Minichromosome Maintenance Protein 2 Expression Research Articles

Abstract P6-14-13: Association of baseline tumor-infiltrating lymphocytes and cell-cycle regulation markers on prognosis and mortality in patients with advanced breast cancer according to tumor characteristics and treatment type

Abstract We aimed to analyze the expression of cell-cycle regulation markers – minichromosome maintenance protein 2 (MCM2), Ki-67, Cyclin-A and phosphohistone-H3 (PHH3) and tumor-infiltrating lymphocytes (TILs) in pre-treatment core-biopsy samples of advanced breast carcinomas (ABC) in correlation with known predictive and prognostic factors. Consecutive breast cancer patients (n=398) treated during 2015-2019 were retrospectively analyzed. ABC was defined either as the first indication for locally recurrent, locally advanced or metastatic disease. TIL levels were evaluated of invasive tumor samples, and high expression was defined as TILs >15%. Immunohistochemistry was performed to analyze the expression of MCM2, Ki-67, Cyclin A and PHH3, which were correlated with the following clinicopathological parameters: clinical TNM, tumor grade, biological subtype, TILs, treatment type (chemotherapy-containing or non-chemotherapy). Univariate and multivariate analyses were used to assess factors associated with disease-free survival (DFS) and overall survival (OS). The multivariate analysis showed that patients with higher TIL levels had an improved 3-year DFS compared with those with low TIL levels, (79.5% vs. 63.7%, HR = 0.52, 95% CI = 0.32–0.78, p = 0.005), which may imply using the biomarkers to indicate initial treatment selection at the advanced stage. The effect was the most pronounced for triple-negative breast cancer (TNBC), and higher for HER2+ than hormone receptor positive breast cancer (HR+). Hormone receptor negative tumors showed significantly higher expression of the studied cell-cycle regulation markers Ki-67, MCM2 and Cyclin A compared with HR+ breast cancer, with TNBC showing the highest activity. Ki-67 and MCM2 were significantly associated with worse prognosis in HR+ breast cancer (p = 0.03; p = 0.04). Treatment type (chemotherapy vs. non-chemotherapy) as the initial treatment at the advanced stage influenced the 3-year DFS and OS in patients with high TIL levels in all molecular breast cancer subtypes. For those with low levels of TILs the difference was statistically non-significant. Our study showed that TIL and cell cycle marker testing could help to identify patients with more aggressive tumor types and the requirement of more aggressive treatment upfront. The proposed biomarker testing can help in selecting the appropriate treatment for increased disease-free survival. Citation Format: Sauli Vuoti, Minna Saari, Kumar Narasimha, Kai Reinikainen. Association of baseline tumor-infiltrating lymphocytes and cell-cycle regulation markers on prognosis and mortality in patients with advanced breast cancer according to tumor characteristics and treatment type [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-14-13.

Expression of MCM2 as a Proliferative Marker in Actinic Keratosis and Cutaneous Squamous Cell Carcinoma.

Minichromosome maintenance protein 2 (MCM2) can be considered an indicator of cancer clinical outcome. In this study, we tried to estimate the usefulness of assessing MCM2 protein expression in actinic keratosis (AK) and cutaneous squamous cell carcinoma (cSCC). The study included 22 lesions of AK, 57 of cSCC and 17 tissue samples of the healthy skin. Higher average expression of MCM2 protein in cSCC and AK was demonstrated in comparison to healthy skin (p=0.01). Likewise, the level of MCM2 expression differed statistically significantly (p=0.02) between SCC, AK, and healthy skin. Significant correlations between MCM2 expression and Ki-67 and p53 antigen were found (r=0.51, p=0.01; r=0.45, p=0.04 respectively) in AK lesions, however these relationships were not noted in cSCC. MCM2 is overexpressed in both AK and cSCC lesions, however this protein cannot be considered an important indicator of proliferation in cSCC.

