Prognostic role of nm23 gene expression in patients with ovarian cancer

Correlation between NM23 protein overexpression and prognostic value and clinicopathologic features of ovarian cancer: a meta-analysis

OBJECTIVE

The prognostic value and clinicopathological features of NM23 (non-metastasis 23) have previously been assessed, but the results are controversial. Here, we attempted to clarify the correlation between NM23 expression and its prognostic value and the clinicopathological features in ovarian cancer (OC).

METHODS

The relevant studies were identified using PubMed, Embase, and Web of Science. We calculated the pooled odds ratio (OR) with 95% confidence intervals (CIs) for overall survival (OS), progression-free survival (PFS), and clinicopathological features. We used OS to evaluate the prognostic value of NM23 expression in patients with OC. Subgroup analyses were used to explore the source of heterogeneity.

RESULTS

We included 10 studies involving 894 patients in our assessment of the association between NM23 expression and OS for OC. Our data indicated that NM23 expression was not associated with improved OS (OR 0.83, 95% CI 0.41-1.68, P = 0.61) or PFS (OR 0.7, 95% CI 0.39-1.24, P = 0.22). Elevated NM23 expression was associated with differentiation grade (OR 0.35, 95% CI 0.2-0.6, P = 0.0002) and N status (OR 0.33, 95% CI 0.14-0.78, P = 0.01), whereas there was no significant difference between NM23 expression and tumor stage (OR 1.1, 95% CI 0.45-2.66, P = 0.84). Subgroup analysis did not reveal any potential source of heterogeneity. No obvious publication bias was found.

CONCLUSIONS

In OC, there is poor statistical significance between NM23 expression and OS and PFS, but NM23 expression is related to differentiation grade and N status. This meta-analysis reveals that NM23 expression is a potential factor of poor prognosis in OC. The prognostic role of NM23 in different OC stages in combination with the clinical characteristics suggests a novel approach for developing future therapeutic targets.

Regulatory functions of Nm23-H2 in tumorigenesis: insights from biochemical to clinical perspectives

Substantial effort has been directed at elucidating the functions of the products of the Nm23 tumor metastasis suppressor genes over the past two decades, with the ultimate goal of exploring their translational potentials in changing cancer patients' outcomes. Much attention has been focused on the better-known Nm23-H1, but despite having high sequence similarity, Nm23-H2 functions differently in many aspects. Besides acting as a metastasis suppressor, compelling data suggest that Nm23-H2 may modulate various tumor-associated biological events to enhance tumorigenesis in human solid tumors and hematological malignancies. Linkage to tumorigenesis may occur through the ability of Nm23-H2 to regulate transcription, cell proliferation, apoptosis, differentiation, and telomerase activity. In this review, we examine the linkages of Nm23-H2 to tumorigenesis in terms of its biochemical and structural properties and discuss its potential role in various tumor-associated events.

Metastasis suppressor genes

Metastasis is a major cause of cancer mortality. Metastasis is a complex process that requires the regulation of both metastasis-promoting and metastasis suppressor genes. The discovery of metastasis suppressor genes contributes significantly to our understanding of metastasis mechanisms and provides prognostic markers and therapeutic targets in clinical cancer management. In this review, we summarize the methods that have been used to identify metastasis suppressors and the potential clinical impact of these genes.

Metastasis-suppressor genes in clinical practice: lost in translation?

Over the past 25 years, an expanding set of metastasis-suppressor genes (MSGs) has been identified that specifically regulate metastasis formation without affecting primary growth. MSGs are involved in diverse molecular processes in multiple tumor types. Given the wealth of metastasis biology that underlies their functions, treatment strategies based on MSGs have an unparalleled potential to improve patient care. Using NM23 as a prime example, we discuss how specific MSGs have been used as prognostic markers, tools for predicting response to treatment, and targets for the development of novel therapies. Barriers specific to the translation of MSG biology into clinical practice are reviewed and future research directions necessary for clinical advances are delineated. Although to date the impact of MSGs on patient care is limited, it is an expanding field with vast potential to help develop new treatments and identify patients who will most benefit from them.

