Protein expression patterns of cell cycle regulators in operable breast cancer

Background-Aim

To evaluate the prognostic role of elaborate molecular clusters encompassing cyclin D1, cyclin E1, p21, p27 and p53 in the context of various breast cancer subtypes.

Methods

Cyclin E1, cyclin D1, p53, p21 and p27 were evaluated with immunohistochemistry in 1077 formalin-fixed paraffin-embedded tissues from breast cancer patients who had been treated within clinical trials. Jaccard distances were computed for the markers and the resulted matrix was used for conducting unsupervised hierarchical clustering, in order to identify distinct groups correlating with prognosis.

Results

Luminal B and triple-negative (TNBC) tumors presented with the highest and lowest levels of cyclin D1 expression, respectively. By contrast, TNBC frequently expressed Cyclin E1, whereas ER-positive tumors did not. Absence of Cyclin D1 predicted for worse OS, while absence of Cyclin E1 for poorer DFS. The expression patterns of all examined proteins yielded 3 distinct clusters; (1) Cyclin D1 and/or E1 positive with moderate p21 expression; (2) Cyclin D1 and/or E1, and p27 positive, p53 protein negative; and, (3) Cyclin D1 or E1 positive, p53 positive, p21 and p27 negative or moderately positive. The 5-year DFS rates for clusters 1, 2 and 3 were 70.0%, 79.1%, 67.4% and OS 88.4%, 90.4%, 78.9%, respectively.

Conclusions

It seems that the expression of cell cycle regulators in the absence of p53 protein is associated with favorable prognosis in operable breast cancer.

Prognostic value of cyclin E expression in patients with ovarian cancer: a Meta-analysis

PURPOSE

Cell cycle is mainly mediated by cyclins, cyclin- dependent kinases (CDK), and CDK inhibitors. Cyclin E is the main regulator for transition from G1 to S phase, and is involved in cancer pathogenesis, progression and metastasis. Nevertheless, there is still a controversy of the prognostic value of cyclin E overexpression in ovarian cancer patients. This meta-analysis is the first study aimed at analyzing the effect of cyclin E overexpression on the prognosis of ovarian cancer.

METHODS

By systematically searching the PUBMED, EMBASE and MEDLINE databases for relevant articles with publication dates up to January 2016 and selection following inclusion and exclusion criteria, 8 studies with 1470 patients were enrolled in our meta-analysis. The overall survival (OS) of patients with cyclin E overexpression was calculated using hazard ratio (HR) with 95% confidence intervals (CIs). The studies were categorized according to the author and year, demographic data in each study, ovarian cancer related information, and cyclin E cut-off value.

RESULTS

Cyclin E overexpression in ovarian cancer was a poor prognostic factor with statistical significance for OS (HR=1.48, 95%CI: 1.12,1.85). Using confunnel, we found no publication bias in our analysis.

CONCLUSION

Cyclin E might be considered as a prognostic factor for ovarian cancer, as supported by our meta-analysis. However, more high-quality studies should be conducted to find better clinical use of cyclin E in ovarian cancer.

Panobinostat sensitizes cyclin E high, homologous recombination-proficient ovarian cancer to olaparib

OBJECTIVE

Homologous recombination (HR) proficient ovarian cancers, including CCNE1 (cyclin E)-amplified tumors, are resistant to poly (ADP-ribose) polymerase inhibitors (PARPi). Histone deacetylase inhibitors (HDACi) are effective in overcoming tumor resistance to DNA damaging drugs. Our goal was to determine whether panobinostat, a newly FDA-approved HDACi, can sensitize cyclin E, HR-proficient ovarian cancer cells to the PARPi olaparib.

METHODS

Expression levels of CCNE1 (cyclin E), BRCA1, RAD51 and E2F1 in ovarian tumors and cell lines were extracted from The Cancer Genome Atlas (TCGA) and Broad-Novartis Cancer Cell Line Encyclopedia (CCLE). In HR-proficient ovarian cancer cell line models (OVCAR-3, OVCAR-4, SKOV-3, and UWB1.289+BRCA1 wild-type), cell growth and viability were assessed by sulforhodamine B and xenograft assays. DNA damage and repair (pH2AX and RAD51 co-localization and DRGFP reporter activity) and apoptosis (cleaved PARP and cleaved caspase-3) were assessed by immunofluorescence and Western blot assays.

RESULTS

TCGA and CCLE data revealed positive correlations (Spearman) between cyclin E E2F1, and E2F1 gene targets related to DNA repair (BRCA1 and RAD51). Panobinostat downregulated cyclin E and HR repair pathway genes, and reduced HR efficiency in cyclin E-amplified OVCAR-3 cells. Further, panobinostat synergized with olaparib in reducing cell growth and viability in HR-proficient cells. Similar co-operative effects were observed in xenografts, and on pharmacodynamic markers of HR repair, DNA damage and apoptosis.

CONCLUSIONS

These results provide preclinical rationale for using HDACi to reduce HR in cyclin E-overexpressing and other types of HR-proficient ovarian cancer as a means of enhancing PARPi activity.

Roles of Cx43 and AKAP95 in ovarian cancer tissues in G1/S phase

OBJECTIVE

The purpose of this study was to investigate the expression of A-kinase anchor protein 95 (AKAP95), cell cycle protein E1 (cyclinE1) and D1 (cyclinD1), and gap junction protein connexin 43 (Cx43) in ovarian cancer tissues, the relationship between four proteins and clinicopathologic parameters, and the correlation between these proteins.

METHODS

The expression of proteins in 54 cases of ovarian cancer tissues was detected by immunohistochemical method.

RESULTS

The positive expression rates of AKAP95, cyclinD1 and cyclinE1 in ovarian cancer tissues were 72.22%, 66.67% and 79.63%, respectively, which were higher than that of ovarian pericarcinoma tissues expressing as 33.33%, 25% and 8.30% (P<0.05). The positive expression rate of Cx43 in ovarian cancer tissues was 40.74%, which was lower than that of ovarian pericarcinoma tissues expressing as 75%; respectively, and the difference was statistically significant between groups (P<0.05). The expression of cyclinD1 in ovarian cancer tissues was related to the histologic type (P<0.05) while it showed no correlation with the degree of differentiation (P>0.05). Additionally, the expression of AKAP95, Cx43 and cyclinE1 in ovarian cancer tissues showed no correlation with the degree of differentiation or the histologic type (P>0.05). Protein expressions of AKAP95, Cx43 and cyclinE1 were correlated with each other (P<0.05), and the expressions of cyclinD1, cyclinE1 and Cx43 were also correlated with each other (P<0.05). However, AKAP95 and cyclinD1 showed no correlation (P>0.05).

CONCLUSION

AKAP95, cyclinD1 and cyclinE1 play an important role in promoting the process of ovarian cancer formation. The tumor inhibitory effects of Cx43 protein on the pathogenesis of ovarian cancer were weakened. The expression of cyclinD1 in ovarian cancer tissues is related to the histologic type while it shows no correlation with the degree of differentiation. Additionally, the expression of AKAP95, Cx43 and cyclinE1 in ovarian cancer tissues shows no correlation with the degree of differentiation or the histologic type. AKAP95 expression is correlated with Cx43 and cyclinE1 expression; Cx43 expression is correlated with AKAP95, cyclinD1 and cyclinE1 expression; cyclinE1 expression is correlated with AKAP95, Cx43, cyclinD1 expression; cyclinD1 expression is correlated with Cx43 and cyclinE1 expression, while AKAP95 and cyclinD1 show no correlation.

Synergistic effects of AKAP95, Cyclin D1, Cyclin E1, and Cx43 in the development of rectal cancer

OBJECTIVE

To explore the expression of A-kinase anchor protein 95 (AKAP95), Cyclin D1, Cyclin E1, and Connexin43 (Cx43) in rectal cancer tissues and assess the associations between each of the proteins and pathological parameters, as well as their inter-relationships.

METHODS

AKAP95, Cyclin D1, Cyclin E1, and Cx43 protein expression rates were evaluated by immunohistochemistry in 50 rectal cancer specimens and 16 pericarcinoma tissues.

RESULTS

The positive rates of AKAP95, Cyclin E1, and Cyclin D1 proteins were 54.00 vs. 18.75%, 62.00 vs. 6.25%, and 72.00 vs. 31.25% in rectal cancer specimens and pericarcinoma tissues, respectively, representing statistically significant differences (P < 0.05). The positive rate of Cx43 protein expression in rectal cancer tissues was 44.00% and 62.50% in pericarcinoma tissues, and the difference between them was not significant (P > 0.05). No significant associations were found between protein expression of AKAP95, Cyclin E1, Cyclin D1, and Cx43, and the degree of differentiation, histological type, and lymph node metastasis of rectal cancer (P > 0.05). However, significant correlations were obtained between the expression rates of AKAP95 and Cyclin E1, Cyclin E1 and Cyclin D1, Cyclin E1 and Cx43 protein, and Cyclin D1 and Cx43, respectively (P < 0.05).

CONCLUSION

AKAP95, Cyclin E1, and Cyclin D1 protein expression rates were significantly higher in rectal cancer tissues compared with pericarcinoma samples, suggesting an association between these proteins and the development and progression of rectal cancer. In addition, the significant correlations between the proteins (AKAP95 and Cyclin E1, Cyclin E1 and Cyclin D1, Cyclin E1 and Cx43 protein, and Cyclin D1 and Cx43) indicate the possible synergistic effects of these factors in the development and progression of rectal cancer.

Cyclin E is overexpressed by clear cell carcinomas of the endometrium and is a prognostic indicator of survival

OBJECTIVE

Upregulation of cyclin E and cyclin D1-6 accelerates the transition from G1 to S phase. The objective of this study was to determine if cyclin D1 and E are prognostic indicators in endometrial cancer.

MATERIALS AND METHODS

Surgically-treated patients with endometrial carcinoma had their tumors stained for nuclear expression of cyclin D1 and E. Quantification of staining and measurement of growth phase fraction were performed using image analysis. FIGO stage, grade, and histology were also analyzed.