Thiabendazole Inhibits Glioblastoma Cell Proliferation and Invasion Targeting Mini-chromosome Maintenance Protein 2

Thiabendazole (TBZ), approved by the US Food and Drug Administration (FDA) for human oral use, elicits a potential anticancer activity on cancer cells in vitro and in animal models. Here, we evaluated the efficacy of TBZ in the treatment of human glioblastoma multiforme (GBM). TBZ reduced the viability of GBM cells (P3, U251, LN229, A172, and U118MG) relative to controls in a dose- and time-dependent manner. However, normal human astrocytes (NHA) exhibited a greater IC50 than tumor cell lines and were thus more resistant to its cytotoxic effects. 5-Ethynyl-2'-deoxyuridine (EdU)-positive cells and the number of colonies formed were decreased in TBZ-treated cells (at 150 μM, P < 0.05 and at 150 μM, P < 0.001, respectively). This decrease in proliferation was associated with a G2/M arrest as assessed with flow cytometry, and the downregulation of G2/M check point proteins. In addition, TBZ suppressed GBM cell invasion. Analysis of RNA sequencing data comparing TBZ-treated cells with controls yielded a group of differentially expressed genes, the functions of which were associated with the cell cycle and DNA replication. The most significantly downregulated gene in TBZ-treated cells was mini-chromosome maintenance protein 2 (MCM2). SiRNA knockdown of MCM2 inhibited proliferation, causing a G2/M arrest in GBM cell lines and suppressed invasion. Taken together, our results demonstrated that TBZ inhibited proliferation and invasion in GBM cells through targeting of MCM2. SIGNIFICANCE STATEMENT: TBZ inhibits the proliferation and invasion of glioblastoma cells by downregulating the expression of MCM2. These results support the repurposing of TBZ as a possible therapeutic drug in the treatment of GBM.

Computational assessment of MCM2 transcriptional expression and identification of the prognostic biomarker for human breast cancer

Minichromosome maintenance protein 2 (MCM2) is a highly conserved protein from the MCM protein family that plays an important role in eukaryotic DNA replication as well as in cell cycle progression. In addition, it maintains the ploidy level consistency in eukaryotic cells, hence, mutations or alteration of this protein could result in the disintegration of the fine-tuned molecular machinery that can lead to uncontrolled cell proliferation. Moreover, MCM2 has been found to be an important marker for progression and prognosis in different cancers. Therefore, we aimed to analyze the MCM2 expression and the associated outcome in breast cancer (BC) patients based on the publicly available online databases. In this study, server-based gene expression analyses indicate the upregulation of MCM2 (p < 10−6; fold change>2.0) in various BC subtypes as compared to the respective normal tissues. Besides, the evaluation of histological sections from healthy and cancer tissues showed strong staining signals indicating higher expression of MCM2 protein. The overexpression of MCM2 was significantly correlated to promoter methylation and was related to patients' clinical features. Further, mutation analysis suggested missense as the predominant type of mutation (71.4%) with 18 copy-number alterations and 0.2% mutation frequency in the MCM2 gene. This study revealed a significant correlation (Cox p ≤ 0.05) between the higher MCM2 expression and lower patient survival. Finally, we identified the co-expressed genes with gene ontological features and signaling pathways associated in BC development. We believe that this study will provide a basis for MCM2 to be a significant biomarker for human BC prognosis.

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

AimSome 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 methodsThe 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. ResultsIn 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). ConclusionMCM2 and MT are overexpressed in adrenocortical carcinoma, and MCM2 expression correlates significantly with metastatic disease.

