High levels of Nm23 gene expression in advanced stage of thyroid carcinomas

TIF1γ and SMAD4 regulation in colorectal cancer: impact on cell proliferation and liver metastasis

We investigated the effects of transcriptional intermediary factor 1γ (TIF1γ) and SMAD4 on the proliferation and liver metastasis of colorectal cancer (CRC) cells through knockdown of TIF1γ and/or SMAD4 and knockdown of TIF1γ and/or restoration of SMAD4 expression. Furthermore, we examined TIF1γ and SMAD4 expression in human primary CRC and corresponding liver metastatic CRC specimens. TIF1γ promoted but SMAD4 inhibited the proliferation of CRC cells by competitively binding to activated SMAD2/SMAD3 complexes and then reversely regulating c-Myc, p21, p27, and cyclinA2 levels. Surprisingly, both TIF1γ and SMAD4 reduced the liver metastasis of all studied CRC cell lines via inhibition of MEK/ERK pathway-mediated COX-2, Nm23, uPA, and MMP9 expression. In patients with advanced CRC, reduced TIF1γ or SMAD4 expression was correlated with increased invasion and liver metastasis and was a significant, independent risk factor for recurrence and survival after radical resection. Patients with advanced CRC with reduced TIF1γ or SAMD4 expression had higher recurrence rates and shorter overall survival. TIF1γ and SMAD4 competitively exert contrasting effects on cell proliferation but act complementarily to suppress the liver metastasis of CRC via MEK/ERK pathway inhibition. Thus, reduced TIF1γ or SMAD4 expression in advanced CRC predicts earlier liver metastasis and poor prognosis.

Genetic alterations in thyroid cancer mediating both resistance to BRAF inhibition and anaplastic transformation

A subset of thyroid cancers present at advanced stage or with dedifferentiated histology and have limited response to standard therapy. Tumors harboring the BRAF V600E mutation may be treated with BRAF inhibitors; however, tumor response is often short lived due to multiple compensatory resistance mechanisms. One mode of resistance is the transition to an alternative cell state, which on rare occasions can correspond to tumor dedifferentiation. DNA sequencing and RNA expression profiling show that thyroid tumors that dedifferentiate after BRAF inhibition are enriched in known genetic alterations that mediate resistance to BRAF blockade, and may also drive tumor dedifferentiation, including mutations in the PI3K/AKT/MTOR (PIK3CA, MTOR), MAP/ERK (MET, NF2, NRAS, RASA1), SWI/SNF chromatin remodeling complex (ARID2, PBRM1), and JAK/STAT pathways (JAK1). Given these findings, recent investigations have evaluated the efficacy of dual-target therapies; however, continued lack of long-term tumor control illustrates the complex and multifactorial nature of these compensatory mechanisms. Transition to an immune-suppressed state is another correlate of BRAF inhibitor resistance and tumor dedifferentiation, suggesting a possible role for concurrent targeted therapy with immunotherapy. Investigations into combined targeted and immunotherapy are ongoing, but early results with checkpoint inhibitors, viral therapies, and CAR T-cells suggest enhanced anti-tumor immune activity with these combinations.

NDPKA is not just a metastasis suppressor - be aware of its metastasis-promoting role in neuroblastoma

NDPK-A, encoded by nm23-H1 (also known as NME1) was the first metastasis suppressor discovered. Much of the attention has been focused on the metastasis-suppressing role of NDPK-A in human tumors, including breast carcinoma and melanoma. However, compelling evidence points to a metastasis-promoting role of NDPK-A in certain tumors such as neuroblastoma and lymphoma. To balance attention on this contrariety of NDPK-A in different cancer types, this review addresses the metastasis-promoting role of NDPK-A in neuroblastoma. Neuroblastoma is an embryonic tumor, arising from neural crest cells that fail to differentiate into the sympathetic nervous system. We summarize and discuss nm23-H1 genetics and the prognosis of neuroblastoma, structural and functional changes associated with the S120G mutation of NDPK-A, as well as the evidence supporting the role of NDPK-A as a metastasis promoter. Also discussed are the NDPK-A relevant molecular determinants of neuroblastoma metastasis, and metastasis-relevant neural crest development. Because of NDPK-A's dichotomous role in tumor metastasis as both a suppressor and a promoter, tumor genome/exome profiles are necessary to identify the molecular drivers of metastasis in the NDPK-A network for developing tumor-specific therapies.