RESULTS

Cyclin D1 and E expression was unrelated to DNA index (p = 0.93). While cyclin D1 expression did not correlate with S+G2M phase fraction (p = 0.69), increased cyclin E expression was directly correlated with increased S+G2M phase fraction (p = 0.002). Cyclin E expression was highest in clear cell carcinomas (p = 0.042) while cyclin D1 expression was highest in adenosquamous carcinomas (p = 0.028). Patients dying from cancer had significantly higher expression of cyclin D1 (p = 0.042) and E (p = 0.02) as compared to patients surviving their disease. Multivariate logistic regression revealed FIGO stage, grade, and lack of cyclin E overexpression to be independent prognostic indicators of survival.

CONCLUSION

Cyclin E expression is related to increased growth fraction, clear cell histology, and decreased survival in patients with endometrial cancer.

The role of estrogen in the survival of ovarian tumors--a study of the human ovarian adenocarcinoma cell lines OC-117-VGH and OVCAR3

BACKGROUND

The role of estrogen in the growth and survival of ovarian cancer cells is controversial. In this study, we investigated the changes in cell-cycle regulatory proteins in ovarian cancer cell lines after estrogen treatment to explore the role of estrogen in ovarian cancers.

METHODS

Two ovarian adenocarcinoma cell lines were used for the study: the first, OC-117-VGH, was deficient in estrogen receptors (ER)α and ERβ, and the second, OVCAR3, was positive for ERα and ERβ. Serial concentrations of estrogen were used to evaluate the effects of estrogen on the survival of ovarian cancer cells. The cell-cycle regulatory proteins, including cyclin D1, cyclin E, p16/INK4a, and p27/KIP1, were used to check the possible mechanism of an estrogen effect on survival of the cancer cell line.

RESULTS

Estrogen 0.01-1.0 μM inhibited the growth of both cell lines. There were no differences in cyclin D1 and E expression between the two cell lines after estrogen treatment, but the expression of p16/INK4a and p27/KIP1 was significantly higher in the OC-1170-VGH cell line than in the OVCAR3 cell line.

CONCLUSION

Although the ER-positive and ER-negative ovarian cancer cell lines were inhibited by estrogen, the influence of cell-cycle regulatory proteins was different between the two, suggesting that the inhibitory effect of estrogen on ovarian cancer cell lines might be mediated through different pathways.

FSH inhibits ovarian cancer cell apoptosis by up-regulating survivin and down-regulating PDCD6 and DR5

Ovarian epithelial cancer is the leading cause of death among gynecological malignancies. FSH may increase the risk of ovarian malignancy and play an important role in ovarian carcinogenesis. Our previous studies showed that FSH increases the expression of VEGF through survivin. In this study, the function and mechanism of FSH in ovarian cancer were further explored. We found that FSH promoted proliferation and prevented apoptosis of ovarian cancer cells by activating survivin through the SAPK/JNK and PI3K/AKT pathways. FSH also down-regulated the expression of programmed cell death gene 6 (PDCD6) and death receptor 5 (DR5), two molecules required for induction of apoptosis. RNA interference was applied to knock down survivin and PDCD6 expression, and we found that the blockage of survivin reversed the effects of FSH on apoptosis and proliferation, whereas knock down of PDCD6 enhanced these effects. The expression of DR5, cyclin D1, and cyclin E correlated with survivin expression, but PDCD6 did not. Using immunohistochemical staining, we further showed that ovarian serous cystadenocarcinoma samples had higher expression of survivin than did benign ovarian cystadenoma and borderline cystadenoma samples (P<0.01). Furthermore, survivin expression in the ovarian serous cystadenocarcinoma specimens was correlated with disease stage (P<0.05). Our results suggest that FSH promotes ovarian cancer development by regulating the expression of survivin, PDCD6, and DR5. Greater understanding of the molecular mechanisms of FSH in ovarian epithelial carcinogenesis and development will ultimately help in the development of a novel targeted therapy for ovarian cancer.

Inverse relationship between E-cadherin and p27Kip1 expression in renal cell carcinoma

The cell-cell adhesion system plays a pivotal role in the maintenance of tissue structure and cell-cell communication. E-cadherin is a major adhesion protein of the epithelial cells, and E-cadherin expression may be involved in the regulation of cell proliferation or differentiation. To address the relationship between cell-cell adhesion and cell proliferation, we focused on the alteration of p27Kip1 (p27), a cyclin-dependent kinase inhibitor, by E-cadherin-mediated adhesion. In an immunohistochemical study of 76 cases of renal cell carcinoma (RCC), the p27-labeling index (LI) was 67% in E-cadherin-reduced RCC, but only 28% in E-cadherin-preserved RCC. E-cadherin-expressing cells rarely expressed p27 in various cancers including those of the breast, colon, liver and prostate. In a subconfluent monolayer culture, the E-cadherin levels were increased steadily in the E-cadherin positive RCC cell line ACHN, whereas the p27 levels were decreased. Subsequent exposure of ACHN cells to the E-cadherin-specific function-blocking antibody reduced the growth associated with the increase in p27 and the decrease in phosphorylated epidermal growth factor receptor (EGFR). In the E-cadherin negative RCC cell line Caki-1, these effects were not observed. These results suggest that E-cadherin-mediated adhesion may be involved in the contact stimulation for cell proliferation in part through the downregulation of p27 and the activation of EGFR in human cancers.

Expression Patterns of Cyclins D1, E and Cyclin-Dependent Kinase Inhibitors p21(Waf1/Cip1) and p27(Kip1) in Urothelial Carcinoma: Correlation with Other Cell-Cycle-Related Proteins (Rb, p53, Ki-67 and PCNA) and Clinicopathological Features

INTRODUCTION

The expression pattern of cyclins D1 and E, as well as cyclin-dependent kinase inhibitors p21(Wa1/Cip1) and p27(Kip1) and their relationship to tumour behaviour and patients' prognosis was examined in 142 urothelial cell carcinomas. The expression of these proteins was also analyzed along with other cell-cycle-related proteins such as: p53, pRb and the proliferation-associated indices Ki-67 and proliferating cell nuclear antigen (PCNA).

PATIENTS AND METHODS

These molecule markers were localized immunochemically using the monoclonal antibodies anti-cyclin D1 (DCS-6), anti-cyclin E (13A3), anti-p21 (4D10), and anti-p27 (1B4) in 142 patients with urothelial cell carcinoma.

RESULTS

Focal positivity (<10% of tumour cells) or the absence of cyclin D1 immunostaining was observed in 105/142 (73.9%) of the tumours. Cyclin D1 expression was correlated with tumour grade and stage as well as with the existence of in situ component. In addition, cyclin D1 expression was positively correlated with p21(Waf1/Cip1) and p27(Kip1) and inversely with the Ki-67 score. Focal positivity (<20% of tumour cells) or the absence of cyclin E immunoreactivity was observed in 105/142 (73.9%) in all cases. Cyclin E expression was correlated with tumour stage. A positive relationship between cyclin E expression and the two associated proliferating indices Ki-67 and PCNA, as well as with p53 and p27(Kip1) proteins expression was noted. Absence or focal positivity (<5% of tumour cells) of p21(Waf1/Cip1) was detected in 88/142 (62%) of the carcinomas. p21(Waf1/Cip1) expression was correlated with tumour grade and stage. A positive relationship of its expression cyclin D1, cyclin E, p27 and pRb expression was observed. Absence or focal immunostaining (<20% of tumour cells) of p27 protein was detected in 55/141 (39%) in all cases. p27(Kip1) expression was correlated with tumour grade as well as with cyclins D1 and E. The prognostic significance of cyclins D1, E and cyclin-dependent kinase inhibitors p21(Waf1/Cip1), p27(Kip1) in determining the risk of recurrence and progression with both univariate (log rank test) and multivariate (Cox regression) methods of analysis showed no statistically significance differences.

CONCLUSION

These findings suggest that the level of the cell cycle regulators studied does not seem to have a clinical value in terms of predicting the risk of early recurrence and progression. In addition the interrelationship probably means their contribution to the regulation of cell growth through different pathways in bladder carcinogenesis.

Biphasic response of endothelial progenitor cell proliferation induced by high glucose and its relationship with reactive oxygen species

In this study, the effect of high glucose (HG) on endothelial progenitor cell (EPC) proliferation and its relationship with cyclins and reactive oxygen species (ROS) were investigated. Mouse EPCs were isolated from bone marrow using a magnetic activated cell-sorting system and cultured in the presence or absence of HG (30 mmol/l). We found that in the early stage of incubation (3 days), HG promoted cell proliferation, and increased the expressions of cdk2 and cyclin E, while in the late stage of culture (7 days) it inhibited cell proliferation and decreased the expressions of cdk2, cyclin E, and proliferating cell nuclear antigen (PCNA). Moreover, on the third day after incubation, HG significantly inhibited the apoptosis of EPCs, while in the late stage it markedly activated caspase-3 and promoted apoptosis. ROS generation in cells and maleic dialdehyde level in medium were significantly increased in HG group on the seventh day, whereas the expressions of superoxide dismutase and glutathione levels decreased. Tempol, a membrane-permeable radical scavenger, significantly inhibited ROS production in EPCs and partially reversed the HG-mediated inhibition of EPCs proliferation on the seventh day. We hypothesize that in the HG environment, the biphasic response of EPC proliferation may be related to the generation of ROS, which causes modulation of cyclins and cell cycle effect.