Prognostic and Clinicopathological Correlations of Cell Cycle Marker Expressions before and after the Primary Systemic Therapy of Breast Cancer

We aimed to analyze the expression of cell-cycle regulation markers – minichromosome maintenance protein 2 (MCM2), Ki-67, Cyclin-A and phosphohistone-H3 (PHH3) − in pre-treatment core-biopsy samples of breast carcinomas in correlation with known predictive and prognostic factors. Totally 52 core biopsy samples obtained prior to neoadjuvant therapy were analyzed. Immunohistochemistry was performed to analyze the expression of MCM2, Ki-67, Cyclin A and PHH3, which were correlated with the following clinicopathological parameters: clinical TNM, tumor grade, biological subtype, the presence of tumor infiltrating lymphocytes (TIL), pathological tumor response rate to the neoadjuvant therapy and patient survival. All investigated markers showed higher expression in high grade and in triple negative tumors (p < 0.01 and p < 0.05, respectively). Hormone receptor negative tumors showed significantly higher expression of Ki-67 (p < 0.01), MCM2 (p < 0.01) and Cyclin A (p < 0.01) than hormone receptor positive ones. Tumors with increased TIL showed significantly higher Ki-67 expression (p = 0.04). Pattern analysis suggested that novel cell-cycle marker-based subgrouping reveals predictive and prognostic potential. Tumors with high MCM2, Cyclin A or PHH3 expression showed significantly higher rate of pathological complete remission. Tumors with early relapse (progression-free survival ≤2 years) and shortened overall survival also show a higher rate of proliferation. Our cell cycle marker (Ki-67, MCM2, Cyclin A, PHH3) based testing could identify tumors with worse prognosis, but with a favorable response to primary systemic therapy. The pattern of cell-cycle activity could also be useful for predicting early relapse, but our findings need to be further substantiated in larger patient cohorts.

Evaluation of the diagnostic and therapeutic roles of non-coding RNA and cell proliferation related gene association in hepatocellular carcinoma

Micro RNA-34a-5p (miR-34a-5p) is an important molecule that can act as a modulator of tumor growth. It controls expression of a plenty of proteins controlling cell cycle, differentiation and apoptosis and opposing processes that favor viability of cancer cells, their metastasis and resistance to chemotherapy. Bioinformatics analysis indicated that minichromosome maintenance protein 2 (MCM2) is a target gene of miR-34a-p. In this study, RT-qPCR was employed to detect the expression of miR-34a-5p and MCM2 in 10 hepatocellular carcinoma (HCC) tissues. The functional role of miR-34a-5p in HCC was investigated and the interaction between miR-34a-5p and MCM2 was explored. Results showed miR-34a-5p expression in HCC tissues was significantly lower than in non HCC liver tissues (P < 0.05), but MCM2 expression in HCC tissues was markedly higher than in non HCC liver tissues (P < 0.05). In addition, miR-34a-5p expression was negatively related to MCM2 expression. To confirm effect of miR-34a-5p on tumor growth and its possible effect on MCM2, miR-34a-5p mimic and inhibitor was transfected into HCC cell lines (HepG2). MTS assay, showed miR-34a-5p over-expression could inhibit the proliferation of HCC cells. RT-qPCR was done to detect the expression of miR-34a-5p and MCM2 in HepG2 cells before and after transfection. Results showed that MCM2 expression in HCC tissues was markedly lower in mimic transfected group than in inhibitor transfected group and control group (P < 0.05) while miR-34a-5p expression in HepG2 cells was significantly higher in mimic transfected group than in inhibitor transfected group and control group (P < 0.05). Thus, miR-34a-5p may inhibit the proliferation of HCC cells via regulating MCM2 expression. These findings provide an evidence for the emerging role of microRNAs as diagnostic markers and therapeutic targets in HCC.

Benign odontogenic ghost cell lesions revisited and new considerations on dysplastic dentin.

