Cyclin-D1 expression in node-positive (N+) and node-negative (N-) infiltrating human mammary carcinomas

CCND1 mRNA Overexpression is Highly Related to Estrogen Receptor Positivity but not to Proliferative Markers in Primary Breast Cancer

To elucidate the role of CCND1 alterations in sporadic breast cancer we investigated the possible link between CCND1 mRNA levels versus estrogen-receptor (ER) status and a proliferation marker, S-phase fraction (SPF), measured by flow cytometry. CCND1 expression was quantified by means of real-time quantitative RT-PCR in a well-characterized series of 33 primary breast cancer patients. Eighteen tumors (54.5%) showed CCND1 overexpression ranging from 3.3 to 29.5 times the level observed in normal breast tissue. Seventeen (94.4%) of the 18 cases with CCND1 overexpression were ER-positive compared to seven (46.7%) of the 15 cases with normal CCND1 expression (p=0.0074). CCND1 overexpression was independent of SPF and DNA-ploidy status. These data suggest that the CCND1 gene does not act as an oncogene responsible for more rapid cell proliferation in breast cancer, but could be involved in the regulation of hormone sensitivity associated with ER.

CyclinD1 and p57kip2 as biomarkers in differentiation, metastasis and prognosis of gastric cardia adenocarcinoma

Objective

This study aims to investigate the expression and significance of p57^kip2 and cyclinD1 in gastric cardia adenocarcinoma (GCA). p57^kip2 is a negative regulator in the cell cycle. On the contrary, cyclinD1 is a positive regulator of cell cycle progression.

Methods

Thirty-two cases of GCA tissues and adjacent non-cancerous tissues were collected for this study. Immunohistochemistry and fluorescence qualitative PCR was used to determine the level of p57^kip2 and cyclinD1 in GCA and its adjacent non-cancerous tissues. Furthermore, the correlation between the mRNA/protein and GCA clinical pathologic parameters were analyzed, and the relationship of p57^kip2 and cyclinD1 in GCA were also evaluated.

Results

The expression of p57^kip2 significantly lower in GCA (P = 0.036), and there was a significant correlation in the different degrees of differentiation (P < 0.05). Furthermore, median survival time was 41 months for patients with high mRNA expression of p57^kip2. This was longer compared to patients with low mRNA expression of P57^kip2 (37 months, X² = 4.788, P = 0.029).The expression of cyclinD1 was significantly higher in GCA(P = 0.002), and was significant correlated to clinical stage(P<0.05). Median survival time was 34 months in patients with high mRNA expression of cyclinD1, which was shorter than in patients with low expression of cyclinD1 mRNA (41 months, X² = 4.071, P = 0.044). The protein expression of p57^kip2 was not correlated to the protein expression of cyclinD1 (P = 0.55).

Conclusion

The expression of p57^kip2 and cyclinD1 are likely to suppress or promote the tumorigenesis and progression of GCA.

Association among the expression of β-catenin, cyclin D1 and estrogen receptor-β in human breast cancer

β-catenin, cyclin D1 and estrogen receptor (ER)-β are closely associated with the pathogenesis of breast cancer. In the present study, tissue samples were collected from 226 patients with breast cancer. Subsequently, immunohistochemical analysis was performed to detect the expression of β-catenin, cyclin D1 and ER-β, and the Kaplan-Meier method was used for survival analysis. The abnormal expression rate of β-catenin was 75.2%, while the cyclin D1 positive expression rate was 77.0% and the ER-β positive expression rate was 43.4%. In the tissue samples exhibiting abnormal expression of β-catenin, the positive expression rate of cyclin D1 (85.9%) was significantly higher compared with the samples that expressed β-catenin normally (50.0%). Furthermore, the positive expression rate of ER-β (35.7%) in the β-catenin normal expression tissues was significantly lower compared with that in the β-catenin abnormal expression tissues (45.9%). In the tissues with positive cyclin D1 expression, the positive expression rate of ER-β (48.4%) was significantly higher compared with the cyclin D1 negative expression samples (26.9%). In addition, patients with normal expression of β-catenin and positive expression of cyclin D1 exhibited longer tumor-free survival times. Therefore, an association exists among the abnormal expression of β-catenin and the positive expression of cyclin D1 and ER-β, which may contribute to the development of breast cancer.

