Early recurrence of benign meningioma correlates with expression of mini-chromosome maintenance-2 protein

MYC-targeted genes predict distant recurrence in patients with ocular adnexal extranodal marginal zone lymphoma

Ocular adnexal extranodal marginal zone lymphoma (OA-EMZL) is the most frequent subtype of ocular adnexal lymphoma, with a high propensity for recurrence. Distant recurrence (DR) as an essential prognostic event has unique clinical risk factors, but whether distinct molecular features exist remains poorly understood. Here, we identified potential biomarkers using proteomic analysis of 27 OA-EMZL samples. The MYC-targeted genes PCNA, MCM6, and MCM4 were identified as candidates. MYC-targeted genes were further identified as the most significantly activated gene set in patients with DR. The candidate genes were verified in samples from 11 patients with DR and 33 matched controls using immunohistochemistry. The 3-year and 5-year AUC values of MCM6 (0.699 and 0.757) were higher than those of Ki-67 (0.532 and 0.592). High expressions of MCM6 and MCM4 were significantly associated with shorter distant recurrence-free survival (Log-rank p = 0.017, Log-rank p = 0.0053). Multivariate Cox regression identified MCM6 expression as an independent risk factor for DR (HR, 6.86; 95% CI, 1.32-35.79; P = 0.02). Knockdown of c-Myc in B cells resulted in decreased MCM6 and MCM4 expression and reduced proliferative capacity. Our results suggest that activation of the MYC-targeted gene is a distinct molecular feature of DR in OA-EMZL. MYC-targeted gene, MCM6, is a promising pathological biomarker for DR.

Metallothionein protein and minichromosome maintenance protein-2 expression in adrenocortical tumors

AIM

Some resected adrenal-confined adrenocortical carcinomas metastasize and others not. The present study was designed to evaluate the expression of metallothionein protein (MT) and minichromosome maintenance protein-2 (MCM2) in adrenocortical carcinomas and adrenocortical adenomas, and to test the correlation between this and adrenocortical carcinoma aggressiveness.

MATERIALS AND METHODS

The study comprised 14 patients operated on for adrenocortical carcinoma, 15 operated on for adrenocortical adenoma and 2 with normal adrenals. Hematoxylin-eosin staining was used for histological evaluation under light microscopy, and sequential sections were used for MCM2 and MT staining.

RESULTS

In normal adrenals, positive staining was weak for MT and zero for MCM2. Rates of positive staining for MT and MCM2 were significantly higher in adrenocortical carcinomas than in adrenocortical adenomas (P=0.008 and P<0.001, respectively). In adrenocortical carcinomas, a significant positive correlation was found between MCM2 staining and Weiss revisited score (P=0.022) but not for Weiss score, and a significant positive correlation was found between MCM2 and mitotic rate on histology (P=0.033). MCM2 but not MT staining was also shown to correlate significantly with stage IV carcinoma (P=0.008 and P=0.165, respectively).

CONCLUSION

MCM2 and MT are overexpressed in adrenocortical carcinoma, and MCM2 expression correlates significantly with metastatic disease.

Analysis of Minichromosome Maintenance-2 (MCM-2) and Cyclin D1 Expression in Meningioma

World Health Organization histopathological grading of meningioma is associated with recurrence and clinical outcome. Grade II meningioma can be difficult to distinguish with grade I especially in case in which mitosis is not easily identified. MCM-2 and Cyclin D1 play crucial role in cell cycle and have been reported overexpressed in many malignant tumors. The aim of this observational analytic study was to analyze the differences and correlation between MCM-2 and Cyclin D1 in various meningioma grading. Immunohistochemystry with MCM-2 and Cyclin D1 was performed on 25 paraffin blocks of grade I, II and III meningiomas at the Laboratory of Anatomical Pathology, Dr. Soetomo Hospital. The immunoexpression are evaluated using Labelling Index, then analyzed statistically. The results showed significant difference in expression of MCM-2 within various meningioma grading (p=0.000) and significant difference in expression of Cyclin D1 within grade I and II also within grade I and III (p<0.050), but not in grade II and III (p>0.050). There was also positive correlation between MCM-2 and Cyclin D1 expression in various meningioma grading (rs=0.683, p=0.000). MCM-2 may play role in distinguishing various meningioma grading. Cyclin D1 can distinguish grade I and II also grade I and III, but not grade II and III. Overexpression MCM-2 was along with Cyclin D1 in various meningioma gradings.

MCM7 expression is a promising predictor of recurrence in patients surgically resected for meningiomas

Patients with high risk of recurrence after meningioma resection might benefit from adjuvant radiation therapy and closer clinical follow-up. While the World Health Organization (WHO) classification and the MIB-1 biomarker are applied in the clinical practice to identify these patients, the reliability of these methods is questionable. To improve the prediction of tumor recurrence, this study evaluated and compared the prognostic usefulness of the biomarker MCM7 with the conventional mitotic index and the MIB-1 biomarker. One hundred sixty patients were retrospectively analyzed. The expression of MIB-1 and MCM7 was determined as proliferative indices (PI-percentage of positive immunoreactive cells among 1000 tumor cells) in tissue microarrays. MCM7 PI revealed significantly higher indices in recurrent meningiomas compared with non-recurrent meningiomas (p = 0.020), while mitotic index and MIB-1 PI did not reach statistical significance (p ≥ 0.547). The optimal cutoff values for recurrence prediction were 3% for MIB-1 PI and 8% for MCM7 PI. MCM7 PI was significantly associated with recurrence-free survival in COX multivariate survival analyses (p = 0.005), while no association was found with mitotic index or MIB-1 (p ≥ 0.153). MCM7 PI allowed for the most accurate prediction of recurrence, obtaining the highest sensitivity and the greatest area under the ROC curve. These results proved that MCM7 PI is a better method for identifying patients with risk of recurrence compared with the traditional methods used in the current clinical practice. MCM7 may thus improve diagnostics, prediction of prognosis and treatment decision making in patients suffering from meningiomas.