Altered pattern of Cul-1 protein expression and neddylation in human lung tumours: relationships with CAND1 and cyclin E protein levels

The Cul-1 protein is the scaffold element of SCF complexes that are involved in the proteasomal degradation of numerous proteins regulating cell cycle progression. Owing to this central role in cell growth control, aberrant expression of the components of SCF is thought to play a role during tumourigenesis. Nothing is known about Cul-1 expression in human tumours. In this study, we have analysed its status in a series of 128 human lung carcinomas, comprising 50 non-small cell lung cancers (NSCLCs; 29 squamous cell carcinomas and 21 adenocarcinomas) and 78 neuroendocrine (NE) lung tumours (24 typical and atypical carcinoids, 19 large cell NE carcinomas and 35 small cell lung carcinomas), using immunohistochemistry. We report for the first time an altered pattern of Cul-1 expression in human tumours; indeed, we show that Cul-1 expression is up-regulated in 40% (51/128) of all lung tumours as compared to normal lung tissues, including 34% (17/50), 75% (18/24) and 30% (16/54) of NSCLCs, carcinoids and high grade neuroendocrine lung carcinomas, respectively. Furthermore, we demonstrate that high levels of Cul-1 protein are associated with a low KI67 proliferative index (p = 0.005) and with a decrease in the cyclin E oncoprotein (p = 0.0003), one of the major targets of SCF complexes. These data suggest that up-regulation of Cul-1 could protect cells from hyperproliferative signals through cyclin E down-regulation. Cul-1 is modified by neddylation, a post-translational modification that grafts ubiquitin-like Nedd8/Rub1 residues and controls Cul-1 activity. We also provide evidence that neddylated forms of Cul-1 are specifically expressed in high-grade NE lung tumours and are associated with down-regulation of the Cul-1 inhibitor CAND1 (p = 0.03) and a high level of cyclin E (p = 0.0002). These data support the notion that alterations in the Cul-1 neddylation/deneddylation pathway could contribute to the development of these highly aggressive lung tumours.

Low-molecular weight forms of cyclin E differentiate ovarian carcinoma from cells of mesothelial origin and are associated with poor survival in ovarian carcinoma

BACKGROUND

The authors recently reported on the role of cyclin E in differentiating ovarian/primary peritoneal carcinoma from malignant peritoneal mesothelioma using gene expression arrays. In the current study, they analyzed the expression of low-molecular weight (LMW) forms of cyclin E in ovarian carcinoma, malignant mesothelioma, and benign reactive effusions.

METHODS

Cyclin E protein expression was analyzed in 98 effusions (72 ovarian carcinomas, 14 malignant mesotheliomas, and 12 reactive specimens) using immunoblotting. Sixty-two ovarian carcinoma effusions were studied further for cyclin E expression using immunohistochemistry. The correlations between cyclin E expression in ovarian carcinoma and clinical parameters, including chemotherapy response, were analyzed.

RESULTS

LMW forms of cyclin E were identified in 54 of 72 ovarian carcinoma effusions (75%) compared with 1 of 14 malignant mesothelioma effusions (7%) and 1 of 12 reactive effusions (8%) (P < .001). Their presence in ovarian carcinoma was associated with a higher percentage of cyclin E-positive cells (P = .001) and increased staining intensity (P < .001) using immunohistochemistry. The presence of LMW forms of cyclin E was correlated with shorter overall survival (P = .021) and progression-free survival (P = .020). The presence of a higher percentage of cyclin E-positive cells using immunohistochemistry was correlated with shorter progression-free survival (P = .026). No association with chemotherapy response was observed.

CONCLUSIONS

LMW forms of cyclin E differentiated ovarian carcinoma from benign and malignant mesothelial cells and were associated with increased protein expression using immunohistochemistry. The expression of LMW cyclin E forms was not associated with chemotherapy response, although it may be a marker of aggressive disease in patients with metastatic ovarian carcinoma.

Cyclin E-associated kinase activity predicts response to platinum-based chemotherapy

PURPOSE

The role of cyclin E as a predictive marker of response to chemotherapy remains unknown. We have previously shown that deregulation of cyclin E in an ovarian tumor cell line model enhances cyclin E-associated kinase activity and sensitizes tumor cells to cisplatinum. We hypothesized that cyclin E deregulation would predict for responsiveness to platinum-based regimens in ovarian cancer patients.

EXPERIMENTAL DESIGN

Patients who met the following criteria were retrospectively identified from the institutional tumor bank records: (a) high-grade ovarian epithelial malignancy, (b) stage III/stage IV disease, (c) optimally debulked, (d) completed platinum-based therapy. Tumor samples were analyzed for cyclin E, p21, and p27 by Western blot analysis and assessed for cyclin E-associated kinase activity.

RESULTS

Seventy-five patients, who met the study criteria, were identified. Cyclin E protein levels did not correlate with cyclin E-cdk2 kinase activity (Spearman's rho, 0.07; P = 0.58). Cyclin E-associated kinase activity was the only significant predictive marker for response to platinum-based therapy, with higher response rates seen in patients with higher levels of activity (P = 0.045). Cyclin E protein levels did not predict for platinum sensitivity (P = 0.20). In contrast, cyclin E protein levels, but not cyclin E-associated kinase activity, was a significant predictor for freedom from recurrence (P = 0.01 and P = 0.25, respectively).

CONCLUSIONS

Cyclin E overexpression and cyclin E-associated kinase activity have distinct roles in predicting for response to chemotherapy and outcome in ovarian cancer patients. These results suggest a compartmentalization of cyclin E functions in the oncogenic process.

Novel p53/p130 Axis in Bladder Tumors

OBJECTIVES

To identify the relationships between key components of the proliferative and apoptotic pathways in bladder tumors.

METHODS

A tissue array of 88 bladder tumors was assembled. Immunohistochemical analyses were used to investigate the relationship between nine different parameters: stage, proliferation (Ki67), apoptosis (in situ DNA nick end labeling), the anti-apoptotic protein Bcl-2, tumor suppressors p53 and retinoblastoma protein (Rb), the Rb-related protein p130, cyclin E, and the cyclin-dependent kinase inhibitor p27. The protein expression in each tumor was reported as the percentage of positively staining cells.

RESULTS

The analysis focused on Stage 1 to 3 tumors. Analysis found that p53 expression increased progressively with stage, and Rb and p27 decreased with increasing stage. Overall, the cyclin E levels correlated with the proliferative index. Cyclin E levels were low in Stage 1 tumors and elevated in Stage 2 tumors, but were decreased in Stage 3 tumors. Multivariate analysis uncovered a correlation between cyclin E and proliferation (Ki67) and a weak correlation between p53 and Bcl-2 and between p27 and Rb. A strong correlation was found between the expression of p53 and p130, which was apparent in Stages 1 and 3, but not in Stage 2. Furthermore, high levels of p130 protein were detected primarily in the cytoplasm.

CONCLUSIONS

These results suggest a novel p53/p130 axis in bladder tumors.

p16 is consistently expressed in endometrial tubal metaplasia

Background: Cell cycle proteins and HIF-1α with downstream factors are often abberrantly expressed in (pre)neoplastic tissue. Methods: Paraffin-embedded specimens of inactive endometrium with TM (n=15), ovarian inclusion cysts (n=6), cervix with TM (tubal metaplasia) (n=3), Fallopian tubes (n=7), cycling endometrium (n=9) and a ciliated cell tumor of the ovary were stained for p16 and LhS28. 39 Endometrioid endometrial carcinomas and 5 serous endometrial carcinomas were stained for p16. Additionally, inactive endometrium (n=15) was immunohistochemically stained for p21, p27, p53, cyclin A, cyclin D1, cyclin E, HIF-1α, CAIX, Glut-1 and MIB-1. Results: A mosaic pattern of expression of p16 was seen throughout in all cases of endometrial TM (15/15), in 2/6 of the ovarian inclusion cysts with TM, in all (3/3) cervical TM and focal in 5/7 of Fallopian tube cases. Mosaic expression was also seen in a ciliated cell tumor of the ovary and in 18/39 of endometrioid endometrial carcinomas, and diffuse p16 expression was seen in 5/5 serous carcinomas. In comparison with normal endometrium, TM areas in the endometrium showed significantly increased expression of HIF-1α, cyclin E, p21 and cyclin A, and decreased expression of p27. Membranous expression of CAIX and Glut-1 was only seen in TM areas, pointing to functional HIF-1α. Conclusion: As p16 is consistently expressed in TM, less and only patchy expressed in the normal Fallopian tube, is paralleled by aberrant expression of cell cycle proteins, HIF-1α, CAIX and Glut-1 and resembles the pattern of p16 expression frequently seen in endometrial carcinomas, we propose endometrial TM to be a potential premalignant endometrial lesion.

Controversial relationship between the expression of the RB pathway components and RB protein phosphorylation in human breast cancer

Recent data challenge the relevance of the RB pathway to cancer based on RB inactivation, at least in breast tumors. To obtain information on the actual role of the components of the RB pathway in tumor progression we decided to investigate whether their quantitative changes were associated with variations in the level of RB phosphorylation in human breast cancer. A series of 68 human primary breast carcinomas was studied. Five cases were excluded from the study due to their lack of RB expression. In the remaining 63 cases the expression of cyclin D1, cdk4, cyclin E, and INK4a mRNA was assessed by real-time RT-PCR. The level of RB phosphorylated protein (ppRB) and p27 expression was immunohistochemically analyzed by measuring the percentage of stained cells (labeling index, LI). Cell proliferation rate was measured by Ki67 LI evaluation. The ppRB LI ranged from 5.2 to 73.8 and, as expected, was strongly related to the Ki67 LI (r=0.80; p<0.001). The expression of cyclin D1 mRNA, expressed in arbitrary units (a. u.), ranged from 1.15 to 123.0 and was inversely related to the ppRB LI (p=0.021) and Ki67 LI (p<0.001). Neither the cdk4 (range from 0.07 to 1.13 a. u.) nor the cyclin E (range from 0.13 to 9.27 a. u.) mRNA expression was significantly associated with the ppRB LI (p=0.962 and p=0.103, respectively). Cyclin E was related to Ki67 LI (p=0.022). Both INK4a mRNA (range from 0.01 to 0.60 a. u.) and p27 (LI from 0.0 to 73.1) values were inversely related to the ppRB LI (p=0.022 and p=0.014, respectively). Cyclin D1, cdk4, and cyclin E mRNA expressions were not significantly related to one another. In human primary breast cancers, the expression levels of the factors known to facilitate the cell cycle progression by RB protein phosphorylation were not positively related to ppRB-LI. Pathological increases of cyclin D, cdk4, and cyclin E are very likely associated with other biological functions other than their well-established action on cell cycle progression.