This study aimed to revisit benign odontogenic ghost cell lesions (BOGCL) by hematoxylin and eosin staining and immunohistochemistry. Thirty cases of calcifying odontogenic cyst (COC) and 6 cases of dentinogenic ghost cell tumor (DGCT) were selected for histopathological and immunohistochemical analysis. Sections stained for cytokeratin (K) 14, K-19, amelogenin, collagen type 1 (COL-1), and dentin matrix acidic phosphoprotein 1 (DMP-1) were evaluated using qualitative analysis. Sections stained for Ki-67 and minichromosome maintenance protein-2 (MCM-2) were evaluated using semi-quantitative analysis. A morphologic overlap was noticed in all BOGCL. Moreover, no differences were detected in the expression of K-14 and K-19. The expression of proliferative markers Ki-67 and MCM-2 was similar between cystic and tumor lesions (p > .05). The presence of COL-1 and absence of amelogenin in the so-called dysplastic dentin, associated with its histologic pattern, suggest that this is in fact an enameloid-like tissue. The dysplastic dentin should be considered an enameloid-like tissue in these lesions. The similarity in histology, protein expression, and proliferative marker indices between COC and DGCT suggest that they are a sole entity and likely represent types of the same neoplasia.

Minichromosome maintenance protein 2 correlates with the malignant status and regulates proliferation and cell cycle in lung squamous cell carcinoma.

BackgroundMinichromosome maintenance protein 2 (MCM2), which is a member of MCM family, has been found to be a relevant marker for progression and prognosis in a variety of human cancers. Due to lack of effective therapeutic target in lung squamous cell carcinoma (LUSC) patients, the aim of our study was to screen and identify biomarkers which are associated to clinicopathological characteristics including prognosis in LUSC patients.MethodsThe expression status of MCM2 in lung cancer was analyzed using the publicly available Gene Expression Omnibus databases (GSE3268 and GSE10245). The mRNA and protein expression of MCM2 in lung cancer tissues and cell lines was detected by quantitative real-time PCR and Western blot, and the association between MCM2 expression and clinicopathological factors was analyzed by immunohistochemistry. The loss-of-function study of MCM2 was conducted in LUSC cell lines.ResultsIn our study, we found MCM2 expression was increased in LUSC tissues compared with paired adjacent normal lung tissues or lung adenocarcinoma tissues through analyzing microarray data sets (GSE3268 and GSE10245), which confirmed that MCM2 mRNA and protein were overexpressed in LUSC tissues and cell lines. Meanwhile, we analyzed the association between MCM2 protein expression and clinicopathological characteristics of LUSC patients, and found high expression of MCM2 protein was obviously associated with malign differentiated degree, advanced clinical stage, large tumor size, more lymph node metastasis and present distant metastasis. The survival analysis showed MCM2 overexpression was an independent unfavorable prognostic factor for LUSC patients.ConclusionMCM2 is involved in the development and progression of LUSC as an oncogene, and thereby may act as a potential therapeutic target for LUSC patients.

Cho/Cr ratio at MR spectroscopy as a biomarker for cellular proliferation activity and prognosis in glioma: correlation with the expression of minichromosome maintenance protein 2.

Magnetic resonance (MR) spectroscopy (1H-MRS) has been demonstrated to be useful in grading glioma, but the utility in assessing cellular proliferation activity and prognosis correlated with the expression of minichromosome maintenance protein 2 (MCM2) has not been reported. To explore the correlation between proton MR spectroscopy parameters (including choline [Cho]/creatine [Cr], N-acetyl aspartate [NAA]/Cr, and Cho/NAA ratios) and the expression of MCM2 and to further evaluate whether 1H-MRS can predict cell proliferative activity and provide prognostic information in high-grade gliomas (HGGs). Forty-three patients with histopathologically confirmed gliomas were involved in this study. All patients underwent 1H-MRS examination before surgery. Proliferative activity of gliomas was evaluated by MCM2 labeling index (LI). Pearson correlation analysis and empiric receiver operating characteristic (ROC) curves were performed. The Kaplan-Meier method and Cox regression were used for survival analysis. Significant correlation was observed between the Cho/Cr ratio and MCM2 LI ( r = 0.522, P < 0.01); however, there was no correlation between MCM2 LI and the Cho/NAA or NAA/Cr ratios ( r = 0.295, P = 0.55 and r = -0.042, P = 0.788, respectively). According to ROC analysis, MCM2 LI of 50% and Cho/Cr ratio of 2.68 represented the optimized cut-off values, respectively, to distinguish longer or shorter survival than 15 months in HGGs patients. Multivariate analysis revealed that both the Cho/Cr ratio and MCM2 expression were independent prognostic markers. Cho/Cr ratio has a potential in predicting the expression of MCM2 and can evaluate cell proliferative activity noninvasively. Both the Cho/Cr ratio and MCM2 expression are independent prognostic markers in patients with HGGs.