Cyclin E correlates with manganese superoxide dismutase expression and predicts survival in early breast cancer patients receiving adjuvant epirubicin-based chemotherapy

Anthracycline-based chemotherapy represents a milestone in the treatment of breast cancer. We previously demonstrated in an in vitro model that cyclin E overexpression is associated with increased expression of manganese superoxide dismutase (MnSOD) and resistance to doxorubicin. In the present study, immunohistochemical expression of cyclin E and MnSOD was evaluated in 134 early breast cancer patients receiving adjuvant epirubicin-based chemotherapy regimens containing epirubicin. Both parameters were correlated with the available clinicopathological parameters and with the outcome of patients. Overexpression of cyclin E and MnSOD was detected in 46 (34.3%) and 56 (41.8%) patients, respectively, and expression levels of the two proteins were related. Disease-free and alive patients displayed a lower mean percentage of cyclin E-expressing cells than relapsed and dead patients, respectively. Kaplan-Meier survival analysis demonstrated a significant separation between high versus low cyclin E-expressing tumors in terms of overall survival (P = 0.038 by log-rank). Similar results were obtained considering the subset of node-negative patients separately. No significant relationship with patient outcome was observed for MnSOD expression levels. At multivariate analysis cyclin E failed to demonstrate an independent prognostic value. In conclusion, the results of the present study support previous evidence that increased cyclin E expression is associated with higher MnSOD expression levels and poorer outcome, at least as evaluated in terms of overall survival. Further studies are warranted to evaluate the usefulness of cyclin E as a prognostic marker to identify breast cancer patients at higher risk of death from the disease when treated with adjuvant anthracycline-based therapy.

DNA flow cytometry of canine mammary tumors: comparative aspects with human breast tumors

Flow cytometric analysis of DNA content was performed on 28 samples of canine mammary tumors. Nine of them were benign and 19 were malignant. All benign tumors and 11 malignant tumors (57.9%) were diploid (P<0.05). Form the aneuploid tumors, five (26.3%) were hyperdiploid, one (5.3%) hypodiploid, one (5.3%) near triploid and one (5.3%) multiploid. The analysis of the expression of the markers PR and CD31 revealed a significant difference between diploid and aneuploid tumors (P<0.05). The immunoreactivity of PR was higher in diploid tumors, while the immunoreactivity of CD31 was stronger in aneuploid tumors. No difference between the markers MIB-1, c-erbB2, p53 and Cyclin D1 was observed (P>0.05). Using the flow cytometry analysis and immunohistochemistry, it was found a close relationship between aneuploidy and malignant character of neoplasias, progesterone receptor (PR) negative immunostaining and higher microvases density. No correlation between DNA content and S phase or immunoreactivity for the markers MIB-1, p53, c-erbB2 and Cyclin D1 was observed.

Expression of estrogen receptor-alpha and Ki67 in relation to pathological and molecular features in early-onset infiltrating ductal carcinoma

Estrogen causes breast cancer by triggering proliferation via an estrogen receptor (ER)-mediated mechanism. However, paradoxically, ER alpha, one of the two known ER subtypes, and the proliferation marker, Ki67, are not usually expressed in the same breast tumor. To explore whether ER alpha-positive tumors and proliferating (Ki67-positive) tumors have different tumorigenic characteristics, we performed an immunohistochemical study on 74 early-onset infiltrating ductal carcinomas of the breast. To test this hypothesis, we examined whether ER alpha-positive and Ki67-positive tumors showed differences in (i) pathological grade, (ii) three indices of tumor grade (tubule formation, nuclear pleomorphism, and mitotic number), and (iii) expression of important proteins implicated in breast tumorigenesis (cyclin D1, ErbB2, ATM, BRCA1, Rb, p53, and p21). The results of the multigenic analysis showed that ER alpha and Ki67 were the only two important markers significantly and independently associated with tumor grade, consistent with the above hypothesis. ER alpha-positive, Ki67-negative tumors frequently displayed a low tumor grade (i.e. being well differentiated), whereas Ki67-positive, ER alpha-negative tumors were more likely to exhibit a high tumor grade. In addition, positive ER alpha expression (46 of 74 cases, 62%) correlated well with positive cyclin D1 expression (p < 0.005), less nuclear pleomorphism (p < 0.001), and a low mitotic count (p < 0.005), whereas positive Ki67 expression (36 of 74 cases, 49%) correlated with reduced BRCA1 expression (p < 0.01) and high mitotic activity (p < 0.01). These findings suggest that the expressions of ER alpha and Ki67 might be involved in distinct pathological and molecular features during breast cancer development.