A candidate precursor to serous carcinoma that originates in the distal fallopian tube

The tubal fimbria is a common site of origin for early (tubal intraepithelial carcinoma or TIC) serous carcinomas in women with familial BRCA1 or 2 mutations (BRCA+). Somatic p53 tumour suppressor gene mutations in these tumours suggest a pathogenesis involving DNA damage, p53 mutation, and progressive loss of cell cycle control. We recently identified foci of strong p53 immunostaining-termed 'p53 signatures'-in benign tubal mucosa from BRCA+ women. To examine the relationship between p53 signatures and TIC, we compared location (fimbria vs ampulla), cell type (ciliated vs secretory), evidence of DNA damage, and p53 mutation status between the two entities. p53 signatures were equally common in non-neoplastic tubes from BRCA+ women and controls, but more frequently present (53%) and multifocal (67%) in fallopian tubes also containing TIC. Like prior studies of TIC, p53 signatures predominated in the fimbriae (80-100%) and targeted secretory cells (HMFG2 + /p73-), with evidence of DNA damage by co-localization of gamma-H2AX. Laser-capture microdissected and polymerase chain reaction-amplified DNA revealed reproducible p53 mutations in eight of 14 fully-analysed p53 signatures and all of the 12 TICs; TICs and their associated ovarian carcinomas shared identical mutations. In one case, a contiguous p53 signature and TIC shared the same mutation. Morphological intermediates between the two, with p53 mutations and moderate proliferative activity, were also seen. This is the first report of an early and distinct alteration in non-neoplastic upper genital tract mucosa that fulfils many requirements for a precursor to pelvic serous cancer. The p53 signature and its malignant counterpart (TIC) underline the significance of the fimbria, both as a candidate site for serous carcinogenesis and as a target for future research on the early detection and prevention of this disease.

Genomic analysis of the 8p11-12 amplicon in familial breast cancer

Amplification of 8p11-12 has been recurrently reported in sporadic breast cancer. These studies define a complex molecular structure with a set of minimal amplified regions, and different putative oncogenes that show a strong correlation between amplification and over-expression such as ZNF703/FLJ14299, SPFH2/C8orf2, BRF2 and RAB11FIP. However, none of these studies were carried out on familial breast malignancies. We have studied the incidence, molecular features and clinical value of this amplification in familial breast tumors associated with BRCA1, BRCA2 and non-BRCA1/2 gene mutations. We detected 9 out of 80 familial tumors with this amplicon by chromosomal comparative genomic hybridization. Next, we used a high-resolution comparative genomic hybridization array covering the 8p11-12 region to characterize this chromosomal region. This approach allowed us to define 2 cores of common amplification that largely overlap with those reported in sporadic tumors. Our findings confirm the molecular complexity of this chromosomal region and indicate that this genomic event is a common alteration in breast cancer, present not only in sporadic but also in familial tumors. Finally, we found correlation between the 8p11-12 amplification and proliferation (Ki-67) and cyclin E expression, which further proves in familial tumors the poor prognosis association previously reported in sporadic breast cancer.

Developmental expression of cell cycle regulators in the baboon fetal adrenal gland

Although the human and the nonhuman primate fetal adrenal glands undergo a highly unique pattern of cortical zone-specific intrauterine growth and development, studies of the regulatory components of the cell cycle responsible for this growth have not been conducted. Therefore, the present study determined expression of the cell cycle regulators, cyclin D1 and cyclin E, and their cyclin-dependent kinases, Cdk2, Cdk4, and Cdk6, and Ki67 a marker of cell proliferation within the baboon fetal adrenal cortex during advancing stages of gestation. Fetal adrenal glands were obtained on days 60 (early), 100 (mid), and 160-170 (late) of gestation (term = 184 days). Mean (+/- s.e.) cyclin D1 mRNA levels, determined by RT-PCR and expressed relative to 18S rRNA, were similar at early (0.85 +/- 0.09) and mid (1.04 +/- 0.08) gestation, then decreased (P < 0.001, ANOVA) approximately 50% by late gestation (0.57 +/- 0.04). Cyclin E mRNA levels were also similar at early (2.03 +/- 0.07) and mid (1.63 +/- 0.31) gestation, and decreased by 70% (P < 0.001) in late gestation (0.53 +/- 0.09). Coinciding with the decrease in cyclin D1 and cyclin E, the percentage of Ki67 positive cells in the definitive zone decreased twofold (P < 0.01) between mid (28.2 +/- 3.6) and late (13.8 +/- 1.7) gestation. The cyclin D1 and cyclin E proteins, determined by immunocytochemistry, were expressed at high levels in the definitive zone of baboon fetal adrenal gland, where they decreased between mid- and late gestation. In contrast, immunocytochemical expression of the functionally important steroidogenic enzyme Delta(5)-3beta-hydroxysteroid dehydrogenase (3beta-HSD) became abundant in the definitive and transitional zones with advancing pregnancy. However, fetal adrenal Cdk2, Cdk4, and Cdk6 mRNA levels and protein immunoexpression were similar in the baboon fetal adrenal at early-, mid-, and late gestation. In summary, expression of cyclin D1, cyclin E, and Ki67 decreased, while 3beta-HSD expression increased, in the fetal adrenal cortex, particularly in the definitive zone, between mid- and late-baboon gestation. We propose that a developmental decline in cellular proliferation permits functional differentiation of fetal adrenal cortical cells, leading to increased production of steroid hormones important for placental estrogen synthesis and maturation of organ systems within the developing fetus.

Cell-cycle inhibition by TNP-470 in an in vivo model of hepatocarcinoma is mediated by a p53 and p21WAF1/CIP1 mechanism

The objective of this study was to determine in a rat model of hepatocellular carcinoma (HCC) the effects of the antiangiogenic agent TNP-470 on cell proliferation and effectors of the apoptotic pathway, including p53, p21WAF1/CIP1, cyclin D, and cyclin E. Tumor was induced in male Wistar rats by diethylnitrosamine and promoted by two-thirds hepatectomy plus acetaminofluorene administration. Experiments were carried out at 28 weeks after initiating the treatment. TNP-470 was administered at 30 mg/kg, 3 times per week from 20 to 28 weeks. Serum levels of vascular endothelial growth factor (VEGF) and hepatocyte growth factor beta (HGFbeta) liver expression were increased by hepatocarcinogenesis (+38% and +183%, respectively), and treatment with TNP-470 was able to prevent the increase in these angiogenic factors induced by HCC. HCC coursed with reduced expression of p21WAF1/CIP1 and p53 (-63% and -60%, respectively). Hepatic expression of cyclin D and cyclin E were significantly increased in rats with HCC (+108% and +115%, respectively). In animals with experimental carcinogenesis, a significant increase in the expression of Cdk4 and CdK2 was also observed (+119% and +187%, respectively). These effects were prevented by TNP-470 administration. In conclusion, cell-cycle inhibition by TNP-470 is mediated at least in part by an activation of p21WAF1/CIP1 because of a p53-dependent mechanism, with reduction of the cyclin D-Cdk4 and cyclin E-Cdk 2 expression. These cytostatic effects should be considered when assessing the efficacy of TNP-470 for anti-angiogenic therapy. These findings may prove useful for the development of therapies for the treatment of human HCC.

Bcl-2 is a prognostic marker in breast cancer independently of the Nottingham Prognostic Index

PURPOSE

Prognostication of breast cancer using clinicopathologic variables, although useful, remains imperfect. Many reports suggest that gene expression profiling can refine the current approach. Alternatively, it has been shown that panels of proteins assessed by immunohistochemistry might also be useful in this regard. We evaluate the prognostic potential of a panel of markers by immunohistochemistry in a large case series to establish if either a single marker or a panel could improve the prognostic power of the Nottingham Prognostic Index (NPI). We validated the results in an independent series.

EXPERIMENTAL DESIGN AND RESULTS

The expression of 13 biomarkers was evaluated in 930 breast cancers on a tissue microarray. Eight markers [estrogen receptor (ER), progesterone receptor (PR), Bcl-2, cyclin E, p53, MIB-1, cytokeratin 5/6, and HER2] showed a significant association with survival at 10 years on univariate analysis. On multivariate analysis that included these eight markers and the NPI, only the NPI [hazard ratio (HR), 1.35; 95% confidence interval (95% CI), 1.16-1.56; P = 0.0005], ER (HR, 0.59; 95% CI, 0.39-0.88; P = 0.011), and Bcl-2 (HR, 0.68; 95% CI, 0.46-0.99; P = 0.055) were significant. In a subsequent multivariate analysis that included the NPI, ER, and Bcl-2, only Bcl-2 (HR, 0.62; 95% CI, 0.44-0.87; P = 0.006) remained independent of NPI (HR, 1.50; 95% CI, 1.16-1.56; P = 0.004). In addition, Bcl-2, used as a single marker, was more powerful than the use of a panel of markers. Based on these results, an independent series was used to validate the prognostic significance of Bcl-2. ER and PR were also evaluated in this validation series. Bcl-2 (HR, 0.83; 95% CI, 0.71-0.96; P = 0.018) retained prognostic significance independent of the NPI (HR, 2.04; 95% CI, 1.67-2.51; P < 0.001) with an effect that was maximal in the first 5 years.

CONCLUSION

Bcl-2 is an independent predictor of breast cancer outcome and seems to be useful as a prognostic adjunct to the NPI, particularly in the first 5 years after diagnosis.

Cyclin E Expression and Outcome in Pancreatic Ductal Adenocarcinoma

The association of high cyclin E expression with poor outcome in some cancers, in particular breast cancer, suggests that it may play an important role in tumor biology. Because the influence of cyclin E expression on outcome is yet to be examined in pancreatic cancer, we assessed the relationship between the expression of cyclin E, p27(Kip1), and survival in a large cohort of pancreatic cancer patients with long-term follow-up. Expression of cyclin E and p27(Kip1) was assessed by immunohistochemistry using tissue microarrays of tumor samples from 118 patients with pancreatic ductal adenocarcinoma (75 resections and 43 biopsies). High cyclin E expression (>10% positive nuclei) was identified in 39 of 118 (33%) patients. This was associated with poor prognosis on univariate analysis in the whole cohort (P = 0.005), as well as in the subgroup of 75 patients who underwent operative resection (P = 0.04). On multivariate analysis, high cyclin E expression was an independent predictor of poor survival in both the entire cohort (P = 0.005) and the resected subgroup (P = 0.03), and was superior to all tested clinicopathologic factors (tumor size, lymph node metastases, differentiation, margin involvement, and perineural invasion) as a marker of survival. Low p27(Kip1) expression (<5% positive nuclei) was present in 41 of 111 (37%) patients, but was not associated with survival, and coexpression of p27(Kip1) did not influence the association of high cyclin E expression with poor survival. High cyclin E expression is a strong independent predictor of poor outcome in patients with pancreatic cancer. Thus, if these data are confirmed in independent cohorts, measurement of cyclin E may add significant prognostic information to the currently used clinicopathologic variables and hence have potential clinical utility in the management of this disease.

