays containing 17,842 known genes and expressed sequence tags. The application of bootstrapping techniques to hierarchical clustering segregated early-stage and invasive transitional carcinomas into two main clusters. Multidimensional analysis confirmed these clusters and more importantly, it separated carcinoma in situ from papillary superficial lesions and subgroups within early-stage and invasive tumors displaying different overall survival. Additionally, it recognized early-stage tumors showing gene profiles similar to invasive disease. Different techniques including standard t-test, single-gene logistic regression, and support vector machine algorithms were applied to identify relevant genes involved in bladder cancer progression. Cytokeratin 20, neuropilin-2, p21, and p33ING1 were selected among the top ranked molecular targets differentially expressed and validated by immunohistochemistry using tissue microarrays (n = 173). Their expression patterns were significantly associated with pathological stage, tumor grade, and altered retinoblastoma (RB) expression. Moreover, p33ING1 expression levels were significantly associated with overall survival. Analysis of the annotation of the most significant genes revealed the relevance of critical genes and pathways during bladder cancer progression, including the overexpression of oncogenic genes such as DEK in superficial tumors or immune response genes such as Cd86 antigen in invasive disease. Gene profiling successfully classified bladder tumors based on their progression and clinical outcome. The present study has identified molecular biomarkers of potential clinical significance and critical molecular targets associated with bladder cancer progression.

Immunohistochemical expression of cyclin E in endometrial adenocarcinoma (endometrioid type) and its clinicopathological significance

PURPOSE

Cyclin E is known as a G1-S phase regulatory protein and its abnormal expression has been implicated in cellular proliferation. This study aimed to investigate the correlation of cyclin E expression with tumorigenesis of the endometrium, proliferative activity, and clinicopathological features of endometrial adenocarcinoma.

METHODS

Immunohistochemical staining for cyclin E in addition to cyclin-dependent kinase 2 (cdk2), Ki67, p27, and p53 was performed by the labeled streptavidin-biotin method on formalin-fixed, paraffin-embedded tissues of normal endometria (20 cases), endometrial hyperplasias (20 cases), and endometrial adenocarcinomas (endometrioid type) (127 cases). Positive staining was expressed as a labeling index (LI) based on percentages of positive nuclei in tumor cells.

RESULTS

Immunohistochemistry showed that the nuclei of the cells were positive for cyclin E. Both proliferative and secretory endometria, and endometrial hyperplasia regardless of type were negligible for cyclin E expression. The expression in normal endometrium and hyperplasia was significantly less than that in endometrial adenocarcinomas (P<0.0001). LIs of cyclin E in well-differentiated, moderately differentiated, and poorly differentiated endometrial adenocarcinomas were 31.5+/-33.3%, 37.8+/-31.9%, and 51.1+/-30.8%, respectively. Cyclin E expression increased significantly more in histological grades. The LI of cyclin E in carcinoma was positively correlated with that of cdk2, Ki67, and p53 but not with p27. The cyclin E expression was correlated with myometrial invasion and lymph-vascular space involvement, but not with FIGO stage, lymph node metastasis, coexisting endometrial hyperplasia, estrogen receptor, progesterone receptor, and menopause.

CONCLUSION

Cyclin E as a complex with cdk2 is associated with carcinogenesis and disease progression in endometrial adenocarcinoma, and might be a prognostic indicator of endometrial adenocarcinoma.

High cyclin E and low p27/Kip1 expressions are potentially poor prognostic factors in lung adenocarcinoma patients

Cyclin E is an important regulator of entry into the S phase of the cell cycle. p27/Kip1 (p27) binds to cyclin E/Cdk2 complex and negatively regulates cell proliferation. We immunohistochemically examined the expression of cyclin E and p27 in 98 cases of resected lung adenocarcinoma to evaluate the prognostic significance of cyclin E and p27. Cyclin E was expressed in 16 cases (16%), and p27 was expressed in 41 cases (42%). Using Kaplan-Meier survival analysis, patients with cyclin E positive (P=0.0017) and p27 negative (P=0.011), both individually and in combination (P<0.0001), had a worse prognosis. We also analyzed the relationship of these findings to clinicopathological parameters, which revealed that cyclin E-positive, p27-negative cases had a higher Ki67 expression (P=0.012) and a higher rate of lymph node metastasis (P=0.0078) than other groups. Our results suggested that cyclin E over expression, in association with p27 reduction in particular, may potentially be a poor prognostic factor in lung adenocarcinoma patients. However, to verify the prognostic significance of these factors, a multivariate analysis of a larger number of patients should be undertaken.