The expression and significance of minichromosome maintenance protein 2 in colorectal adenoma and colorectal carcinoma

Objective To explore the expression of minichromosome maintenance protein 2 (MCM2) in normal colorectal mucosa, colorectal adenomas and colorectal carcinoma, and to analyze the relationships among different histological types of colorectal adenomas and colorectal carcinoma. Methods Immunohistochemistry was used to exzamine the location and expression of MCM2 in the colorectal tissues, colorectal adenoma tissues and colorectal carcinoma tissues. Real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect MCM2 mRNA and connexin-32 mRNA expression. Results (1) Immunohistochemistry: The positive expression rate of MCM2 protein in normal colorectal mucosa, colorectal adenoma and colorectal carcinoma tissues was 16.7%, 55.0% and 80.0% respectively, with significant differences among them (P=0.031). The positive expression rate of MCM2 in tubular adenoma, mixed pattern of adenoma and villous adenoma was 40.0%, 65.0% and 75.0% respectively, also with significant differences among them (P=0.022). (2) FQ-PCR: The MCM2 mRNA expression in the normal colorectal mucosa, tubular adenoma, the mixed pattern of adenoma, villous adenoma, and colorectal carcinoma was 1.187±0.923, 4.126±1.339, 9.577±0.838, 22.150±4.077 and 48.020±4.811, respectively. The expression of MCM2 gradually increased in colorectal carcinoma, villous adenoma, the mixed pattern of adenoma, tubular adenoma, and normal colorectal mucosa (F=55.512, P=0.029). SNK multiple comparisons displayed that the differences about any two groups of the total mean showed statistical significance. Conclusion MCM2 is correlated with canceration of colorectal adenoma and the development of colorectal carcinoma. Detecting the expression of MCM2 can evaluate the progression of colorectal adenoma and the development of colorectal carcinoma. They may be the molecular biological indicators for predicting canceration of colorectal adenoma. Key words: Colorectal adenoma; Colorectal carcinoma; Immunohistochemistry; Minichromosome maintenance protein 2

A Phase II Randomized Trial of Lycopene-Rich Tomato Extract Among Men with High-Grade Prostatic Intraepithelial Neoplasia

A diverse body of evidence suggests that lycopene might inhibit prostate cancer development. We conducted a 6-mo repeat biopsy randomized trial among men with high-grade prostatic intraepithelial neoplasia (HGPIN). Here we report results for serum lycopene, prostate specific antigen (PSA) and insulin-like growth factor (IGF) proteins, histopathological review, and tissue markers for proliferation [minichromosome maintenance protein 2 (MCM-2)] and cell cycle inhibition (p27). Participants consumed placebo or tomato extract capsules containing 30 mg/day lycopene. Pre- and posttreatment biopsies were immunostained and digitally scored. Serum lycopene was determined by LC-MS-MS. In secondary analyses, pathologists blindly reviewed each biopsy to score histological features. Fifty-eight men completed the trial. Serum lycopene increased 0.55 μmol/L with treatment and declined 0.29 μmol/L with placebo. We observed no meaningful differences in PSA, IGF-1, or IGF binding protein 3 concentrations between groups, nor any differences in expression of MCM-2 or p27 in epithelial nuclei. Prevalences of cancer, HGPIN, atrophy, or inflammation posttreatment were similar; however, more extensive atrophy and less extensive HGPIN was more common in the lycopene group. Despite large differences in serum lycopene following intervention, no treatment effects were apparent on either the serum or benign tissue endpoints. Larger studies are warranted to determine whether changes observed in extent of HGPIN and focal atrophy can be replicated.Trial registration: ClinicalTrials.gov identifier: NCT00416325.