Protein Expression Profiling Identifies Subclasses of Breast Cancer and Predicts Prognosis

Breast cancer is a heterogeneous disease whose evolution is difficult to predict by using classic histoclinical prognostic factors. Prognostic classification can benefit from molecular analyses such as large-scale expression profiling. Using immunohistochemistry on tissue microarrays, we have monitored the expression of 26 selected proteins in more than 1,600 cancer samples from 552 consecutive patients with early breast cancer. Both an unsupervised approach and a new supervised method were used to analyze these profiles. Hierarchical clustering identified relevant clusters of coexpressed proteins and clusters of tumors. We delineated protein clusters associated with the estrogen receptor and with proliferation. Tumor clusters correlated with several histoclinical features of samples, including 5-year metastasis-free survival (MFS), and with the recently proposed pathophysiologic taxonomy of disease. The supervised method identified a set of 21 proteins whose combined expression significantly correlated to MFS in a learning set of 368 patients (P &lt; 0.0001) and in a validation set of 184 patients (P &lt; 0.0001). Among the 552 patients, the 5-year MFS was 90% for patients classified in the “good-prognosis class” and 61% for those classified in the “poor-prognosis class” (P &lt; 0.0001). This difference remained significant when the molecular grouping was applied according to lymph node or estrogen receptor status, as well as the type of adjuvant systemic therapy. In multivariate analysis, the 21-protein set was the strongest independent predictor of clinical outcome. These results show that protein expression profiling may be a clinically useful approach to assess breast cancer heterogeneity and prognosis in stage I, II, or III disease.

Prognostic value of combined analysis of cyclin D1 and estrogen receptor status in breast cancer patients

The amplification of cyclin D1, located on chromosome 11q13, in breast cancer patients has been found to be associated with reduced relapse-free and overall survival; however, there still exists strong controversy about these findings. In order to evaluate the prognostic value of cyclin D1 and other prognostic variables in human breast cancers, we have assessed estrogen receptor (ER) status, cyclin D1, c-erbB2 and p53 overexpression in 175 primary breast carcinomas, and investigated the relationships of prognostic variables to the patient clinical outcome and the association between cyclin D1 overexpression and other prognostic variables. There was some degree of variability in staining intensities and proportions within the same tumor. The overexpression of both cyclin D1 and ER revealed a significantly prolonged survival in univariate analysis (P = 0.020). Among the various prognostic variables, distant metastasis showed a statistically significant association with overall survival. A significant correlation was observed between cyclin D1 overexpression and small size of the primary tumor (P = 0.031), low Bloom and Richardson's histological grade (P = 0.001), and positive ER status (P = 0.000). In contrast to what was previously expected, the present study suggests that the overexpression of cyclin D1 has a tendency to have a positive clinical outcome and a potential role in identifying a subset of patients predicting a good prognosis, particularly when ER is coexpressed.

[CCND1 oncogene amplification and cellular DNA content in squamous cell carcinomas of the head and neck]

Cyclin D1 protein (encoded by the CCND1 gene) contributes to the progression of the cell cycle in the G1/S checkpoint. Cyclin D1 overexpression (for instance as a consequence of CCND1 amplification) might result in loss of control over genetic damage at this point and in an accumulation of chromosomal aberrations. In this work we analyze whether CCND1 amplification is associated with a higher incidence of alterations in cellular DNA content. 31 squamous cell carcinomas of the head and neck were studied. CCND1 amplification was determined by polymerase chain reaction. Cellular DNA content was determined by flow cytometry. CCND1 amplification was found in 6 (19%) cases. Thirteen (42%) cases were diploid and 18 (58%) were aneuploid. Two (33%) of the 6 cases with CCND1 amplification were aneuploid compared with 16 (64%) of the cases without CCND1 amplification (P = 0.36). We conclude that CCND1 amplification is not associated to a higher incidence of chromosomal aberrations in squamous cell carcinomas of the head and neck.