Expressions of nucleoside diphosphate kinase (nm23) in tumor tissues are related with metastasis and length of survival of patients with hepatocellular carcinoma

OBJECTIVE

To evaluate the relationship of expressions of nucleoside diphosphate kinase (nm23) and proliferating cell nuclear antigen (PCNA), as well as apoptosis, with the prognosis of HCC patients by analyzing their pathological and clinical data.

METHODS

The expressions of nm23 and PCNA were analyzed by immunohistochemistry and the apoptotic phenomena were detected by TUNEL technique in the liver samples from 43 HCC tissues, 39 para-neoplastic tissues, and 10 normal tissues. The mean apoptosis index (AI) and proliferative index (PI) in individual sample were calculated.

RESULTS

As shown by the detection, 32.6% of carcinomas had negative nm23 signal in tumor tissues, whereas all para-neoplastic and normal tissues had positive nm23. The AI in nm23 positive HCC was significantly higher than that in nm23 negative one, with statistical difference (P<0.05). Furthermore, the expressions of nm23, and the values of AI and PI were contrastively analyzed with some main pathological and clinical data of HCC. It revealed that HCC with extrahepatic metastasis showed remarkable correlation with the negative nm23 (P=0.013) and higher PI values of HCC (P=0.015). The disease-free survival in HCC patients with negative nm23 expression was significantly poorer than that in patients with positive nm23 expression.

CONCLUSIONS

These data suggest that expressions of nm23 protein in tumor tissues are correlated with occurrences of metastasis and length of survival of the HCC patients, which may be an indicator for their prognosis.

NM23 as a prognostic biomarker in ovarian serous carcinoma

The nm23 gene is a reported metastasis suppressor gene. Recent studies have shown that its expression has tissue specificity. The role of nm23 in human ovarian cancer is still controversial. This study examines the prognostic significance of nm23 expression in patients with serous ovarian carcinoma. Following comparative proteomics in 13 fresh frozen ovarian serous cancer tissues with other histological types of ovarian cancers, validation was performed using immunohistochemistry on clinically well-designed 73 ovarian serous carcinoma microarray samples that were retrieved from ovarian cancer patients from 1990 to 2003. Statistical analysis of the results was performed using chi(2) test, Cox proportional regression, the Kaplan-Meier method and log-rank test. We found that the expression of nm23 inversely correlated with peritoneal seeding (P=0.009). However, strong nm23 expression was associated with mortality in patients with ovarian carcinoma in univariate analysis (P=0.04). Poor prognostic factors of disease-free survival included tumor residue more than 2 cm (P=0.02), bilaterality (P=0.01) and peritoneal seeding (P<0.01), whereas poor prognostic factors affecting overall survival included peritoneal seeding (P=0.05). In Kaplan-Meier analysis, strong nm23 immunoreactivity correlates with poor overall survival (P=0.04) but not with poor disease-free survival. In conclusion, overexpression of nm23 is independently associated with decreased overall survival in patients with ovarian carcinoma and also significantly correlates with mortality. Nm23 may have a biological function that leads to poor clinical outcomes in ovarian carcinoma.

Prognostic impact of KI67, p53, human epithelial growth factor receptor 2, topoisomerase IIα, epidermal growth factor receptor, and nm23 expression of ovarian carcinomas and disseminated tumor cells in the bone marrow