Ki67, PCNA, and MCM proteins: Markers of proliferation in the diagnosis of breast cancer

The proliferative activity of tumour cells represents an important prognostic marker in the diagnosis of cancer. One of the methods for assessing the proliferative activity of cells is the immunohistochemical detection of cell cycle-specific antigens. For example, Ki67, proliferating cell nuclear antigen (PCNA), and minichromosome maintenance (MCM) proteins are standard markers of proliferation that are commonly used to assess the growth fraction of a cell population. The function of Ki67, the widely used marker of proliferation, still remains unclear. In contrast, PCNA and MCM proteins have been identified as important participants of DNA replication. All three proteins only manifest their expression during the cell division of normal and neoplastic cells. Since the expression of these proliferative markers was confirmed in several malignant tumours, their prognostic and predictive values have been evaluated to determine their significance in the diagnosis of cancer. This review offers insight into the discovery of the abovementioned proteins, as well as their current molecular and biological importance. In addition, the functions and properties of all three proteins and their use as markers of proliferation in the diagnosis of breast cancer are described. This work also reveals new findings about the role of Ki67 during the mitotic phase of the cell cycle. Finally, information is provided about the advantages and disadvantages of using all three antigens in the diagnosis of cancer.

Minichromosome Maintenance (MCM) Family as potential diagnostic and prognostic tumor markers for human gliomas

Background

Gliomas are the most common type of all central nervous system tumors. Almost all patients diagnosed with these tumors have a poor prognostic outcome. We aimed to identify novel glioma prognosis-associated candidate genes.

Methods

We applied WebArrayDB software to span platform integrate and analyze the microarray datasets. We focused on a subset of the significantly up-regulated genes, the minichromosome maintenance (MCM) family. We used frozen glioma samples to predict the relationship between the expression of MCMs and patients outcome by qPCR and western blot.

Results

We found that MCMs expression was significantly up-regulated in glioma samples. MCM2-7 and MCM10 expressions were associated with WHO tumor grade. High MCM2 mRNA expression appeared to be strongly associated with poor overall survival in patients with high grade glioma. Furthermore, we report that MCM7 is strongly correlated with patient outcome in patients with WHO grade II-IV tumor. MCM3 expression was found to be up-regulated in glioma and correlated with overall survival in patients with WHO grade III tumor. MCM2, MCM3 and MCM7 expression levels were of greater prognostic relevance than histological diagnosis according to the current WHO classification system.

Conclusions

High expression of MCM 2, MCM3 and MCM7 mRNA correlated with poor outcome and may be clinically useful molecular prognostic markers in glioma.

Replication proteins and human disease

In this article, we discuss the significance of DNA replication proteins in human disease. There is a broad range of mutations in genes encoding replication proteins, which result in several distinct clinical disorders that share common themes. One group of replication proteins, the MCMs, has emerged as effective biomarkers for early detection of a range of common cancers. They offer practical and theoretical advantages over other replication proteins and have been developed for widespread clinical use.

Over expression of minichromosome maintenance genes is clinically correlated to cervical carcinogenesis

Minichromosome Maintenance (MCM) proteins play important roles in cell cycle progression by mediating DNA replication initiation and elongation. Among 10 MCM homologues MCM 2–7 form a hexamer and assemble to the pre-replication complex acting as replication licensing factors. Binding and function of MCM2-7 to pre-replication complex is regulated by MCM10 mediated binding of RECQL4 with MCM2-7. The purpose of this study is to explore the role of MCMs in cervical cancer and their correlation with the clinical parameters of cervical cancer. We have investigated sixty primary cervical cancer tissue samples, eight cervical cancer cell lines and thirty hysterectomised normal cervical tissue. The expression profiling of MCMs was done using semi-quantitative RT-PCR, immunoblotting and immunohistochemistry. MCM2, 4, 5, 6, 7, 10 and RECQL4 are significantly over-expressed in cervical cancer. Among these, MCM4, 6 and 10 show increased frequency of over expression along with advancement of tumor stages. MCM4, 5 and 6 also show differential expression in different types of lesion, while MCM2 and MCM10 are over expressed in cervical cancer irrespective of clinico-pathological parameters. Our data indicates the role of MCM4, MCM5, MCM6, MCM10 and RECQL4 in the progression of cervical cancer.

Expression and clinical significance of the proliferation marker minichromosome maintenance protein 2 (Mcm2) in diffuse astrocytomas WHO grade II

Background

The WHO classification system for astrocytomas is not considered optimal, mainly because of the subjective assessment of the histopathological features. Few prognostic variables have been found that stratify the risk of clinical progression in patients with grade II astrocytoma. For that reason there is a continuous search for biomarkers that can improve the histopathological diagnosis and prognostication of these tumours.

Aim

This study was designed to investigate the prognostic significance of the proliferative marker Mcm2 (minichromosome maintenance protein 2) in diffuse astrocytomas WHO grade II and correlate the findings with histopathology, mitoses, and Ki67/MIB-1 immunostaining.

Method

61 patients with histologically verified grade II astrocytoma (WHO 2007) were investigated. Paraffin sections were immunostained with anti-Mcm2, and the Mcm2 proliferative index (PI) was determined as the percentage of immunoreactive tumour cell nuclei.

Results

Mcm2 PI was not associated with any histopathological features but correlated significantly with mitotic count and Ki67/MIB-1 PI (p<0.05). In the survival analyses Mcm2 showed trends to poorer survival, however, statistical significance was not achieved in the univariate analyses (p>0.05).