The prognostic value and overexpression of cyclin A is correlated with gene amplification of both cyclin A and cyclin E in breast cancer patient

Deregulation of cell cycle control is a hallmark of cancer. The primary cyclins (A, B1, D1, D3 and E) are crucial for cell cycle progression. Secondary cyclins (C and H) have putative indirect effects on cell cycle propulsion and are not previously evaluated in breast cancer. We have examined protein expression and gene amplification of cyclins in breast carcinomas and correlated the findings with clinical follow-up data. We have previously demonstrated that over-expression of cyclin A is associated with poor prognosis in breast cancer patients. In this study we wanted to evaluate the mechanisms behinde overexpression of cyclin A, as well as the impact of other cyclins, both at the gene level and at the protein level, on prognosis of breast cancer patients. The impact of TP53 gene mutations on gene amplification of cyclins was also evaluated. Methods: Real-Time Quantitative PCR was used to detect gene amplification of cyclins in tumour tissue from 86 patients operated for invasive breast carcinomas, while immunohistochemistry was applied to detect protein expression of the same cyclins. Result: Of the 80-breast tumour samples available for cyclin A gene amplification analyses, 26.7% (23/80) was defined to have cyclin A gene amplification. 37.2% (32/79) had cyclin B1 gene amplification, 82.6% (71/82) of the samples harboured amplification of cyclin C gene, 74.4% (64/82) had cyclin D1 gene amplification, 41.9% (36/86) had cyclin D3 gene amplification, 29.1% (25/81) of the patients had cyclin E gene amplification and 9.3% (8/86) of the samples showed amplification of the cyclin H gene. When correlation between gene amplification and protein expression was evaluated, we observed a statistical significant correlation between gene amplification and protein expression of cyclin A (p = 0.009) and cyclin D3 (p < 0.001). However, the correlation between gene amplification and protein expression of cyclin A, as well as the prognostic value of cyclin A overexpression, was affected by gene amplification of cyclin E. Gene amplification of none of the other cyclins was associated with patient prognosis. There was a statistical significant correlation between TP53 gene mutations and gene amplification of cyclins A, D3 and B1. No correlation was observed between gene amplification of secondary cyclins (H and C) and TP53 gene mutations. Conclusions: The overexpression of cyclin A is correlated to gene amplification of both cyclin A and cyclin E. Over-expression of cyclin A is associated with poor prognosis in breast cancer patients. When analysed in a multivariate analyses model, gene amplification as well as protein expression of none of the other cyclins than cyclin A are associated with patient prognosis in breast carcinomas. TP53 gene mutation seems to correlate with gene amplification of primary, but not secondary cyclins.

Cyclin E and p16 Immunoreactivity in Epithelioid Trophoblastic Tumor???An Aid in Differential Diagnosis

Epithelioid trophoblastic tumor (ETT) is a relatively uncommon trophoblastic tumor that can be confused with several trophoblastic and nontrophoblastic lesions, notably the placental site nodule and invasive squamous carcinoma of the cervix. In this report, we analyzed the immunoreactivity of two cell cycle-regulated proteins, cyclin E and p16, in ETTs, placental site nodules and cervical squamous carcinomas to determine whether they are useful in their differential diagnosis. Other trophoblastic lesions were also evaluated. Using an H-score based on both percentage of positively stained cells and immunointensity, we found that ETTs demonstrated a much higher cyclin E staining score than placental site nodules (P<0.0001) permitting distinction of ETTs and placental site nodules with a sensitivity of 94.7% at a specificity of 91.7% using a cutoff H-score value of >40. Only two placental site nodules had scores above the cutoff and both showed morphologic features that placed them in an intermediate position between a typical placental site nodule and an ETT, so-called "atypical PSN." p16 immunoreactivity, was not detected in any of the ETTs and placental site nodules, whereas it was strongly and diffusely positive in the vast majority of cervical squamous carcinomas examined (83/87 cases) (P<0.001). Therefore, cyclin E expression is useful in distinguishing an ETT from a placental site nodule and p16 expression is useful in distinguishing an ETT from a cervical squamous carcinoma. The majority of other types of trophoblastic lesions showed diffuse and intense nuclear immunoreactivity for cyclin E whereas none were positive for p16.

Tissue array analysis of expression microarray candidates identifies markers associated with tumor grade and outcome in serous epithelial ovarian cancer

Molecular profiling is a powerful approach to identify potential clinical markers for diagnosis and prognosis as well as providing a better understanding of the biology of epithelial ovarian cancer. On the basis of the analysis of HuFL expression data, we have previously identified genes that distinguish low malignant potential and invasive serous epithelial ovarian tumors. In this study, we used immunohistochemistry to monitor a subset of differently expressed candidates (Ahr, Paep, Madh3, Ran, Met, Mek1, Ccne1, Ccd20, Cks1 and Cas). A tissue array composed of 244 serous tumors of different grades (0-3) and stages (I-IV) was used in this analysis. All markers assayed presented differential protein expression between serous tumors of low and high grade. Significant differences in Ccne1 and Ran expression were observed in a comparison of low malignant potential and grade 1 tumor samples (p<0.01). In addition, irrespective of the grade, Ccne1, Ran, Cdc20 and Cks1 showed significant differences of expression in association with the clinical stage of disease. While high level of Ccne1 have previously been associated with poor outcomes, here we found that high level of either Ran or Cdc20 appear to be more tightly associated with a poor prognosis (p<0.001, 0.03, respectively). The application of these biomarkers in both the initial diagnosis and prognostic attributes of patients with epithelial ovarian tumors should prove to be useful in patient management.

Cyclin E expression is correlated with tumor progression and predicts a poor prognosis in patients with ovarian carcinoma

BACKGROUND

Cyclins, cyclin dependent kinases (cdks), and their inhibitors act in combination to regulate progression through the cell cycle and often are dysregulated in carcinoma. The authors hypothesized that cyclin E plays an important role in ovarian carcinogenesis and that its overexpression may be an indicator of a poor prognosis.

METHODS

Immunohistochemical analysis of cyclin E expression was performed by image analysis in normal ovaries, cystadenomas, tumors of low malignant potential, and 405 primary ovarian carcinomas by using tissue microarray technology.

RESULTS

Overexpression of cyclin E was found in 63.2% of the samples and was associated with clear cell, poorly differentiated, and serous carcinoma (P < or = .001), high-grade tumors (P < or = .001), late-stage disease (P = .002), age older than 60 years at the time of diagnosis (P = .04), and suboptimal cytoreduction (P = .001). A high percentage of cyclin E-expressing cells was associated with a poor outcome in univariate and in multivariate analyses. In addition, cyclin E levels also reduced survival in the late-stage disease group and in patients who underwent suboptimal debulking.

CONCLUSIONS

Cyclin E was identified as an independent prognostic factor in patients with ovarian carcinoma. The accumulation of cyclin E protein may be a late event in tumorigenesis and may contribute to disease progression in these patients.

Expression of cyclin H in normal and cancerous endometrium, its correlation with other cyclins, and association with clinicopathologic parameters

Cyclins are known as regulatory proteins in cell cycle. Cyclin H is a part of cyclin H/Cdk7/Mat1 complex, which is necessary for cellular proliferation. This study was designed to investigate the correlation of cyclin H expression with tumorigenesis of the endometrium and clinicopathologic variables. Immunohistochemical staining using labeled streptavidin-biotin complex was performed on formalin-fixed, paraffin-embedded endometrial tissues of the proliferative, hyperplastic, and carcinomatous types. Immunostaining for cyclins A, B1, D1, D3, E, H, and cyclin dependent kinase 2 were evaluated. The expression of cyclins A, D1, D3, and H in hyperplasia was significantly more frequent than those of proliferative phase and less than those of endometrioid adenocarcinoma. The expression of cyclin H was correlated with lymphvascular space invasion and clinical stage in carcinoma but not with myometrial invasion, lymph node metastasis, and menopause status. The expression of cyclin H could be involved in the transformation of the endometrium into malignancy and might be a marker for more proliferative and malignant features. It might be one of the biomarkers for determining proliferative activity in endometrial hyperplasia and endometrioid adenocarcinoma.

Circadian variation in expression of G1 phase cyclins D1 and E and cyclin-dependent kinase inhibitors p16 and p21 in human bowel mucosa

AIM: To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm.

METHODS: Between January 2003 and December 2004, twenty patients who were diagnosed as suffering from primary, resectable, non-metastatic adenocarcinoma of the lower rectum, infiltrating the sphincter mechanism, underwent abdominoperineal resection, total mesorectal excision and permanent left iliac colostomy. In formalin-fixed and paraffin-embedded biopsy specimens obtained from the colostomy mucosa every six hours (00:00, 06:00, 12:00, 18:00 and 24:00), we studied the expression of G₁ phase cyclins (D₁ and E) as well as the expression of the G₁ phase cyclin-dependent kinase (CDK) inhibitors p16 and p21 as indicators of cell cycle progression in colonic epithelial cells using immunohistochemical methods.

RESULTS: The expression of both cyclins showed a similar circadian fashion obtaining their lowest and highest values at 00:00 and 18:00, respectively (P< 0.001). A circadian rhythm in the expression of CDK inhibitor proteins p16 and p21 was also observed, with the lowest levels obtained at 12:00 and 18:00 (P< 0.001), respectively. When the complexes cyclins D₁ - p21 and E - p21 were examined, the expression of the cyclins was adversely correlated to the p21 expression throughout the day. When the complexes the cyclins D₁ - p16 and E - p16 were examined, high levels of p16 expression were correlated to low levels of cyclin expression at 00:00, 06:00 and 24:00. Meanwhile, the highest expression levels of both cyclins were correlated to high levels of p16 expression at 18:00.