Examination of tumor biological factors for prognostic and predictive indicators is not part of routine testing in ovarian cancer. As in other tumors, the detection of hematogenous tumor spread could help to estimate the risk of metastatic disease. We examined the expression of p53, KI67, topoisomerase IIα (Top IIa), epidermal growth factor receptor (EGFR), human epithelial growth factor receptor 2 (HER2) and nm23 in tumor tissues from 90 patients with ovarian cancer. All underwent bone marrow (BM) aspiration and screening for disseminated tumor cells in the bone marrow (DTC-BM) at primary diagnosis. BM aspiration, cytospin preparation, and immunocytochemical staining with the anticytokeratin antibody (A45-B/B3) were done following a standardized protocol. The expression of p53, KI67, Top IIa, EGFR, HER2, and nm23 was evaluated by immunohistochemistry on paraffin-embedded tissue samples and classified by percentage of stained cells or immunoreactive score (IRS). The prognostic impact of the individual factors together with standard histologic parameters was calculated by univariate and multivariate analyses. Expression rates for HER2 (2+/3+: 34.5%), KI67 (median 30%), p53 (median IRS 5), and Top IIa (median IRS 4) were relatively high, whereas nm23 (median IRS 2) and EGFR (IRS 0: 61%) showed weak staining. In 21/90 patients (23.3%), DTC-BM (≥1/2 × 106 cells) could be detected. The presence of DTC-BM was inversely related to nodal status (P= .015) but not to the other factors examined. Tumor stage (P= .02), lymph node involvement (P= .003), grade (P= .046), postoperative tumor residue (P <.001), peritoneal seeding (P= .02), and KI67 (P= .046) significantly correlated with overall survival (OS) after a median observation time of 28 months (2–105). The finding of ascites was borderline significant (P= .050). The presence of DTC-BM (P= .04) and KI67 positivity (P= .02) predicted reduced distant disease-free survival. By multivariate analysis, postoperative tumor residue remained an independent factor for OS (P= .02, relative risk = 4.6). As a primarily locoregional disease, tumor stage and postoperative tumor residue are the main determinants of prognosis in patients with ovarian cancer. However, even in advanced stages, examination of tumor biological factors could help to stratify subgroups of patients and establish targeted therapies.

Nm23-H1: a metastasis-associated gene

The protein product of nm23-H1 gene has activity of nucleoside diphosphate (NDP) kinase, which catalyzes the phosphorylation of nucleoside diphosphates to the corresponding nucleoside triphosphates. Reductions in nm23 expression have been significantly associated with aggressive behavior in melanoma, breast, colon, and gastric carcinomas. On the contrary, high levels of nm23 gene expression are noted in the advanced stage of thyroid carcinomas and associated with significant reductions in survival for neuroblastoma and osteosarcoma patients. Although expression of nm23/NDP kinase is divergent in various malignant tumors, its reduced expression seems to be related to increased metastatic potential in most carcinoma types. However, it is hypothesized that nm23 may play a tissue-specific role, and that different regulatory mechanisms may act in different tumors. In ovarian carcinoma, nm23-H1/NDP kinase may be correlated with some clinicopathologic characteristics. In cervical cancer, nm23-H1 is probably involved in cervical carcinogenesis and correlated with some aggressive parameters. Overexpression of nm23-H1 protein may indicate poor survival for cervical cancer patients. Other than histidine 118 residue (amino acid sequence 118: histidine) concerned with NDP kinase activity of nm23-H1, serine 120 (amino acid sequence 120: serine) related activity of histidine-dependent protein phosphotransfer was recently reported to be responsible for its biological suppressive effects. To inhibit metastatic potential, nm23-H1 is also demonstrated to co-immunoprecipitate the kinase suppressor of Ras and phosphorylate it, and therefore reduce activation of the extracellular signal-regulated kinase mitogen-activated protein kinase pathway in response to signaling.

SET complex in serous epithelial ovarian cancer

With low cure rates but increasing diverse treatment options that provide variable remission times, ovarian cancer is increasingly being recognized as a chronic disease. This reality indicates the need for a better understanding of factors influencing disease progression. In a previous global analysis of gene expression, we identified genes differentially expressed when comparing serous epithelial ovarian tumors of low and high malignant potential (grade 0 vs grade 3). In this analysis, 4 out of 5 members of the SET complex, SET, APE1, NM23 and HMGB2, were highly expressed in invasive grade 3 tumors. To further investigate the expression of these genes and the fifth member of the SET complex (pp32), we performed immunohistochemistry, on a tissue array composed of 235 serous tumors of different grades and disease stages. A significant correlation between expression of all SET complex proteins and the tumor differentiation was observed (p < 0.05). When combining all tumors, overexpression of Nm23 (p = 0.04), Set (p = 0.004) and Ape1 (p = 0.004) was associated with the clinical stage of the disease. No marker by itself was associated with prognosis. The combination of a high level of Nm23 in the context of a low level of Set compared to all other combinations of these markers did confer a better prognosis (p = 0.03). When combined, high expression of Hmgb2 and low expression of Ape1 was also associated with patient prognosis (p = 0.05). These findings suggest that a strategy that sums the activities of different partners within a pathway may be more appropriate in designing nomograms for patient stratification.