Cytologic evaluation of cyclin D1 expression in primary breast carcinoma

BACKGROUND

Preoperative assessment of the biologic characteristics of primary breast carcinoma is important because neoadjuvant medical therapy is being used increasingly. In the current study, the authors attempted to evaluate the validity of cyclin D1 assay in fine-needle aspiration (FNA) samples from patients with primary breast carcinoma.

METHODS

FNA samples were obtained prior to therapy and multiple slides were stored at -80 degrees C for subsequent immunocytochemical analysis (ICA). ICA for cyclin D1 protein was performed on FNA samples from 51 breast carcinoma patients and 20 samples from patients with benign breast disease. In 45 breast carcinoma patients who had undergone surgery, sections were taken from paraffin blocks and stained by ICA for cyclin D1 validation. Possible correlations between cyclin D1 expression in the FNA samples and the biologic data of the patients also were analyzed.

RESULTS

Cyclin D1 expression was detected in 37 FNA samples from 51 breast carcinomas (72.5%) whereas expression of cyclin D1 was detected in 8 FNA samples from 20 patients with benign breast disease (40%). In histologic sections after surgery, 26 cases of breast carcinoma (65%) showed a positive reaction to cyclin D1. Concordance for the presence of cyclin D1 between FNA samples and histologic samples was 75%. Cyclin D1 expression was high in patients with the tumors that expressed estrogen receptor (ER) (30 of 34 vs. 5 of 11; P = 0.028) and progesterone receptor (PR) (33 of 38 vs. 2 of 7; P = 0.007). There was no significant relation found between cyclin D1 expression and tumor size or lymph node metastasis. Cyclin D1 expression within invasive ductal carcinoma was observed in > 80% of low or intermediate nuclear grade tumors but its expression decreased to 61.5% (8 of 13 cases) in tumors with high nuclear grade (P = 0.023). All 14 breast carcinomas in which the S-phase fraction was </= 15% showed a high degree of cyclin D1 expression whereas 4 of 6 tumors (66.7%) in which the S-phase fraction was > 15% showed cyclin D1 expression. Cyclin D1 expression was found to be correlated inversely with proliferative activity in breast carcinoma (P = 0.023).

CONCLUSIONS

The results of the current study show that cyclin D1 expression can be measured by ICA in FNA samples with reasonable concordance with the results of histologic section. Cyclin D1 expression was found to be associated with ER/PR status and cell differentiation. The results of the current study indicate that the measurement of novel molecular markers could be performed adequately in FNA samples as well as in histologic sections.

Inhibition of human breast cancer cell growth by blockade of the mevalonate-protein prenylation pathway is not prevented by overexpression of cyclin D1

Overexpression of the cyclin D1 (CCND1) gene, encoding a downstream effector of mitogenic signals that plays a central role in G1 phase progression, is often found in cancerous cells. In sporadic breast cancer (BC), this is one of the most frequent and early genetic lesions identified so far, found in more than 50% of the tumors. Inhibitors of the mevalonate/protein prenylation pathway belong to a new family of cancer therapeutic agents that act by blocking intracellular mitogenic signal transduction pathways, thereby preventing expansion of pre-cancerous foci and inhibiting growth of transformed cells. It is not known at present whether constitutively high intracellular levels of cyclin D1 might interfere with the cytostatic actions of mevalonate/protein prenylation inhibitors. This possibility was investigated here by assessing the cell cycle effects of Simvastatin, a non-toxic upstream inhibitor of the mevalonate pathway, on human BC MCF-7 cells expressing either normal or enhanced levels of cyclin D1 from of a stably transfected, tet-inducible expression vector. Results show that constitutive overexpression of this protein, such as that found in sporadic BCs, does not influence the growth inhibitory effects of Simvastatin in vitro. In addition, D1-overexpressing embryo fibroblasts were also found to be responsive to the cell cycle effects of mevalonate/protein prenylation pathway blockade, further suggesting that high intracellular levels of cyclin D1 do not prevent the cytostatic actions of compounds targeting this metabolic pathway.