Antitumor activity of G-quadruplex-interactive agent TMPyP4 with photodynamic therapy in ovarian carcinoma cells.

The aim of the present study was to investigate the potential effects of photodynamic therapy (PDT) mediated by the cationic porphyrin, 5,10,15,20-tetra-(N-methyl-4-pyridyl)porphine (TMPyP4), on an ovarian carcinoma cell line and the underlying mechanisms by which TMPyP4-PDT exerts its actions. The analysis of cell viability, hematoxylin and eosin staining and flow cytometric apoptosis assays revealed that TMPyP4-PDT potently suppressed the growth of the A2780 cells in a laser energy- and dose-dependent manner. Mechanically, it was observed that TMPyP4-PDT suppressed the proliferation and motility of the A2780 cells. In addition, the expression levels of minichromosome maintenance protein-2 (MCM2) and carbonic anhydrase IX (CA-IX) were detected by western blot analysis. The results indicated that the TMPyP4-PDT-induced apoptosis and antimetastatic activity in the A2780 cells was accompanied by the inhibition of the expression of MCM2 and CA-IX. Therefore, TMPyP4-PDT may represent a potential therapeutic method for the treatment of ovarian carcinoma.

MCM-2 is a therapeutic target of Trichostatin A in colon cancer cells

Histone deacetylase (HDAC) inhibitors have recently emerged as a new class of anti-cancer agents. Trichostatin A (TSA), a classical HDAC inhibitor, has been demonstrated to induce cell cycle arrest, promote cell apoptosis, and inhibit metastasis. However, the molecular mechanism underlying TSA function has not been fully elucidated. In the current study, we found that TSA treatment induced altered expression of cell cycle-associated genes in HCT116 cells by RT-PCR array. Among the 84 genes related to cell cycle control, 34 genes were significantly altered by TSA treatment, with 7 genes upregulated and 27 genes downregulated. Interestingly, gene expression of minichromosome maintenance protein-2 (MCM-2) was significantly downregulated by TSA treatment. This was confirmed by quantitative RT-PCR and Western blotting. Moreover, silencing of MCM-2 by siRNA led to cell cycle arrest and apoptosis in HCT116 cells. In addition, TSA caused an increase of phosphorylated JNK, which was involved in downregulation of MCM-2. Together, our results suggest that MCM-2 is a noval therapeutic target of TSA in colon cancer cells.

MCM2 expression levels predict diagnosis and prognosis in gastric cardiac cancer.

Gastric Cardiac Cancer (GCC) has high incidence and poor prognosis requiring early screening of high-risk populations. Minichromosome maintenance (MCM) proteins are used as diagnostic-biomarkers in many cancers but not validated for GCC. We evaluate MCM protein 2 (MCM2), comparing it with the validated markers Ki67 and PCNA. GCC and corresponding cardiac precancerous samples were immunostained with Ki67, MCM2 and PCNA antibodies. 90% of dysplasia samples expressed MCM2, whereas Ki67 and PCNA were expressed in 67% and 80% respectively. The sensitivity and negative predictive values of MCM2 were also superior at 90% and 87%, respectively. Ki67 and PCNA expression was correlated with MCM2, but their expressions seldom reached surface layers, whereas MCM2 manifested mostly in easily accessible superficial layers. Labeling indices (LI) of Ki67 and PCNA were also lower. Significant associations between LI (MCM2), LI (PCNA), and TNM-stages, lymph node metastases and GCC grade were found (P<0.05). Increased protein expressions were associated with reduced overall and disease-free survival (P<0.05). Although Ki67 and PCNA were significant prognostic factors, there was no significant improvement in multivariate statistical analyses, in contrast to LI (MCM2) findings. MCM2 is a sensitive, specific and efficient biomarker of GCC having potential use in clinic.