Expression of nm23-H1 and COX-2 in thyroid papillary carcinoma and microcarcinoma

The expression of non-metastatic expressed/non-metastatic 23 nucleoside diphosphate kinase 1 (nm23-H1) and cyclooxygenase 2 (COX-2) proteins in thyroid carcinoma have been analysed in a number of previous studies, but this requires further study. The current study focused on the expression levels of nm23-H1 and COX-2 in 130 human thyroid papillary carcinoma (PTC) tissues. Of the 130 PTC tissues, 55 were classified as microcarcinoma and may provide information on the development of the specific characteristics of this tumour type. Routine histopathological examination and immunohistochemical detection of nm23-H1 and COX-2 expression was performed on 130 PTC tissues from patients treated in the Clinical Hospital for Tumours (Zagreb, Croatia) between January 2000 and December 2007. The stain intensity of nm23-H1 and COX-2 proteins was compared with the characteristics of the patients and the tumour. The highest overall expression rate of nm23-H1 and COX-2 was 90 and 67.6%, respectively, and the joint expression of these proteins was statistically significant. The median expression level of nm23-H1 was significantly increased in the classical and follicular histological group of the PTC tissues compared with tissues from other histological groups. The median expression level of COX-2 was significantly increased in the follicular histological group, and reduced in the diffuse-sclerosing group of PTC tissues. All the metastatic microcarcinoma tissues had increased expression levels of the two proteins in comparison with microcarcinoma tissues without lymph node metastases; however, this variation was only statistically significant for COX-2 expression levels. Therefore the results of the current study indicate that COX-2 protein levels may be able to differentiate which thyroid papillary microcarcinoma tumours possess metastatic potential.

Characteristics of a thyroid carcinoma cell line derived from spinal metastasis

We established and characterized a new thyroid cancer cell line came from patients who presented spine metastasis; these cell lines could thus be new in vivo models for studying the biology including metastasis of thyroid cancer.

A thyroid carcinoma cell line named THY28 was established through primary culture of the surgical specimens, which were derived from a Chinese patient with spinal metastasis. The cell morphology, growth kinetics, cell cycle, chromosome number, cell capability of migration, tumorigenicity and cytogenetic features of the cell line were investigated. THY28 cells were subcultured in vitro for more than 50 passages with a human karyotype. The modal number of its chromosomes was mainly from 67 to 85. The doubling time of THY28 cells was 56 hours. The histopathological features of xenograft induced by THY28 cells were consistent with the characteristics of thyroid cancer. The biological and molecular properties of THY28 cells were not entirely consistent with those of other thyroid carcinoma cells such as SW579 and TT cells, indicating biological differences between primary and metastatic thyroid carcinoma cell lines. We have established a novel thyroid carcinoma cell line derived from spinal metastasis, which will provide a useful model for biological or therapeutic studies of thyroid carcinoma metastasis.

Regulation of the metastasis suppressor Nm23-H1 by tumor viruses

Metastasis is the most common cause of cancer mortality. To increase the survival of patients, it is necessary to develop more effective methods for treating as well as preventing metastatic diseases. Recent advancement of knowledge in cancer metastasis provides the basis for development of targeted molecular therapeutics aimed at the tumor cell or its interaction with the host microenvironment. Metastasis suppressor genes (MSGs) are promising targets for inhibition of the metastasis process. During the past decade, functional significance of these genes, their regulatory pathways, and related downstream effector molecules have become a major focus of cancer research. Nm23-H1, first in the family of Nm23 human homologues, is a well-characterized, anti-metastatic factor linked with a large number of human malignancies. Mounting evidence to date suggests an important role for Nm23-H1 in reducing virus-induced tumor cell motility and migration. A detailed understanding of the molecular association between oncogenic viral antigens with Nm23-H1 may reveal the underlying mechanisms for tumor virus-associated malignancies. In this review, we will focus on the recent advances to our understanding of the molecular basis of oncogenic virus-induced progression of tumor metastasis by deregulation of Nm23-H1.