Identification of ATF-3, caveolin-1, DLC-1, and NM23-H2 as putative antitumorigenic, progesterone-regulated genes for ovarian cancer cells by gene profiling

Although progesterone (P4) has been implicated to offer protection against ovarian cancer (OCa), little is known of its mechanism of action. The goal of this study was to identify P4-regulated genes that have anti-OCa action. Three immortalized nontumorigenic human ovarian surface epithelial (HOSE) cell lines and three OCa (OVCA) cell lines were subjected to 5 days of P4 treatment. Transcriptional profiling with a cDNA microarray containing approximately 2400 known genes was used to identify genes (1) whose expression was consistently downregulated in OVCA cell lines compared to HOSE cell lines, and (2) whose expression was restored in OCa cell lines by P4 treatment. From the candidates selected, activating transcription factor-3 (ATF-3), caveolin-1, deleted in liver cancer-1 (DLC-1), and nonmetastatic clone 23 (NM23-H2) were chosen for post hoc functional studies based on their previously reported action as tumor suppressors or apoptosis inducers. Semiquantitative RT-PCR analyses confirmed loss of or reduced transcription of these genes in OVCA cells when compared to HOSE cells and their upregulation following P4 treatment. Hormonal specificity was demonstrated by blockade experiments with a progestin antagonist RU 38486. Ectopic expression of caveolin-1, DLC-1, and NM23-H2 caused growth inhibition in OVCA cell cultures, but not in HOSE cell cultures, while forced expression of ATF-3 suppressed growth in both. Overexpression of AFT-3 also enhanced caspase-3 activity in both HOSE and OVCA cells, whereas ectopic expression of caveolin-1 and DLC-1 only activated this enzyme in OCa cells. In contrast, NM23-H2 overexpression was ineffective in activating caspase-3. Overexpression of any of the four genes in OCa cells reduced soft-agar colony formation and cell invasiveness. Taken together, we have identified four new P4-regulated, antitumor genes for OCa. However, their modes of action differ significantly; ATF-3 primarily functions as an apoptosis inducer, NM23-H2 as a suppressor of cell motility, and caveolin-1 and DLC-1 exhibiting features of classical tumor suppressors. To the best of our knowledge, except for NM23-H2, this is the first report linking P4 to the regulation of these tumor suppressor/proapoptotic genes, which could serve as future therapeutic targets.

Metastasis in pleural mesothelioma. Immunohistochemical markers for disseminated disease

AIMS

To examine 13 cases of mesothelioma with metastases and compare these with 29 biopsy samples of patients without metastases. Metastatic disease was defined as tumour in which tumour appeared in a different cavity/tissue of the body and which showed no direct spread. Consequently, mediastinal nodal and parenchymal lung spread was excluded.

METHODS AND RESULTS

Standard sections were prepared and stained according to the manufacturers' protocols. The antibodies used were MIB-1, nm23, Bcl-2, MMP-9, EMMPRIN (CD147) and alpha-catenin. Scoring employed a grading system (0/1/2/3), and was performed by two pathologists independently. The tissues revealed no significant staining differences for MIB-1, Bcl-2, MMP-9 or EMMPRIN, and therefore no linkage to metastatic potential was determined. Alpha-Catenin showed a diminished level of expression in cases of metastatic mesothelioma (P = 0.024), possibly reflecting dimished catenin-cadherin binding and paralleling data from other tumours. nm23 showed greater staining in metastatic tumours when compared with the controls (P = 0.001). Intriguingly, the nm23 staining pattern was the reverse of that expected. This reversed pattern has been noted before in other tumours and therefore a biological prognostic event may exist for this antibody test and mesothelioma metastasis.

CONCLUSION

There may be a place for nm23 and possibly alpha-catenin in immunohistochemical assessment of mesothelioma metastatic potential. However, MIB-1, Bcl-2, MMP-9 and EMMPRIN (CD147) do not show significant staining results.