Clinicopathologic significance of minichromosome maintenance protein 2 and Tat-interacting protein 30 expression in benign and malignant lesions of the gallbladder

Gallbladder cancers are aggressive tumors with a poor prognosis and high mortality rate. To find specific biological markers for early diagnosis and prognosis and to develop possible alternative treatment strategies, we examined minichromosome maintenance protein 2 (MCM2) and Tat-interacting protein 30 (TIP30) expression in 108 gallbladder adenocarcinomas, 15 gallbladder polyps, 35 chronic cholecystitis tissues, and 46 peritumoral tissues using immunohistochemistry. Expression of MCM2 was significantly higher in adenocarcinomas than in peritumoral tissues (χ² = 8.41; P < .01), adenomatous polyps (χ² = 6.81; P < .01), and chronic cholecystitis (χ² = 21.00; P < .01). In contrast, Tat-interacting protein 30 expression was significantly less in adenocarcinomas than in peritumoral tissues (χ² = 13.26; P < .01), adenomatous polyps (χ² = 4.76; P < .05), and chronic cholecystitis (χ² = 18.93; P < .01). The benign lesions in gallbladder epithelium with positive MCM2 or negative Tat-interacting protein 30 expression showed moderate to severe atypical hyperplasia. Expression of MCM2 and absence of Tat-interacting protein 30 were significantly associated with poor differentiation, large tumor mass, lymph node metastasis, and invasion of adenocarcinoma. Univariate Kaplan-Meier analysis showed that either elevated MCM2 (P = .006) or lowered Tat-interacting protein 30 (P = .006) expression was closely associated with shorter overall survival. Multivariate Cox regression analysis revealed that expression of MCM2 (P = .007) or nonexpression of Tat-interacting protein 30 (P = .009) was an independent predictor of a poor prognosis in adenocarcinoma. Our results suggest that overexpression of MCM2 or loss of expression of Tat-interacting protein 30 is closely related to carcinogenesis, progression, biological behavior, and prognosis of gallbladder adenocarcinoma.

Tumor recurrence following liver transplantation for hepatocellular carcinoma: Role of tumor proliferation status

The selection of patients with hepatocellular carcinoma for liver transplantation is currently based on the size and number of tumors to minimize the risk of recurrence. These criteria measure tumor bulk but may not reflect tumor behavior accurately. A biological marker of tumor behavior could aid with patient selection further. The aims of this study were to determine factors associated with a higher risk of tumor recurrence and to assess the role of tumor proliferation status with respect to recurrence following transplantation. Pathological data on 67 patients who underwent transplantation for hepatocellular carcinoma were reviewed, and tumor proliferation was assessed by minichromosome maintenance protein-2 (MCM-2) and cyclin A expression. A Cox regression analysis of factors related to tumor recurrence and overall survival was carried out. Recurrence-free survival was assessed according to compatibility with selection criteria, vascular invasion, and proliferation status. Tumor size, vascular invasion, and highest MCM-2 expression were associated with tumor recurrence by multivariate analysis (P < 0.02). Recurrence-free survival was significantly better for those patients without vascular invasion, those who were within the Milan, University of California San Francisco (UCSF), or Up-to-Seven selection criteria, and those with lower expression of MCM-2. In conclusion, tumors meeting the Milan, UCSF, or Up-to-Seven selection criteria had a lower rate of recurrence following liver transplantation. Vascular invasion and tumor proliferation status were associated with the risk of recurrence independently of tumor size. Biopsy of larger tumors to assess proliferative activity could identify those at lower risk of recurrence who could also benefit from liver transplantation.