CONCLUSION: Colonic epithelial cells seem to enter the G₁ phase of the cell cycle during afternoon (between 12:00 and 18:00) with the highest rates obtained at 18:00. From a clinical point of view, the present results suggest that G₁-phase specific anticancer therapies in afternoon might maximize their anti-tumor effect while minimizing toxicity.

Cyclin E as molecular marker in the management of breast cancer: a review

Over the past decade numerous molecular markers have been identified that may play a role in breast carcinogenesis and prognosis. The most commonly used markers in clinical practice are the estrogen receptor, progesterone receptor and HER-2/neu. Recent studies found cyclin E to be a promising prognostic indicator in breast cancer and examined its potential as a target for therapy. Further studies demonstrated that cyclin E levels were periodic during the cell cycle, with levels of protein peaking in the G1 phase. This peak in cyclin E levels also correlated with maximum enzymatic function of the cyclin E-cdk2 complex, suggesting a critical role of cyclin E in regulating G1 to S-phase transition. Studies examining the relevance of cyclin E alterations in breast cancer have shown gene amplifications in some breast cancer cell lines, data that provide strong support for the role of cyclin E in breast carcinogenesis. It is believed that the most significant cyclin E alteration is post-translational cleavage of full-length cyclin E into low molecular weight forms that are hyperactive compared to the 50-kDa, full-length protein and correlate with increasing stage and grade of breast cancer. The role of cyclin E in the prognosis and therapy of breast cancer is reviewed according to recent publications.

The unfolded protein response affects neuronal cell cycle protein expression: implications for Alzheimer's disease pathogenesis

Alzheimer's disease (AD) is characterized by the accumulation and aggregation of misfolded proteins. The presence of misfolded proteins in the endoplasmic reticulum (ER) triggers a cellular stress response called the unfolded protein response (UPR). Previously, we have shown that the UPR is activated in AD neurons. In actively dividing cells, activation of the UPR is accompanied by decreased cell cycle protein expression and an arrest in the G1 phase of the cell cycle. Aberrant expression of cell cycle proteins has been observed in post mitotic neurons in AD and is suggested to be involved in neurodegeneration. In this study we show that the protein levels of BiP/GRP78, an ER-stress marker, is increased in Braak stages B and C for amyloid deposits. This is in contrast to the levels of cell cycle markers cyclin D1, cyclin E and phosphorylated retinoblastoma protein (ppRb) which are decreased in Braak stage C compared to Braak stage A for amyloid deposits. In addition, we report a negative correlation between neuronal expression of ppRb and expression levels of BiP/GRP78 in control and AD cases. Activation of the UPR in neuronal cells induces changes in cell cycle protein expression similar to these observed in AD brain. ER stress inducers tunicamycin and thapsigargin down-regulate cell cycle proteins ppRb and cyclin D1 in differentiated neuroblastoma cells. In contrast, protein levels of p27, a cyclin dependent kinase inhibitor, are increased after induction of ER-stress using tunicamycin. These data suggest that activation of the UPR affects cell cycle protein expression in neurons during neurodegeneration in AD.

Tumor-specific hyperactive low-molecular-weight cyclin E isoforms detection and characterization in non-metastatic colorectal tumors

PURPOSE

Several molecules involved in cancer biology have been studied as potential prognostic markers. Recently, overexpression of cyclin E and its low-molecular-weight (LMW) isoforms has been reported to be the most prominent prognostic marker in breast cancer, surpassing proliferation index, ploidy, and axillary nodal involvement. Furthermore, cyclin E and p53 are considered the main factors controlling the euploid equilibrium in human cells. We investigated the status of cyclin E and p53 in cell lines and tissue samples of colorectal cancer, one of the leading causes of death from a tumor in the Western world.

EXPERIMENTAL DESIGN

We analyzed colorectal cancer cells, from established cell lines and patient specimens, to determine the protein levels of cyclin E and p53, and to detect p53 and APC mutations, microsatellite and chromosome instability. In addition, we assessed the presence of cyclin E LMW isoforms and their enzymatic activity.

RESULTS

Colorectal cancer cells expressed hyperactive LMW forms both in vitro and in vivo. These tumor-specific isoforms are correlated to genomic instability even in p53-proficient cells, and represented a constant feature in the tumors analyzed.

CONCLUSIONS

In colorectal cancer, the formation of cyclin E LMW forms is an early event leading to DNA-damage checkpoint-independent proliferation. Collectively, our results provide evidence that evaluation of LMW forms could represent a novel tool in the molecular characterization of colorectal tumors aimed at identifying sensitive prognostic factors and uncovering subsets of high-risk patients within the traditional categories.

MDM2 protein expression is a negative prognostic marker in breast carcinoma

The protein encoded by the MDM2 oncogene inhibits the function of p53, leading to increased cell growth, avoidance of apoptosis, tolerance of genetic instability, and resistance to chemotherapy. The present study was performed to evaluate the relationship between MDM2 protein expression and survival in breast carcinoma. Two series of cases were used in this study: the first to identify the cutoff to be used in the interpretation of MDM2 immunostaining and perform preliminary survival analysis, and a second, independent series, to validate the findings from the first series and to perform multivariate analysis. For both series, archival sections of tissue microarrays were stained with anti-MDM2 antibody (NeoMarkers, Fremont, CA, USA) and MDM2 staining intensity was scored semiquantitatively. In the first series, 49 of 362 (14%) interpretable cases were positive for MDM2 expression, with 35 (10%) showing weak positivity and 14 (4%) strong positivity. Patients with MDM2-positive tumours had a significantly worse disease-specific survival than patients with MDM2-negative tumours (P=0.0022, 10-year DSS 61% (95% CI: 45-73) vs 73% (95% CI: 67-77)). No significant difference in survival was observed between patients with strongly and weakly MDM2-positive tumours (P=0.3). Accordingly, in the independent validation series weak and strong MDM2 positivity were combined and considered to be MDM2 positive. MDM2 expression was seen in 230/1747 (13%) interpretable cases in this series, with a significant difference (P<0.0001) in DSS between MDM2-negative and MDM2-positive cases (10 year DSS 58% (95% CI: 51-64) vs 73% (95% CI: 70-75)). MDM2 was an independent prognostic marker (HR=1.35, P=0.02) in a Cox regression model including MDM2 expression, tumour grade, nodal status, ER status and tumour size. Immunohistochemical studies of MDM2 in more than 2000 breast carcinomas show that MDM2 is an independent negative prognostic marker.

Dehydroepiandrosterone causes hyperplasia and impairs regeneration in rat liver

DHEA, a steroid of the adrenal gland, is a non-genotoxic hepatocarcinogen of the peroxisome proliferator type in rodents. However, DHEA also exerts anti-carcinogenic effects by reducing the number and proliferation of preneoplastic and neoplastic lesions induced by N-nitrosomorpholine. The mechanism underlying this growth-modulating effect is unclear, and no data are available on DHEA effects on normal liver. Here, we show that DHEA is a liver mitogen, increasing proliferation in rat liver after 3 days of treatment (100 mg/kg body weight per day) as indicated by significantly enhanced expression of cyclin E, PCNA and Ki-67 and an elevated number of mitotic figures. Histological observation of the liver and biochemical evaluation of serum transaminases and bilirubin did not reveal any evidence for cell death, demonstrating that increased proliferation was not due to liver damage. After 2 weeks of DHEA-treatment, proliferation parameters returned to control values and, after 4 weeks, cyclin E and Ki-67 were even lower than in controls. To study the DHEA effect on regenerating liver, we performed partial hepatectomy (PHx) on rats pretreated for 4 weeks with DHEA and analyzed the kinetics of the cell cycle. DHEA-treatment delayed the entry of hepatocytes into G1 phase by about 6 h indicated by a later rise in Ki-67 and cyclin E expression. Reduced STAT-3 activation before G1-phase entry indicates an impaired recruitment of hepatocytes to regenerative proliferation in DHEA-treated livers. The rise in proliferation observed after PHx in DHEA-treated livers was more flat and, in contrast to controls, did not show a peak value within the first 35h as indicated by Ki-67, PCNA, cyclin E and BrdU-incorporation levels in hepatocytes. In conclusion, the results show that DHEA acts as a mitogen in rat liver but reduces the regenerative capacity of the liver.

The ribonucleotide reductase subunit M2B subcellular localization and functional importance for DNA replication in physiological growth of KB cells

Ribonucleoside diphosphate reductase (EC 1.17.4.1) (RR) is a potential target for antineoplastic agents due to its crucial role in DNA replication and repair. The expression and activity of RR subunits are highly regulated to maintain an optimal dNTP pool, which is required to maintain genetic fidelity. The human RR small subunit M2B (p53R2) is thought to contribute to DNA repair in response to DNA damage. However, it is not clear whether M2B is involved in providing dNTPs for DNA replication under physiological growth conditions. Serum starvation synchronized studies showed that a rapid increase of M2B was associated with cyclin E, which is responsible for regulation of G(1)/S-phase transition. A living cell sorting study that used KB cells in normal growth, further confirmed that M2B increased to maximum levels at the G(1)/S-phase transition, and decreased with DNA synthesis. Confocal studies revealed that M2B redistributed from the cytoplasm to the nucleus earlier than hRRM2 in response to DNA replication. Nuclear accumulation of M2B is associated with dynamic changes in dNTP at early periods of serum addition. By using M2B-shRNA expression vectors, inhibition of M2B may result in growth retardation in KB cells. We conclude that M2B may translocate from the cytoplasm into the nucleus and allow dNTPs to initiate DNA synthesis in KB cells under physiological conditions. Thus, our findings suggested that M2B might play an important role for initiating DNA replication of KB cells in normal growth.