Conclusions

In our hands Mcm2 immunostaining has no advantage over Ki67/MIB-1 in the evaluation of grade II astrocytomas. Larger studies are needed to fully clarify the prognostic role of this biomarker.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1715002791944037

Expression of minichromosome maintenance MCM6 protein in meningiomas is strongly correlated with histologic grade and clinical outcome

The 2007 World Health Organization histologic grading of meningiomas is associated with recurrence and clinical outcome. However, distinction of grade I from grade II (atypical) meningiomas can be challenging. In the World Health Organization classification, there are 4 parameters on the basis of which grade II status can be determined: mitotic rate, cytoarchitectural features, brain invasion, and/or histologic subtype. Furthermore, this classification fails to detect grade I recurrent meningiomas, for which other prognostic criteria would be needed. The aim of this study was to evaluate the respective value of several markers involved in cell cycle as effective tools to predict recurrence. This retrospective study was based on a series of 59 meningiomas (grade I: 32 of 59, grade II: 27 of 59, all harboring ≥4 mitoses/1.6 mm), analyzed with the following immunohistochemical markers: MCM6, Ki-67, PHH3, cyclin D1, and p53. We found a significant correlation between histologic grade and mean labeling index for MCM6 (grade I: 21.8% vs. grade II: 65.8%; P<0.001), Ki-67 (3.2% vs. 16.9%; P<0.001), PHH3 (0.7‰ vs. 2.8‰; P<0.001), cyclin D1 (50.4% vs. 70.0%; P=0.005), and p53 (17.3% vs. 32.4%; P=0.017). Histologic grading and mitotic index were correlated with progression-free survival (P=0.010 and P=0.020, respectively). A nearly linear correlation was found between progression-free survival and staining for MCM6 (P<0.001), Ki-67 (P=0.003), and PHH3 (P=0.037) but not for cyclin D1 (P=0.400) and p53 (P=0.758). The interobserver agreement coefficients for MCM6, Ki-67, PHH3, cyclin D1, and p53 were, respectively, 0.97 (95% confidence interval, 0.95-0.98), 0.93 (0.89-0.96), 0.81 (0.70-0.88), 0.90 (0.83-0.94), and 0.84 (0.73-0.90). In conclusion, because of its strong level of expression and sharp difference in labeling index between indolent and recurrent tumors, MCM6 is the most efficient marker to identify tumors with a high risk of recurrence.

Proliferative and metabolic markers in incompletely excised pediatric pilocytic astrocytomas--an assessment of 3 new variables in predicting clinical outcome

Although pilocytic astrocytoma (PA) is the most common brain tumor diagnosed in children, few prognostic variables have been delineated that stratify the risk of clinical progression in patients with this tumor. In this study, the MIB-1 labeling index was compared with 2 other immunohistochemical markers of cell proliferation, phospho-histone H3 (PHH3) and mini-chromosomal maintenance protein 2 (MCM2) in 80 incompletely resected PAs to see which was best able to identify patients at risk for tumor progression. 0(6)-Methylguanine-DNA methyltransferase (MGMT) protein expression, which has been predictive of progression-free survival (PFS) in high-grade gliomas in children, was also evaluated in these cases. The mean follow-up period was 7.81 ± 3.9 years, and 42.8% of tumors have shown progression at the time of censoring. A MIB-1 labeling index ≥2.0 was associated with shortened PFS as a grouped variable by log-ranked analysis (P = .03) and by Cox regression analysis as a continuous variable (P = .007). None of the other potential biomarkers was significantly predictive of PFS. Although the amount of MCM2 staining correlated with the MIB-1 labeling index (P < .001), MCM2 reactivity was not independently associated with outcome. We conclude that MIB-1 labeling remains the best predictor of PFS in pediatric PAs.

Comparative protein profiling reveals minichromosome maintenance (MCM) proteins as novel potential tumor markers for meningiomas

Meningiomas are among the most frequent tumors of the brain and spinal cord accounting for 15-20% of all central nervous system tumors and frequently associated with neurofibromatosis type 2. In this study, we aimed to unravel molecular meningioma tumorigenesis and discover novel protein biomarkers for diagnostic and/or prognostic purposes and performed in-depth proteomic profiling of meningioma cells compared to human primary arachnoidal cells. We isolated proteins from meningioma cell line SF4433 and human primary arachnoidal cells and analyzed the protein profiles by Gel-nanoLC-MS/MS in conjunction with protein identification and quantification by shotgun nanoLC tandem mass spectrometry and spectral counting. Differential analysis of meningiomas revealed changes in the expression levels of 281 proteins (P < 0.01) associated with various biological functions such as DNA replication, recombination, cell cycle, and apoptosis. Among several interesting proteins, we focused on a subset of the highly significantly up-regulated proteins, the minichromosome maintenance (MCM) family. We performed subsequent validation studies by qRT-PCR in human meningioma tissue samples (WHO grade I, 14 samples; WHO grade II, 7 samples; and WHO grade III, 7 samples) compared to arachnoidal tissue controls (from fresh autopsies; 3 samples) and found that MCMs are highly and significantly up-regulated in human meningioma tumor samples compared to arachnoidal tissue controls. We found a significant increase in MCM2 (8 fold), MCM3 (5 fold), MCM4 (4 fold), MCM5 (4 fold), MCM6 (3 fold), and MCM7 (5 fold) expressions in meningiomas. This study suggests that MCM family proteins are up-regulated in meningiomas and can be used as diagnostic markers.

Regulation of minichromosome maintenance gene family by microRNA-1296 and genistein in prostate cancer

The minichromosome maintenance (MCM) gene family is essential for DNA replication and is frequently upregulated in various cancers. Here, we examined the role of MCM2 in prostate cancer and the effect of microRNA-1296 (miR-1296), genistein, and trichostatin A (TSA) on the MCM complex. Profiling results showed that expression of MCM genes was higher in tumor samples. Genistein and TSA significantly downregulated the expression of all MCM genes. Genistein, TSA, and small interfering RNA duplexes caused a significant decrease in the S phase of the cell cycle. There was also downregulation of CDT1, CDC7, and CDK2 genes, which govern loading of the MCM complex on chromatin. We also found that miR-1296 was significantly downregulated in prostate cancer samples. In PC3 cells, inhibition of miR-1296 upregulated both MCM2 mRNA and protein, whereas overexpression caused a significant decrease in MCM2 mRNA, protein, and the S phase of the cell cycle. MCM genes are excellent anticancer drug targets because they are essential DNA replication factors that are highly expressed in cancer cells. This is the first report showing anti-MCM effect by miR-1296, genistein, and TSA. TSA is undergoing clinical trials as a prostate cancer treatment but has high toxicity. Genistein, a natural, nontoxic dietary isoflavone, may be an advantageous therapeutic agent for treating prostate cancer. The use of RNA interference is currently being implemented as a gene-specific approach for molecular medicine. The specific downregulation of oncogenes by miR may contribute to novel therapeutic approaches in the treatment of prostate cancer.