Minichromosome maintenance protein-2-positive portal tract lymphocytes distinguish acute cellular rejection from hepatitis C virus recurrence after liver transplantation

Hepatitis C virus (HCV) is a leading indication for liver transplantation worldwide, but graft infection with HCV frequently leads to hepatic fibrosis. Acute cellular rejection (ACR) can be difficult to distinguish confidently from HCV, even with histology, but accurate diagnosis is critical because treatment of ACR may accelerate HCV-related graft injury. Immunohistochemistry was undertaken on 99 liver biopsies from 31 patients with HCV graft infection, 22 patients with ACR, and 11 patients with HCV infection and unexplained graft dysfunction to investigate whether lymphocyte expression of minichromosome maintenance protein-2 (Mcm-2), a marker of licensed cell cycle entry, assessed in a novel semiautomated system could distinguish between ACR and graft infection with HCV. The portal tract area was greater in ACR than in HCV graft infection (P = 0.027), but there was considerable overlap. However, both the number of Mcm-2-positive lymphocytes per portal tract and the number of Mcm-2-positive lymphocytes per millimeter squared of portal tract distinguished between ACR and HCV graft infection (P < 0.0001). A cutoff value of 107 positive cells per portal tract had a sensitivity of 81.8% and a specificity of 91.9% (positive predictive value of 66.67% and negative predictive value of 95.75%). Of 11 HCV-infected patients with an uncertain diagnosis, 7 were deemed ultimately to have HCV graft infection, and 4 had superimposed corticosteroid-responsive ACR. The number of Mcm-2-positive cells per portal tract and per millimeter squared of portal tract again distinguished clearly between the groups (P = 0.012). In conclusion, lymphocyte Mcm-2 expression is a useful adjunct to histology in differentiating between HCV graft infection and ACR. Patients with a low number of Mcm-2-positive portal tract lymphocytes are less likely to have ACR.

Determination of Potential Cellular Proliferation in the Odontogenic Epithelia of the Dental Follicle of the Asymptomatic Impacted Third Molars

The aim of this study is to determine the proliferative potentials of dental follicles (DF) of radiographically asymptomatic impacted third molar teeth by using Ki-67 and mini-chromosome maintenance protein 2 (MCM-2) proliferation markers, and to discuss whether there is any necessity for the removal of all impacted third molars by detecting the potential of the developing cysts and tumors of its DF. This study involved 59 DF of 54 patients referred for clinically and radiographically asymptomatic lower impacted third molars. Thirteen healthy gingiva tissues obtained during the impacted third molar operation in 13 patients served as a control group. DF widths on periapical radiographs below 2.5 mm were included in the study. The epithelial and mesenchymal components of DF were examined histologically. All specimens were stained with periodic acid Schiff, Alcian blue, and mucin for the evaluation of mucous cell prosoplasia. Epithelial cell proliferation was determined by using immunohistochemical labeling. The histologic examinations showed 11.9% mucous cell prosoplasia, 55.9% squamous metaplasia, 15.3% glandular epithelium, and 33.9% inflammation. Ki-67 expression was found to have higher values than MCM-2 expression in controls 6.15 (3.18) and 10.53 (5.77) and in DF 4.46 (1.39) and 5.89 (2.89), respectively. The expression of both proliferation markers in the basal epithelial cells, mucous, and squamous epithelium and inflammatory cells were statistically significant (P < .01). The results of this study indicate that the odontogenic epithelium in DF of asymptomatic impacted third molars might be actively proliferating and may be an indicator for the differentiation potential of DF. It would also seem that the inflammation observed in the mesenchymal components of DF up-regulate the cell turnover of odontogenic epithelium and lead to proliferation. Based on these observations, we support prophylactic removal of impacted third molars.

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.