Standard and quantitative analysis of cyclin E threshold by cyclin E/DNA multiparameter flow cytometry

The threshold of cyclin E expression at G1/S boundary is a characteristic feature of cell cycle progressing. In this study, we tried to develop a quantitative approach to analyze cyclin E threshold by multiparameter flow cytometry. The expression of cyclin E in exponentially growing MOLT-4 cells was detected under different photomultiplier tube (PMT) voltages by cyclin E/DNA multiparameter flow cytometry. Additionally, cyclin E was detected in cells which were treated with caffeine and cycloheximide (CHX) under the same PMT voltage. Moreover, the expression of cyclin E in MOLT-4 cells was compared with that in JURKAT cells. Cyclin E threshold was quantified by formula B2/AxC (A, B, C indicates the minimum, threshold, and maximum of cyclin E fluorescence intensity, respectively). Results showed that in MOLT-4 cells, cyclin E threshold calculated by formula B2/AxC was invariable under different PMT settings. It was decreased in cells treated with caffeine and remained changeless in cells treated with cycloheximide. Cyclin E threshold in JURKAT cells was much lower than that in MOLT-4 cells. It was suggested that Formula B2/AxC we firstly set up could be used to analyze cyclin E expression threshold quantitatively.

Differential expression of cyclins A, B1, D3 and E in G1 phase of the cell cycle between the synchronized and asynchronously growing MOLT-4 cells

The use of 'double-thymidine block' was the first widely accepted method for inducing cell synchrony and remains one of the most effective and frequently used techniques for analyzing the cell cycle today. While thymidine is in itself an inhibitor of DNA replication, thymidine blocks are typically used to generate cell synchrony at the G1/S boundary. We have previously presented the first evidence that shows the growth imbalance and altered expression levels of cyclins A, B1, D3 and E in MOLT-4 cells synchronized in the cell cycle by thymidine. The major objective of the present study was to compare the levels of cyclins A, B1, D3 and E in G1 phase of the cell cycle between synchronized and unperturbed asynchronously growing human lymphocyte leukemia MOLT-4 cells. Here, we demonstrate that the sorted, asynchronously growing MOLT-4 cells had considerably lower levels of cyclins A, B1, D3 and E than their counterparts of the cells arrested in G1/S phase, as assessed by flow cytometry. In addition, we confirmed these results by using post-sorting Western blotting, a new method we recently developed for examining protein expression in specific phases of sorted, synchronized or asynchronously growing cells. Our findings revealed that the levels of cyclins D3 and E in the asynchronously growing MOLT-4 cells were significantly lower than those in synchronized cultures. Interestingly, protein expression levels of cyclins A and B1 in the asynchronously growing MOLT-4 cells were barely measurable, suggesting that these proteins were either not expressed or under detectable levels. These studies indicate that our synchronization protocol may have disturbed cell proliferation and metabolism as evidenced by significant differences in the expression of cyclins between asynchronously growing and synchronized cells, and further suggest that the levels of cyclins A, B1, D3 and E in synchronized cultures cannot represent those in unperturbed, asynchronously growing cells. Thus, it appears that thymidine-treated, synchronized cells may not be suitable experimental models for the study of normal cell cycle.

Different growth capacity between infant and adult mouse hepatocytes in vitro correlates to the cyclin D1 level without relation to oxidative DNA damage

BACKGROUND

Proliferating capacity of hepatocytes is rapidly decreased during growth into maturity, but its exact reason(s) are not well known.

METHODS

Hepatocytes isolated from infant (10-14 days old) and adult (10-13 months old) B6C3F1 mice were cultivated in the medium containing epidermal growth factor and insulin. Proliferative capacity, apoptosis, morphological changes, cell cycle proteins and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were compared between the two hepatocyte populations.

RESULTS

Although adult hepatocytes rapidly underwent cellular crisis characterized by extended morphology and multiple nuclei without proliferation, infant hepatocytes could proliferate with less crisis. Cyclin D1 was much more abundant in the infant than adult cells, but there was no difference according to the expression of cdk4, cdk2, cyclin E and cdk inhibitors (p16(Ink4) (p16), p21(Cip1/Waf1) (p21) and p27(Kip1) (p27)). 8-OHdG became high soon after cultivation, while it rapidly went down after day 2 both in the infant and adult cells.

CONCLUSIONS

The high growth capacity of infant hepatocytes in vitro was dependent on the cyclin D1 level, but there was no relation to 8-OHdG.

Expression of the cyclin-dependent kinase inhibitor p27 and its deregulation in mouse B cell lymphomas

CDKN1B (p27) regulates cell-cycle progression at the G1-S transition by suppressing the cyclin E/CDK2 kinase complex. In normal lymphocytes and most human B cell non-Hodgkin lymphomas (NHL), there is an inverse correlation between proliferative activity and expression of p27; however, a subset of NHL with high mitotic indices expresses p27, which is inactive due to sequestration in nuclear protein complexes or due to cytoplasmic retention. Our studies of mouse B cell NHL also identified cases with high proliferative activity and high levels of p27 at a surprisingly high frequency. Here, p27 was complexed with D-type cyclins 1 and 3 and with the COPS9 protein, JAB1. In addition, we found cytoplasmic sequestration following phosphorylation by activated AKT.

Differentiating high-grade cervical intraepithelial lesion from atrophy in postmenopausal women using Ki-67, cyclin E, and p16 immunohistochemical analysis

OBJECTIVE

In postmenopausal women, differentiating high-grade cervical intraepithelial neoplasia (CIN 2,3) from atrophic uterine cervical squamous epithelium histologically may pose a diagnostic challenge. Recent studies have indicated the value of using a combination of Ki-67, cyclin E, and p16 immunohistochemical analysis in recognizing CIN 2,3. In this study, we compared the staining features of Ki-67, cyclin E, and p16 in cervix specimens from postmenopausal women to distinguish CIN 2,3 from atrophy.

METHODS

Twenty-six formalin-fixed paraffin-embedded archival cervical specimens (4 biopsy, 8 laser cone, and 14 total hysterectomy samples) were selected from 25 women 50 to 80 years of age (mean = 64 years). Cases included CIN 2,3 (n = 10), atrophy (n = 9), and coexistent CIN 2,3 and atrophy (n = 6). Slides were stained with monoclonal antibodies to Ki-67, cyclin E, and p16 using the avidin-biotin-peroxidase method. Strength of staining was graded as 1+ to 3+. Pattern of staining was described as diffuse, patchy, or scattered. Ki-67 staining restricted to the basal/parabasal zone was scored as negative.

RESULTS

All CIN 2,3 cases demonstrated variable positivity for Ki-67, cyclin E, and p16. Most CIN 2,3 cases showed strong p16 (81.3%) and Ki-67 (75.0%) reactivity, while only 31.3% of them showed strong cyclin E activity. Some CIN 2,3 cases demonstrated strong p16 but weak Ki-61 and cyclin E reactivity. All atrophic epithelia were negative for p16, cyclin E, and Ki-67. In coexistent CIN 2,3 and atrophy cases, the three-antibody panel clearly demarcated the transition from benign to neoplastic epithelia.

CONCLUSION

P16 is the most valuable marker followed by Ki-67 for differentiating CIN 2,3. While cyclin E appears to add limited value on these two markers. Therefore, although the three-antibody immunohistochemical panel (p16, Ki-67, and cyclin E) can be a valuable adjunct to routine hematoxylin-eosin staining, it is also possible to use the two-antibody panel (p16 and Ki-67) to effectively distinguish CIN 2,3 from atrophy in postmenopausal women.

Placental Cadherin and the Basal Epithelial Phenotype of BRCA1-Related Breast Cancer

PURPOSE

BRCA1-related breast cancer frequently has a basal epithelial phenotype, and P-cadherin is a basal marker. We undertook a detailed evaluation of the relationship among P-cadherin, prognostic markers in breast cancer, and outcome.

EXPERIMENTAL DESIGN

This study was restricted to 292 cases of first primary invasive breast cancer diagnosed in Ashkenazi Jewish women between 1980 and 1995. All available blocks were stained for P-cadherin, and 261 were included in the final statistical analyses, including 27 germ line BRCA1 mutation carriers and 8 BRCA2 mutation carriers. Descriptive analyses were done followed by survival analyses and a Poisson regression analysis.

RESULTS

P-cadherin was present in 80 of the 261 breast cancers (31%) and was more frequently present in tumors that have a basal epithelial phenotype [i.e., high-grade, estrogen receptor- and KIP1 (p27(Kip1))-negative tumors, with expression of cytokeratin 5/6, cyclin E, TP53, and presence of BRCA1 mutations and vascular nests (all P < 0.001)]. In a univariate survival model, expression of P-cadherin was associated with a relative risk (RR) of death from breast cancer at a 10-year follow-up of 2.9 (95% confidence interval, 1.8-4.7; P < 0.0001) and was a predictor of poor univariate survival in both lymph node-negative and -positive breast cancers. In a multivariate analysis, the effect of P-cadherin levels was not independent of other basal-related markers. Multivariable interaction modeling showed that P-cadherin positivity was highly predictive of a poor prognosis in small, node-negative breast cancers (RR, 7.1; P = 0.006).

CONCLUSIONS

P-cadherin is a marker for basal-like breast cancers and is strongly associated with the presence of a BRCA1 mutation. It is an adverse prognostic factor, particularly in small, node-negative breast cancers.

Tissue microarray analysis of multiple gene expression in intestinal metaplasia, dysplasia and carcinoma of the stomach

AIMS

To study multiple gene expression patterns and their roles in the process of gastric carcinogenesis.

METHODS AND RESULTS

Using a high-throughput tissue microarray technique, 169 specimens from gastric carcinomas, precursor lesions and normal mucosa were immunostained on a series of tissue chips for p53, p21(WAF1/CIP1) cyclin E, Bcl-2, c-met and mucin 5AC expression. The overexpression of p53 was observed in 10.7% of low-grade dysplasia (LGD), 38.1% of high-grade dysplasia (HGD) and 39.6% of intestinal type gastric carcinoma (IGC). Expression of p21(WAF1/CIP1) was found in 47.6% of incomplete intestinal metaplasia (IM), 36.7% of dysplasia (Dys) and 29.5% of IGC. The overexpression of cyclin E was more frequently present in carcinomas than in Dys (P < 0.05); moreover, high-level expression (> 25% in extent) of cyclin E was observed only among IGC. Abnormal Bcl-2 expression was present in 81.0% of incomplete IM, 69.4% of Dys and 22.9% of IGC. Along with progression of the lesion, the expression of c-met increased; in contrast, mucin 5AC decreased gradually.

CONCLUSIONS

The specific expression pattern in incomplete IM was mucin 5AC+/Bcl-2+/p53-/cyclin E-, while mucin 5AC-/cyclin E+ was specific for IGC. p53 was useful for distinguishing LGD from HGD. High-level expression of cyclin E might be an indicator for malignant transformation of dysplasia.