Does protein expression predict recurrence of benign World Health Organization grade I meningioma?

The aim of this study was to assess the predictive value of recurrence of protein expression in surgical samples of meningiomas. Thus, the expression of proteins that have been reported to be associated with prognosis of meningiomas was assessed in a sample of 59 World Health Organization grade I tumors obtained after Simpson grade I to III surgical resection (complete excision) and that were followed for 6 to 16 years. The expression was investigated applying immunohistochemical and tissue microarray techniques. One protein, the hepatocytic growth factor receptor, of 22 investigated proteins, showed significantly differing expression when comparing the 38 nonrecurrent with the 21 recurrent World Health Organization grade I meningiomas. It is noteworthy however that by means of logistic regression analyses, the independent predictive value of this protein expression was not significantly associated with the recurrence. Furthermore, it is noteworthy that the proliferation rate estimated by means of Ki67 expression did not show a significant difference, being 3.3 +/- 0.4 for the nonrecurrent meningioma and 3.9 +/- 0.5 for the recurrent and ranging from 0% to 10%. A significant and differing Spearman rank order of correlation was noted between 19 pairs of the investigated proteins when comparing nonrecurrent with recurrent World Health Organization grade I meningiomas. None of these correlations, however, showed a significant association by means of logistic regression analyses. Our results indicate that the Simpson grade significantly alters the outcome of a World Health Organization I grade meningioma and a longer follow-up period significantly increases the risk of recurrence. The expression of none of the proteins or correlation between protein expressions previously reported to be of significance regarding recurrence can be recommended as a diagnostic tool while assessing the risk of recurrence of World Health Organization grade I meningiomas.

mRNA expression of minichromosome maintenance 2 in colonic adenoma and adenocarcinoma

As proliferation is essential for progression from normal cells to tumor, certain markers specific to proliferating cells may permit detection of premalignant lesions. Here, we aimed to evaluate the possible value of a proliferation marker, minichromosome maintenance 2 (MCM2), in the early diagnosis of colorectal cancer, by analyzing the difference in MCM2 expression among normal mucosa, adenoma, and adenocarcinoma, and investigating the relationship of MCM2 expression in adenomas with clinicopathologic variables. Using immunohistochemistry and real-time reverse transcription-PCR, we observed that the expression of MCM2 protein was present on basal third to half of colonic crypts in normal mucosa, whereas throughout the epithelium in adenomas and adenocarcinomas, the expression of MCM2 mRNA in adenocarcinomas was significantly higher than in adenomas (P=0.001), whereas the difference between adenoma and normal mucosa was not significant (P=0.184); we also found that the expression of MCM2 mRNA tended to be increased in the adenomas with high-grade dysplasia, or in older patients, respectively, compared with those with low-grade dysplasia, and younger patients. These results suggested the potential value of MCM2 in early diagnosis of colorectal cancer.

Minichromosome maintenance protein 2 is a reliable proliferative marker in breast carcinoma

This is a study aimed to examine the distribution pattern of a specific minichromosome maintenance protein 2 (MCM2) in benign and malignant breast tissue. We also aim to correlate the frequency of expression of MCM2 with the degree of tumor differentiation. We used immunohistochemistry to examine the distribution and expression pattern of MCM2 on formalin-fixed paraffin-embedded tissue sections of benign (n = 30) and malignant breast tissue (n = 70) (IDC 56, DCIS 4, ILC 2, nonductal 4, mixed type 4). We quantified MCM2 expression by calculating a labeling index, which represents the percentage of epithelial nuclei that stained positively. Immunoreactivity was heterogenous in all the 70 malignant cases examined. Epithelial cells in cycle are most frequent at the tumor periphery. Labeling index of MCM2 was greatest in grade 3 (poorly differentiated) and lowest in grade 1 tumors (well differentiated). Minichromosome maintenance protein 2 expression in breast cancer showed a positive association with histologic grade (P < .05). In all the benign breast tissue examined, no proliferating compartments could be characterized. Minichromosome maintenance protein 2 is a useful proliferative marker of breast carcinoma. The frequency of expression of MCM2 showed an inverse correlation with the degree of tumor differentiation.

Minichromosome maintenance 2 (MCM2) immunoreactivity in stage III human gastric carcinoma: clinicopathological significance

BACKGROUND

The origin licensing factor minichromosome maintenance 2 (MCM2) has recently been identified as a critical regulator of proliferation in both normal and neoplastic cells. This study examined whether MCM2 expression was of prognostic relevance in patients with stage III gastric carcinoma and whether the expression of this marker showed any correlation with clinicopathological characteristics. In addition, we evaluated whether the expression of this proliferation marker was correlated with that of another marker, Ki-67, in gastric carcinoma.

METHODS

We examined the immunohistochemical expression of MCM2, Ki-67, and p53 in 103 surgically removed stage III gastric carcinomas, which consisted of 60 intestinal-type and 43 diffuse-type carcinomas. The labeling indices (LIs) of MCM2 and Ki-67 in cancer cells were compared with clinicopathological characteristics, p53 expression, and overall survival rates.

RESULTS

The mean MCM2 and Ki-67 LIs were 69.1 +/- 11.8% and 48.2 +/- 14.5%, respectively, in the intestinal carcinomas, and 43.7 +/- 9.9% and 24.9 +/- 11.0%, respectively, in the diffuse carcinomas. The LIs of these proteins revealed no significant association with clinicopathological characteristics or with p53 expression in the carcinomas. Kaplan-Meier survival curves showed that, in the patients with diffuse carcinoma, those with higher MCM2 LIs had a poorer prognosis (P < 0.05), but the MCM2 LI was not correlated with prognosis for those with intestinal carcinoma (P = 0.25). Ki-67 expression had no significant correlation with prognosis in either intestinal-type or diffuse-type carcinomas. Multivariate Cox regression analysis confirmed that MCM2 was an independent prognostic factor in patients with diffuse carcinoma.

CONCLUSION

Our data suggest that MCM2 is a useful prognostic marker in patients stage III diffuse-type gastric carcinoma.