Gene expression profiles predict survival and progression of pleural mesothelioma

PURPOSE

Clinical outcomes for malignant pleural mesothelioma (MPM) patients having surgery are imprecisely predicted by histopathology and intraoperative staging. We hypothesized that gene expression profiles could predict time to progression and survival in surgically cytoreduced pleural mesothelioma of all stages.

EXPERIMENTAL DESIGN

Gene expression analyses from 21 MPM patients having cytoreductions and identical postoperative adjuvant therapy were performed using the U95 Affymetrix gene chip. Using both dChip and SAM, neural networks constructed a common 27 gene classifier, which was associated with either the high-risk and low-risk group of patients. Data were validated using real-time PCR and immunohistochemical staining. The 27 gene classifier was also used for validation in a separate set of 17 MPM patients from another institution.

RESULTS

The groups predicted by the gene classifier recapitulated the actual time to progression and survival of the test set with 95.2% accuracy using 10-fold cross-validation. Clinical outcomes were independent of histology, and heterogeneity of progression and survival in early stage patients was defined by the classifier. The gene classifier had a 76% accuracy in the separate validation set of MPMs.

CONCLUSIONS

These data suggest that pretherapy gene expression analysis of mesothelioma biopsies may predict which patients may benefit from a surgical approach.

Gene expression profiling of colon cancer by DNA microarrays and correlation with histoclinical parameters

Different diagnostic and prognostic groups of colorectal carcinoma (CRC) have been defined. However, accurate diagnosis and prediction of survival are sometimes difficult. Gene expression profiling might improve these classifications and bring new insights into underlying molecular mechanisms. We profiled 50 cancerous and noncancerous colon tissues using DNA microarrrays consisting of approximately 8000 spotted human cDNA. Global hierarchical clustering was to some extent able to distinguish clinically relevant subgroups, normal versus cancer tissues and metastatic versus nonmetastatic tumours. Supervised analyses improved these segregations by identifying sets of genes that discriminated between normal and tumour tissues, tumours associated or not with lymph node invasion or genetic instability, and tumours from the right or left colon. A similar approach identified a gene set that divided patients with significantly different 5-year survival (100% in one group and 40% in the other group; P=0.005). Discriminator genes were associated with various cellular processes. An immunohistochemical study on 382 tumour and normal samples deposited onto a tissue microarray subsequently validated the upregulation of NM23 in CRC and a downregulation in poor prognosis tumours. These results suggest that microarrays may provide means to improve the classification of CRC, provide new potential targets against carcinogenesis and new diagnostic and/or prognostic markers and therapeutic targets.

Comparison of the usefulness between a new universal grading system for epithelial ovarian cancer and the FIGO grading system

OBJECTIVE

The aim of this study was to compare the usefulness of a new universal grading system for ovarian cancer proposed by Shimizu et al. (Cancer 82 (1998), 893; Gynecol. Oncol. 70 (1998), 2) with that of the FIGO grading system as a prognostic factor of ovarian cancer.

METHODS

We reviewed all paraffin-embedded tissues of epithelial ovarian cancer obtained from 130 women who underwent initial treatment including primary surgery in our hospital between January 1990 and December 2000. The scores of the specimens were obtained according to both the universal grading system and the FIGO grading system.

RESULTS

Both the FIGO grading system and the universal grading system worked as significant prognostic indicators. Patients with Grades 1 and 3 of the universal grading system had high and low 5-year survival rates, respectively, compared to those of the FIGO grading system. Inconsistencies in histologic grade between the FIGO and universal grading systems were observed in 22 patients. The positive rate of lymph node metastasis in patients with Grade 3 of the universal grading system was significantly high compared to those of the FIGO grading system (P = 0.03). Patients with Grade 3 of the universal grading system with residual tumor of not less than 2 cm in diameter were observed more frequently than those of the FIGO grading system. C4ONCLUSION: The universal grading system was superior to the FIGO grading system in terms of the prediction of malignancies such as the potential of lymph node metastasis and invasion and the adaptability to clear cell cancer.