Bringing Molecular Prognosis and Prediction to the Clinic

In the past 30 years, important advances have been made in the knowledge of breast cancer biology and in the treatment of the disease. However, the translation of these advances into clinical practice has been slow. With the advent of molecular-based medicine, it is hoped that the bridge between the bench and the bedside will continue to be shortened. Because breast cancer is a heterogeneous disease with wide-ranging subsets of patients who have different prognoses and who respond differently to treatments, the identification of patients who need treatment and the definition of the best therapy for an individual have become the priorities in breast cancer care. This article will review the crucial role of prognostic and predictive factors in achieving these goals. A critical review of classical and newer individual molecular markers, such as hormone receptors, HER2, urokinase-type plasminogen activator and plasminogen activator inhibitor 1, cyclin E, topoisomerase II, and p53, was performed, and the preliminary results obtained using the new gene expression profiling technology are described along with their potential clinical implications.

Patterns of cyclin E, retinoblastoma protein, and p21Cip1/WAF1 immunostaining in the oncogenesis of papillary thyroid carcinoma

PURPOSE

Uncontrolled cell proliferation, a hallmark of cancer, may result from an increased expression of cell cycle up-regulators, and/or from a reduced expression of cell cycle down-regulators. In the present study, we analyzed, by immunohistochemistry, the expression of a panel of three proteins: cyclin E and two cell cycle inhibitors, p21(Cip1/WAF1) and retinoblastoma protein (pRb) product, in different stages of papillary thyroid carcinomas (PTC).

EXPERIMENTAL DESIGN

We investigated immunostaining patterns of the proteins in question in 51 resected PTC in pathologic stages, ranging from pT(1a) to pT(4), taking into consideration their relation to clinicohistopathologic factors.

RESULTS

We observed a significant, progressive loss of expression of p21(Cip1/WAF1) with advancing tumor grade. The differences reached values of significance between pT(1a) [papillary thyroid microcarcinomas (PMC)] and pT(2) and between PMC and pT(4) stages of PTC. pRb presented a similar immunostaining pattern to that of p21(Cip1/WAF1) and the differences reached values of significance between pT(1a) and pT(2), and between PMC and pT(4) stages of PTC. The results of cyclin E immunostaining corresponded to our recently published result, and a negative correlation was observed between the immunostaining index of cyclin E and pRb.

CONCLUSIONS

The results of the present study suggest that cyclin E expression and suppression of pRb and p21(Cip1/WAF1) may be characteristic patterns of immunostaining for PTC with a tendency to early metastasizing. If our results are confirmed in a larger study, the diagnostic panel, constructed of the antibodies against these proteins, may become a valuable tool in predicting the metastatic potential in PTC.

The molecular basis of tamoxifen induction of mouse uterine epithelial cell proliferation

Tamoxifen, a selective estrogen modulator (SERM) that has found clinical utility in the treatment of breast cancer, is an antagonist in the breast and an agonist in the uterus. These agonist actions in the uterus lead to an increased risk of endometrial cancer. In this study in mice we have analyzed the mechanism of action of tamoxifen in inducing cell proliferation in the uterine luminal epithelia. Tamoxifen induces a wave of DNA synthesis in these epithelial cells with kinetics similar to those seen after 17beta-estradiol (E(2)) treatment. However, by these criteria of mitogenicity, it is much less potent and never achieves full estrogenicity. This uterine epithelial cell proliferation is preceded by the mobilization of cyclin D1 from the cytoplasm to the nucleus which, together with CDK4, phosphorylates members of the Rb-retinoblastoma family of proteins, pRb and p107. Subsequent to this initial nuclear accumulation of cyclin D1, cyclin E and then cyclin A are induced that, together with the activation of CDK2, results in enhanced cyclin E- and cyclin A-dependent CDK2 kinase activity and further phosphorylation of pRb and p107. These actions of tamoxifen parallel those of E(2). Tamoxifen also induced the classical estrogen water imbibition response. However, in this it was more potent, producing a maximal response at doses that do not affect DNA synthesis. This suggests that the uterotropic response is not an accurate predictor of the compound's hyperplasia responses. We can conclude that, in its effects on proliferation, tamoxifen acts as a classical impeded estrogen and this suggests that the AF-1 transcription activation domain of the estrogen receptor that is activated upon both E(2) and tamoxifen binding to this receptor regulates these responses in the uterus.

Aberrant expression of cell cycle regulators in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma

The characteristic Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma, although highly positive for proliferation markers, do not accumulate to excessive cell numbers. These cells are characterized by abortive mitotic cycles, leading to multinucleation or cell death in mitosis. We have previously described high expression of G1-phase cyclins in classical Hodgkin's lymphoma, which could explain the high percentage of cells staining for proliferation markers. To further our understanding of proliferation control in classical Hodgkin's lymphoma, we extended our immunohistochemical analysis to the main S-phase cyclin, cyclin A, and its regulators p21CIP1 and p27KIP1. Expression of proliferating cell nuclear antigen (PCNA) was used as an additional marker for cells being in either S- or G2-phase. In 47% (112/239) of classical Hodgkin's lymphoma cases p21CIP1 was detected within a mean frequency of 15% positive Hodgkin's and Reed-Sternberg cells per case. Similarly, 47% (116/249) of the cases stained positively for p27KIP1 with a mean frequency of expression in Hodgkin's and Reed-Sternberg cells of 12%. In contrast, 90% of the cells in all 246 evaluable classical Hodgkin's lymphoma cases were positive for PCNA. In addition, 98% of Hodgkin's and Reed-Sternberg cells in 99% (250/253) of the cases stained strongly positive for cyclin A. These findings further corroborate the hypothesis that Hodgkin and Reed-Sternberg cells exhibit a disturbed cell cycle with an abnormally short or even absent G1-phase. In contrast to other tumors, expression of PCNA or cyclin A had no prognostic value for patient survival.

Cyclin E, p27 and mutant p53 do not predict the prognosis in AJCC stage II colorectal carcinomas

BACKGROUND/AIMS

Carcinogenesis is characterized by the abnormal regulation of cell cycle. The abnormal expression of the regulators of cell cycle may be related to the prognosis. Since the clinical significance of the expression of the three proteins in colorectal carcinomas is still controversial, we evaluated the prognostic value of the expression of cyclin E, p27 and mutant p53 in stage II colorectal cancer.

METHODS

The expression levels of cyclin E, p27 and mutant p53 proteins in 41 patients with stage II colorectal carcinomas were analyzed by immunohistochemistry.

RESULTS

In the univariate analysis, the level of CEA at diagnosis was associated with disease relapse. In the multivariate analysis, the clinicopathological variables such as age, gender, site of primary tumor, tumor size, state of tumor differentiation and preoperative plasma CEA level were not associated with disease relapse. When Kaplan-Meier survival curves were constructed to determine the prognosis, cyclin E, p27 and mutant p53 expressions did not predict poor prognosis.

CONCLUSIONS

Our results suggested that the expression of cyclin E, p27 and mutant p53 proteins did not predict the clinical outcome in the stage II colorectal carcinomas.

Cyclin E Amplification and Overexpression in Clear Cell Adenocarcinoma of the Ovary

OBJECTIVE

The purpose of this study is to compare DNA, mRNA and protein levels of the cyclin E between clear cell (CC) and serous (SC) ovarian carcinomas, and evaluate the relationship between cyclin E and p53 status.

METHOD

We examined the DNA, mRNA and protein levels of cyclin E and the protein level of p53 in 44 CCs and 39 SCs using microdissected tissues.

RESULTS

Relative cyclin E mRNA expression was significantly higher in CC (3.62, 95% CI, 2.24-4.99) than in SC (1.75, 95% CI, 1.05-2.45; p = 0.0098). The percentage of positive nuclear staining of cyclin E was significantly higher in CC (48.3, 95% CI, 40.4-56.1) than SC (25.3, 95% CI, 17.4-33.3; p = 0.0001). The mRNA and protein expression of cyclin E was significantly correlated (r = 0.66, p < 0.0001). However, the correlation between relative DNA copy number and relative mRNA expression was not significant (r = -0.063; p = 0.66). Percentage of positive nuclear staining of cyclin E was significantly higher in p53 positive cases (51.8, 95% CI, 40.0-63.5) than p53 negative cases (36.2, 95% CI, 28.2-44.2; p = 0.028).

CONCLUSIONS

Cyclin E expression is significantly higher in CC than in SC. Cyclin E expression is significantly related with p53 positivity.

Cyclin D1, cyclin E, and p21 have no apparent prognostic value in anal carcinomas treated by radiotherapy with or without chemotherapy

The purpose of this study was to assess the potential prognostic and/or predictive value of the expression of cyclin D1, cyclin E, and p21 protein in a series of 98 anal carcinomas (T1–4, N0–3) treated by radiotherapy with (51) or without (47) chemotherapy in one institution. Correlation with Mib1 index and p53 expression was also investigated. Median follow-up for surviving patients was 124 months (range: 30–266). Immunohistochemical staining was performed on pretreatment biopsies, applying a standard ABC technique for cyclin D1 (clone DSC6, DAKO, 1 : 300), cyclin E (clone 13A3, Novocastra, 1 : 100), p21^WAF/CIP1 (clone SX118, DAKO, 1 : 50), p53 (clone DO7, DAKO, 1 : 200), and Mib1 (Ki-67, Dianova, 1 : 20). Tumours were classified into low- or high-expression groups according to the expression level of the protein considered. High expression was found in 51% of tumours for cyclin E, in 33.7% for cyclin D1, and in 65% for p21. None of those factors were significantly associated with clinical variables such as advanced T or N categories. In a monovariate analysis, advanced T and N categories and longer overall treatment time were the only variables that correlated significantly with low rate of local control (LC) and disease-free survival. However, in a subgroup analysis, high p21 expression correlated with a trend for significantly higher 5-year LC (87 vs 68%, P=0.07) in the N0 patients. The results of this study suggest that the cell-cycle proteins investigated are unlikely to be clinically useful in predicting treatment response or prognosis in patients with anal carcinomas.