Meningioma

Meningiomas are mostly benign tumours originating from the arachnoid cap cells, represent 13-26% of all intracranial tumours. They are more common in older age and in females. Deletion in NF2 gene and exposure to ionizing radiation are established risk factors, while the role of sex hormones is yet not clarified. Five-year survival for typical meningiomas exceeds 80%, but is poorer (5-year survival <60%) in malignant and atypical meningiomas. Papillary and haemangiopericytic morphology, large tumour size, high mitotic index, absence of progesterone receptors, deletions and loss of heterozygosity are poor prognostic factors. Complete surgical excision is the standard treatment. Radiotherapy is currently used in the clinical practice in atypical, malignant or recurrent meningioma at a total dose of 45-60Gy. However, the role of adjuvant irradiation is still controversial and has to be compared in a randomised prospective setting with a policy of watchful waiting. Radiosurgery has gained more and more importance in the management of meningiomas, especially in meningiomas that cannot be completely resected as for many skull base meningiomas. Medical therapy for patients with recurrent, progressive and symptomatic disease after repeated surgery, radiosurgery and radiotherapy is investigational. Hormonal therapy with progesterone antagonists has shown modest results, while chemotherapy with hydroxyurea appears moderately active.

Minichromosome maintenance proteins 2 and 5 in non-benign epithelial ovarian tumours: relationship with cell cycle regulators and prognostic implications

Minichromosome maintenance proteins (MCM) have recently emerged as novel proliferation markers with prognostic implications in several tumour types. This is the first study investigating MCM-2 and MCM-5 immunohistochemical expression in a series of ovarian adenocarcinomas and low malignant potential (LMP) tumours aiming to determine possible associations with clinicopathological parameters, the conventional proliferation index Ki-67, cell cycle regulators (p53, p27(Kip1), p21(WAF1) and pRb) and patients' outcome. Immunohistochemistry was applied in a series of 43 cases of ovarian LMP tumours and 85 cases of adenocarcinomas. Survival analysis was restricted to adenocarcinomas. The median MCM-2 and MCM-5 labelling indices (LIs) were significantly higher in adenocarcinomas compared to LMP tumours (P<0.0001 for both associations). In adenocarcinomas, the levels of MCM-2 and MCM-5 increased significantly with advancing tumour stage (P=0.0052 and P=0.0180, respectively), whereas both MCM-2 and MCM-5 increased significantly with increasing tumour grade (P=0.0002 and P=0.0006, respectively) and the presence of bulky residual disease (P<0.0001 in both relationships). A strong positive correlation was established between MCM-2 or MCM-5 expression level and Ki-67 LI (P<0.0001) as well as p53 protein (P=0.0038 and P=0.0500, respectively). Moreover, MCM-2 LI was inversely correlated with p27(Kip-1) LI (P=0.0068). Finally, both MCM-2 and MCM-5 were associated significantly with adverse patients' outcome in both univariate (> or =20 vs >20%, P=0.0011 and > or =25 vs <25%, P=0.0100, respectively) and multivariate (P=0.0001 and 0.0090, respectively) analysis. An adequately powered independent group of 45 patients was used in order to validate our results in univariate survival analysis. In this group, MCM-2 and MCM-5 expression retained their prognostic significance (P<0.0001 in both relationships). In conclusion, MCM-2 and MCM-5 proteins appear to be promising as prognostic markers in patients with ovarian adenocarcinomas.

Recurrences of meningiomas: predictive value of pathological features and hormonal and growth factors

OBJECTIVE

Recurrence of apparently completely resected benign meningiomas is a rather frequent event, the mechanisms of which are still unclear. The aim of this study is to define the pathological features, proliferation indexes, growth factors and hormone receptor expression in predicting the meningioma recurrence.

METHODS

Two groups of 50 completely resected benign WHO I meningiomas, with and without recurrence respectively, have been reviewed. Tumor location, consistency, vascularity, and histological types have been considered. Immunohistological studies include mitotic index (MI), Ki-67 LI, estrogen and progesterone receptors (ER and PR), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), and Bcl-2. All these factors have been correlated with the recurrence.

RESULTS

The tumor recurrence was not correlated with the patient age, tumor location, consistency, vascularity and histology. There was not difference in the histological pattern between local and diffuse recurrences. M.I. and Ki-67 LI were significantly correlated with the recurrence (P<0.0001). PR negativity had a strong predictive value of recurrence (P<0.0001), whereas the ER status was not relevant. VEGF and EGF-R were not correlated with the recurrence of meningiomas, whereas the Bcl-2 protein positivity showed a tendency to the significativity (P=0.0294). The negative association between Bcl-2 and PR is an interesting finding of our study.

CONCLUSIONS

Higher MI and Ki-67 LI and PR negativity are predictive factors of recurrence of benign (WHO I) completely resected meningiomas, particularly when Bcl-2 positivity is associated.

The medulloblastoma cell line DAOY but not eleven other tumor cell lines expresses minichromosome maintenance protein 4

Minichromosome maintenance proteins (MCM) are required for initiation and elongation of chromosomal DNA, ensuring that DNA replication takes place only once. Although MCMs are considered of utmost importance in tumor biology and as potential marker proteins, they were not unambiguously identified at the protein level and we therefore aimed to characterize MCM 4 in a medulloblastoma cell line and provide a protein chemical analytical tool. In addition, we searched for this protein in twelve tumor cell lines and a series of non-tumor cells. The DAOY medulloblastoma cell line was cultivated, lysed, proteins extracted and run on two-dimensional gel electrophoresis with subsequent in-gel digestion and mass spectrometrical (MS/MS) analysis of protein spots. One spot at pI 6.2 with an observed molecular weight of 98 kDa was identified as minichromosome maintenance protein 4 by peptide fingerprinting. Sequence coverage of 35% along with 25 matched peptides and MS/MS analyses of three matching peptides warranted unambiguous identification. The use of mass spectrometrical identification unequivocally allowed determination of MCM 4 expression in a medulloblastoma cell line exclusively. Given the biological and probable clinical importance of this molecule as a tentative marker protein, a fair analytical tool, independent of antibody availability and specificity is mandatory and determinations at the transcriptional level cannot be extrapolated to protein levels per se, as there is a long and unpredictable way from mRNA to protein.