Abnormal expression of cell cycle regulatory proteins in ductal and lobular carcinomas of the breast

In a previous study, we demonstrated that the G1 cell cycle checkpoint in carcinomas of the breast is frequently abrogated by loss of p16, the product of the CDKN2/INK4A gene, and, to a lesser extent, by loss of pRB, the product of the retinoblastoma gene. The purpose of the present study was to determine whether other mechanisms of cell cycle deregulation exist in breast cancers which have retained RB and p16 function. Paraffin sections of 81 invasive breast carcinomas (49 ductal, 26 lobular, 6 mixed) were reacted with monoclonal antibodies against cyclin D1 and p53, using optimized immunohistochemical staining protocols. The staining results were correlated with the expression of p16 and pRB, and with a variety of pathological parameters and DNA ploidy. Twenty-five tumors (31%) accumulated (presumably mutant) p53 and 28 (35%) overexpressed cyclin D1; 7 carcinomas (not including any pure lobular cancers) abnormally expressed both proteins. p53 accumulation correlated with nuclear, mitotic, and overall grade, but not with tumor size, lymph node involvement, or DNA ploidy. Overexpression of cyclin D1 was not associated with any of the patho-biological variables. There was an inverse correlation between loss of p16 and high levels of p53, but not cyclin D1. The G1 cell cycle checkpoint, which is controlled by RB, cyclin D1, and p16, was abrogated in 65% of carcinomas, and only p53 was abnormal in an additional 17%. The number of abnormally expressed genes correlated with mitotic activity and overall tumor grade, but not with tumor histology, size, or nodal status, suggesting that cell cycle deregulation is an early event in breast tumorigenesis. Only 18% of the carcinomas showed a normal level of expression of the four genes tested, and p16 appeared to be the most common target of cell cycle deregulation. These data point to the importance of cell cycle regulatory protein abnormalities in human breast cancer.

The cell cycle and drug discovery: the promise and the hope

In recent years, there have been major developments in the understanding of the cell cycle. It is now known that normal cellular proliferation is tightly regulated by the activation and deactivation of a series of proteins that constitute the cell cycle machinery. The expression and activity of components of the cell cycle can be altered during the development of a variety of diseases where aberrant proliferation contributes to the pathology of the illness. Apart from yielding a new source of untapped therapeutic targets, it is likely that manipulating the activity of such proteins in diseased states will provide an important route for treating proliferative disorders, and the opportunity to develop a novel class of future medicines.

Potentiation of human estrogen receptor alpha transcriptional activation through phosphorylation of serines 104 and 106 by the cyclin A-CDK2 complex

Both estradiol binding and phosphorylation regulate transcriptional activation by the human estrogen receptor alpha (ER). We have previously shown that activation of the cyclin A-CDK2 complex by overexpression of cyclin A leads to enhanced ER-dependent transcriptional activation and that the cyclin A-CDK2 complex phosphorylates the ER N-terminal activation function-1 (AF-1) between residues 82 and 121. Within ER AF-1, serines 104, 106, and 118 represent potential CDK phosphorylation sites, and in this current study, we ascertain their importance in mediating cyclin A-CDK2-dependent enhancement of ER transcriptional activity. Cyclin A overexpression does not enhance transcriptional activation by an ER derivative bearing serine-to-alanine changes at residues 104, 106, and 118. Likewise, the cyclin A-CDK2 complex does not phosphorylate this triple-mutated derivative in vitro. Individual serine-to-alanine mutations at residues 104 and 106, but not 118, decrease ER-dependent transcriptional enhancement in response to cyclin A. The same relationship holds for ER phosphorylation by cyclin A-CDK2 in vitro. Finally, enhancement of ER transcriptional activation by cyclin A is evident in the absence and presence of estradiol, as well as in the presence of tamoxifen, suggesting that the effect of the cyclin A-CDK2 on ER transcriptional activation is AF-2-independent. These results indicate that the enhancement of ER transcriptional activation by the cyclin A-CDK2 complex is mediated via the AF-1 domain by phosphorylation of serines 104 and 106. We propose that these residues control ER AF-1 activity in response to signals that affect cyclin A-CDK2 function.