Expression of minichromosome maintenance protein 2 as a marker for proliferation and prognosis in diffuse large B-cell lymphoma: a tissue microarray and clinico-pathological analysis

Background

Minichromosome maintenance (MCM) proteins are essential for the initiation of DNA replication and have been found to be relevant markers for prognosis in a variety of tumours. The aim of this study was to assess the proliferative activity of diffuse large B-cell lymphoma (DLBCL) in tissue microarray (TMA) using one of the minichromosome maintenance proteins (Mcm2) and to explore its potential value to predict prognosis.

Methods

Immunohistochemistry for Mcm2 was performed on TMAs constructed from 302 cases of DLBCL. A monoclonal mouse antibody was used after heat induced antigen retrieval. Mcm2 expression was scored quantitatively. Positivity for Mcm2 was defined as presence of nuclear expression of Mcm2 in greater than or equal to 40 % of tumour cells. A statistical analysis was carried out of the association of Mcm2 and the clinico-pathological characteristics.

Results

Mcm2 expression was clearly evident in the nuclei of proliferating non-neoplastic cells and tumour cells. Positivity for Mcm2 was found in 46% (98/211) of analysable cases. A significant correlation existed between Mcm2 expression and presence of bulky disease (p = 0.003). Poor disease specific survival was observed in patients with DLBCL positive for Mcm2 expression in the univariate analysis (p = 0.0424).

Conclusion

Mcm2 expression can be used to assess tumour proliferation and may be useful as an additional prognostic marker to refine the prediction of outcome in DLBCL.

Immunohistochemical estimation of cell cycle entry and phase distribution in astrocytomas: applications in diagnostic neuropathology

An immunohistochemical method for assessing cell cycle phase distribution in neurosurgical biopsies would enable such data to be incorporated into diagnostic algorithms for the estimation of prognosis and response to adjuvant chemotherapy in glial neoplasms, without the requirement for flow cytometric analysis. Paraffin-embedded sections of intracerebral gliomas (n = 48), consisting of diffuse astrocytoma (n = 9), anaplastic astrocytoma (n = 8) and glioblastoma (n = 31), were analysed by immunohistochemistry using markers of cell cycle entry, Mcm-2 and Ki67, and putative markers of cell cycle phase, cyclins D1 (G1-phase), cyclin A (S-phase), cyclin B1 (G2-phase) and phosphohistone H3 (Mitosis). Double labelling confocal microscopy confirmed that the phase markers were infrequently coexpressed. Cell cycle estimations by immunohistochemistry were corroborated by flow cytometric analysis. There was a significant increase in Mcm-2 (P < 0.0001), Ki67 (P < 0.0001), cyclin A (P < 0.0001) and cyclin B1 (P = 0.002) expression with increasing grade from diffuse astrocytoma through anaplastic astrocytoma to glioblastoma, suggesting that any of these four markers has potential as a marker of tumour grade. In a subset of glioblastomas (n = 16) for which accurate clinical follow-up data were available, there was a suggestion that the cyclin A:Mcm-2 labelling fraction might predict a relatively favourable response to radical radiotherapy. These provisional findings, however, require confirmation by a larger study. We conclude that it is feasible to obtain detailed cell cycle data by immunohistochemical analysis of tissue biopsies. Such information may facilitate tumour grading and may enable information of prognostic value to be obtained in the routine diagnostic laboratory.

Cell cycle phase abnormalities do not account for disordered proliferation in Barrett's carcinogenesis

Barrett's esophagus (BE) epithelium is the precursor lesion for esophageal adenocarcinoma. Cell cycle proteins have been advocated as biomarkers to predict the malignant potential in BE. However, whether disruption of the cell cycle plays a causal role in Barrett's carcinogenesis is not clear. Specimens from the Barrett's dysplasia-carcinoma sequence were immunostained for cell cycle phase markers (cyclin D1 for G1; cyclin A for S, G2, and M; cytoplasmic cyclin B1 for G2; and phosphorylated histone 3 for M phase) and expressed as a proportion of proliferating cells. Flow cytometric analysis of the cell cycle phase of prospective biopsies was also performed. The proliferation status of nondysplastic BE was similar to gastric antrum and D2, but the proliferative compartment extended to the luminal surface. In dysplastic samples, the number of proliferating cells correlated with the degree of dysplasia (P <.001). The overall levels of cyclins A and B1 correlated with the degree of dysplasia (P <.001). However, the cell cycle phase distribution measured with both immunostaining and flow cytometry was conserved during all stages of BE, dysplasia, and cancer. Hence, the increased proliferation seen in Barrett's carcinogenesis is due to abnormal cell cycle entry or exit, rather than a primary abnormality within the cell cycle.

Control of DNA replication and its potential clinical exploitation

Multiple conserved mechanisms limit DNA replication to once per cell cycle. One vital level of control focuses on the loading of the heterohexameric ring of minichromosome maintenance proteins (MCMs) onto chromatin in the hierarchical assembly of the pre-replication complex at origins of replication. An essential role in proliferation for MCMs and their regulators makes them potentially important biomarkers for routine clinical use in cancer detection and prognosis.

Minichromosome Maintenance Protein 3 Elicits a Cancer-Restricted Immune Response in Patients with Brain Malignancies and Is a Strong Independent Predictor of Survival in Patients with Anaplastic Astrocytoma

Purpose: The identification of new molecular markers in astrocytic tumors may help to understand the biology of these tumors in more detail. Informative tumor markers may represent prognostic factors for response to therapy and outcome as well as potential targets for novel anticancer therapies.

Experimental Design: Tumor-associated antigens were identified by immunoscreening of a human glioma cDNA expression library with allogeneic sera from patients with diffuse astrocytoma (WHO grades 2-4). The expression of one of the identified antigens, the replication licensing factor minichromosome maintenance protein 3 (MCM3), was analyzed by immunohistochemistry in 142 primary and 27 recurrent astrocytomas (WHO grades 2-4). In addition, 98 serum specimens from patients with primary and secondary brain malignancies and 30 serum specimens from healthy controls were examined by serologic immunoscreening for immunoreactivity with MCM3.

Results: MCM3 is overexpressed in human astrocytic tumors and elicits a cancer-restricted humoral immune response in 9.3% (9 of 97) of patients with brain tumors (n = 95) and brain metastases (n = 2) but not in healthy controls. Expression of MCM3 in diffuse astrocytoma is significantly associated with age (P &lt; 0.001), histologic grade (P &lt; 0.001), time to recurrence (P = 0.01), and expression of the proliferation marker Ki-67 (P &lt; 0.001) but not with sex (P = 0.800). Univariate and multivariate Cox regression analysis confirmed MCM3 expression as an independent predictor of poor outcome in astrocytoma patients (P &lt; 0.001 for both).

Conclusions: MCM3 may represent a glioma-associated antigen with significant prognostic role as well as have some potential as a target for cancer-directed therapy.

Cell-cycle-dependent regulation of DNA replication and its relevance to cancer pathology

The highly orchestrated process of DNA replication ensures the accurate inheritance of genetic information from one cell generation to the next. The exact execution of DNA replication depends on a large number of proteins that are being studied extensively in the cell cycle field. Some of these proteins, such as the minichromosome maintenance proteins (MCMs), are essential for the process of DNA replication itself. Others such as geminin are specifically required to limit DNA replication to once per cell cycle. Together, these proteins protect the stability of the human genome in cycling cells. Their expression has been compared with routinely used proliferation markers, such as Ki-67 (MIB-1) and proliferating cell nuclear antigen (PCNA), which fulfil the requirements of molecular tumour markers to varying extents. However, it is with regard to the depth of our understanding of antigen biology that the MCM proteins and geminin qualify exceptionally well as novel cell-cycle biomarkers for routine use in clinical practice, particularly in cancer detection and estimation of prognosis. Expression microarray analysis has also independently identified MCMs and their interacting proteins as determinants of the inherent aggressiveness of a wide range of epithelial malignancies.

ORC-associated replication factors as biomarkers for cancer

Early detection and treatment of cancer are of central importance to improving patient prognoses. Traditional biomarkers of cell proliferation, such as Ki-67 and PCNA, have had a mixed clinical track record, proving to be good indicators of certain types of cancers but of limited use for many others. Recently, human counterparts of replication factors originally identified in budding yeast have shown great promise as new cancer biomarkers. Each of these factors has been shown to interact with the origin recognition complex (ORC) in yeast, and each has an essential role in the initiation of DNA replication. Studies with minichromosome maintenance (MCM) family proteins show that their levels are upregulated in tumor cells and are much better indicators of a wide variety of cancers than traditional biomarkers. Similarly encouraging results have been obtained in preliminary studies examining Cdc6 protein and Cdc7 kinase transcript levels in normal and cancerous cells.

A novel immunohistochemical method for estimating cell cycle phase distribution in ovarian serous neoplasms: implications for the histopathological assessment of paraffin-embedded specimens

We have investigated whether immunohistochemical markers can identify differences in cell cycle phase distribution in ovarian serous neoplasms, including borderline tumours of different grades. Sections of normal ovary (n=18), serous cystadenoma (n=21), borderline serous tumours (n=21) and serous cystadenocarcinoma (n=15) were analysed by immunohistochemistry using markers of cell cycle entry (Mcm-2) and cell cycle phase, including cyclin D1 (mid-to-late G1), cyclin A (S phase), cyclin B1 (G2 phase) and phosphohistone H3 (mitosis). Double-labelling confocal microscopy confirmed marker phase specificity and phase estimations were corroborated by flow cytometry. On progression from normal ovary through serous cystadenoma and borderline tumours to cystadenocarcinomas, expression of Mcm-2 (P<0.0001), cyclin D1 (P=0.002), cyclin A (P<0.0001), cyclin B1 (P<0.0001) and phosphohistone H3 (P<0.0001) increased, paralleled by an increase in the S-phase fraction (cyclin A : Mcm-2 ratio; P=0.002). Borderline tumours of increasing grade also showed increased Mcm-2 and cyclin A expression, together with an increase in the S-phase fraction. Immunohistochemistry can be used to estimate cell cycle phase distribution in ovarian serous neoplasms, giving results similar to flow cytometric analysis and enabling direct assessment of tumour heterogeneity. Immunohistochemical estimates of the S-phase fraction may identify serous borderline tumours likely to exhibit malignant progression and/or select serous cystadenocarcinomas likely to respond to adjuvant therapy.

Increased expression of minichromosome maintenance protein 2 in active inflammatory bowel disease

OBJECTIVE

Minichromosome maintenance protein 2 (Mcm2) is an accurate indicator of cell cycle entry in tissue samples, but its expression in inflammatory bowel disease (IBD) has not previously been investigated. We have used immunohistochemistry to assess the expression of Mcm2, in comparison to the existing proliferation marker Ki-67, in active IBD and IBD without inflammatory activity.

MATERIALS AND METHODS

For this experimental study, sections from colonic biopsy and resection specimens of 48 patients with IBD (5 inactive/quiescent Crohn's disease (CD), 13 active CD, 19 inactive/quiescent ulcerative colitis (UC) and 11 active UC) and 15 normal controls were immunostained with antibodies to Mcm2 and Ki-67. The percentage of immunopositive epithelial nuclei was determined by calculating a labelling index (LI) for entire glands and for gland thirds (superficial, middle and basal).

RESULTS

The Mcm2 LI was significantly increased in the superficial third of glands in active vs. inactive/quiescent UC (P < 0.0001) and active vs. inactive/quiescent CD (P = 0.001). The Mcm2 LI was significantly greater than the Ki-67 LI in active IBD, both in entire glands (P < 0.0001) and in the superficial third of glands (UC, P = 0.001; CD, P = 0.0002). Mcm2 LIs for entire glands were significantly higher in UC (all cases) compared to CD (all cases) (P = 0.032).

CONCLUSIONS

There is increased cell cycle entry, as indicated by expression of Mcm2 and to a lesser extent Ki-67, in the superficial third of colonic glands in active IBD compared to inactive/quiescent IBD. Detection of Mcm2 may contribute to improved histological assessment of small tissue biopsies and may enable the development of a direct stool-based test for detection of active IBD and potentially for assessment of disease activity.

Eukaryotic MCM proteins: beyond replication initiation

The minichromosome maintenance (or MCM) protein family is composed of six related proteins that are conserved in all eukaryotes. They were first identified by genetic screens in yeast and subsequently analyzed in other experimental systems using molecular and biochemical methods. Early data led to the identification of MCMs as central players in the initiation of DNA replication. More recent studies have shown that MCM proteins also function in replication elongation, probably as a DNA helicase. This is consistent with structural analysis showing that the proteins interact together in a heterohexameric ring. However, MCMs are strikingly abundant and far exceed the stoichiometry of replication origins; they are widely distributed on unreplicated chromatin. Analysis of mcm mutant phenotypes and interactions with other factors have now implicated the MCM proteins in other chromosome transactions including damage response, transcription, and chromatin structure. These experiments indicate that the MCMs are central players in many aspects of genome stability.

Minichromosome maintenance protein 2 is a strong independent prognostic marker in breast cancer

PURPOSE

To test the hypothesis that prognostic information in breast cancer may be derived from an accurate assessment of epithelial cell cycle entry, as indicated by expression of minichromosome maintenance (MCM) proteins.

MATERIALS AND METHODS

We used immunohistochemistry to examine the distribution of Mcm-2 in breast tissue. Power calculations based on a pilot study of 67 whole tissue sections led to selection of an independent 347-core breast carcinoma tissue microarray validation set. We tested for associations between Mcm-2 (and Ki-67) labeling index (LI) and various clinicopathologic parameters.

RESULTS

Mcm-2 was expressed more frequently than the standard proliferation marker Ki-67 in whole tissue sections of normal breast (P =.0003) and breast carcinoma (P <.0001). In 221 assessable cores of invasive carcinoma, the Mcm-2 LI showed a positive association with tumor size (P =.002), mitotic index (P <.0001), histologic grade (P <.0001), and the Nottingham Prognostic Index (NPI) score (P <.0001). Using a cutoff value of 50%, Mcm-2 LI was associated with overall survival (P =.0007), disease-free interval (P =.0002), and with the development of regional recurrence (P =.011) and distant metastases (P =.0016). Cox regression analysis suggested that the Mcm-2 LI is a strong prognostic factor in breast cancer that is independent and superior to histologic grade, lymph node stage, and Ki-67 LI, but not the NPI score.

CONCLUSION

Mcm-2 may be of utility as a prognostic marker to refine the prediction of outcome in breast cancer, for example when combined with parameters currently used in the NPI.

A novel immunohistochemical method to estimate cell-cycle phase distribution in archival tissue: implications for the prediction of outcome in colorectal cancer

An immunohistochemical method for assessing cell-cycle phase distribution in colorectal resection specimens would enable phase data to be incorporated into diagnostic algorithms for the estimation of prognosis and response to adjuvant chemotherapy in colorectal cancer. In contrast to flow cytometry, an immunohistochemical method would also allow the phase distribution to be examined within morphologically heterogeneous regions of neoplasms. Paraffin sections of normal colon (n = 25), colonic adenoma (n = 15), and colonic adenocarcinoma (n = 30) were analysed by immunohistochemistry using antibodies against markers of cell-cycle entry, Mcm-2 and Ki67, and putative markers of the cell-cycle phase, cyclins D1 and E (putative markers of G1 phase), cyclin A (S phase), cytoplasmic cyclin B1 (G2 phase), and phosphohistone H3 (M phase). The phase specificity of each marker was assessed by examining the degree of co-expression of adjacent phase markers using double-antibody fluorescence confocal microscopy and by comparison with flow cytometric analysis performed on adjacent tissue sections. The S-phase specificity of detectable cyclin A was also assessed in combination with in situ DNA replication using fluorescence confocal microscopy. All cells expressing phase markers co-expressed Mcm-2. Adjacent phase markers were not significantly co-expressed, confirming the relative specificity of these markers in tissue sections of colon. Cell-cycle phase distribution, calculated by immunohistochemistry, compared well with phase analyses obtained by flow cytometry. No cells expressed cyclin A in the absence of active DNA replication. The S-phase labelling index, as defined by detectable cyclin A expression, showed a positive correlation with the Mcm-2 labelling index and increased in the progression from normal colon to adenocarcinoma. In conclusion, a combination of these cell-cycle phase markers can be used to calculate the distribution of cells throughout each phase of the cell cycle in colorectal tissue sections. Detectable cyclin A can be used as a surrogate marker of S phase and may be of value in predicting prognosis and response to adjuvant therapy.

Aberrant expression of minichromosome maintenance protein-2 and Ki67 in laryngeal squamous epithelial lesions

Histological classification of laryngeal epithelial lesions is highly subjective, and methods of cytological detection are not well developed. Improved determination of aberrant cell cycle entry may allow increased objectivity in histological assessment and enable the development of less invasive diagnostic cytology tests. Sections of normal larynx (n=10), laryngeal dysplasia (n=20) and laryngeal squamous cell carcinoma (SCC) (n=10) were classified according to the Ljubljana classification and stained for markers of cell cycle entry, minichromosome maintenance protein-2 (Mcm-2) and Ki67. Expression patterns were compared using double labelling confocal microscopy. There was a correlation between Mcm-2 and Ki67 labelling indices (rho=0.93; 95% CI [0.84, 0.97]) and both markers showed increased expression from normal epithelium to SCC (Mcm-2, P=0.001; Ki67, P=0.0002). Importantly, there was minimal expression of Mcm-2 or Ki67 in the most superficial layers of normal larynx and abnormal or atypical hyperplasia, in contrast to carcinoma in situ and SCC. Clusters of Mcm-2/5-positive cells were present in cytological preparations from SCC, but not from those showing atypical hyperplasia or inflammation in non-neoplastic tissue. Minichromosome maintenance protein-2 staining may increase the objectivity and reliability of histological grading of laryngeal epithelial lesions. Laryngeal brushings, combined with immuno-enhanced liquid-based cytology, could be useful, as a less invasive approach, to the detection of laryngeal malignant and premalignant lesions.