Protein marker profiling in different T classification in laryngeal squamous cell carcinoma

BACKGROUND

The identification of specific biomarkers related to laryngeal squamous cell carcinoma (SCC) will be helpful in early detection and determination of reasonable treatment options, which are crucial for the prognosis of patients with laryngeal SCC. The purpose of this study was to profile the protein markers that can be used for diagnosis and prognosis of laryngeal SCC and to observe laryngeal SCC progression with distinct stages of malignant transformation.

METHODS

Two hundred twenty-five proteins were tested in 84 pairs of tumors and adjacent nontumor mucosa samples using protein pathway arrays (PPAs). Ingenuity pathway analysis (IPA) enrichment analysis was performed and protein expression profiles in different T classification were mapped by grid analysis of time-series expression (GATE).

RESULTS

Among 16 proteins differently expressed between tumors and normal tissues, we selected 9 proteins (TTF-1, CDK2, Eg5, proliferating cell nuclear antigen [PCNA], Bcl-xL, 14-3-3β, p27, SRC-1, cytokeratin 18) as markers for classification. From the IPA analysis, we observed a more malignant transformation from T3 to T4 at the protein level and described the changing patterns of the proteins' expression in this progression. JAK2, keratin 10, and IL-3Rα were identified as markers for prognosis. The risk model based on histological grade, T classification, N classification, JAK2, and IL-3Rα can predict the prognosis with 85.5% accuracy.

CONCLUSION

This study indicated that dysregulated signaling proteins can be selected as useful biomarkers for tumor classification and predicting the outcome in patients with laryngeal SCC. The changing patterns of the proteins' expression in different stages were related to the more malignant transformation and further studies will focus on the role of these proteins in laryngeal SCC progression.

Nm23-H1 nuclear expression is associated with a more favourable prognosis in laryngeal carcinoma: univariate and multivariate analysis

AIMS

To use image analysis and multivariate analysis to investigate the prognostic significance of Nm23-H1 subcellular localization in a large cohort of laryngeal squamous cell carcinomas (LSCCs).

METHODS AND RESULTS

Nm23-H1 total and nuclear levels were immunohistochemically determined and calculated with an image analysis system in 104 consecutively operated LSCCs. The mean follow-up was 58.3 ± 35.1 months (median 45 months). Total Nm23-H1 levels correlated only with patient stratification by pT (P=0.01). Mean nuclear Nm23-H1 levels were lower in patients with recurrent disease (P=0.01), and disease-free survival (DFS) was longer in patients whose nuclear levels of Nm23-H1 were >2.0% than in those with levels ≤ 2.0% (P=0.019). On multivariate analysis, Nm23-H1 nuclear expression [hazard ratio (HR) 2.59, P=0.005] and N stage (HR 3.60, P=0.0001) were prognostically significant in relation to DFS.

CONCLUSIONS

In LSCC, Nm23-H1 nuclear expression may be useful for identifying patients at higher risk of recurrence after treatment and who might be considered for more aggressive therapy. Further investigations are needed before Nm23-H1 can be considered for use in targeted treatments for LSCC.

Clinical significance of serum biomarkers in pediatric solid mediastinal and abdominal tumors

Childhood cancer is the leading cause of death by disease among U.S. children between infancy and age 15. Despite successes in treating solid tumors such as Wilms tumor, disappointments in the outcomes of high-risk solid tumors like neuroblastoma have precipitated efforts towards the early and accurate detection of these malignancies. This review summarizes available solid tumor serum biomarkers with a special focus on mediastinal and abdominal cancers in children.

Nuclear localization of Nm23-H1 in head and neck squamous cell carcinoma is associated with radiation resistance

BACKGROUND

Although radiation resistance is a primary issue in radiation therapy, attempts to find predictors of radiation resistance have met with little success. The authors therefore aimed to determine predictors for radiation resistance to improve the prognosis of head and neck squamous cell carcinoma (HNSCC).

METHODS

HNSCC cell lines, SCC15, SCC25, and QLL1, irradiated with an acute dose of 4 grays (Gy) (RR-4), a cumulative dose of 60 Gy (RR-60), and a booster dose of 4 Gy over 60 Gy (RR-60 + 4), were used with nonirradiated cell lines. Those were used in cDNA microarray, proteomics, Western blotting, and immunofluorescence, respectively. One hundred five HNSCC tissue samples with radiation resistance were analyzed by immunohistochemistry.

RESULTS

Western blot analysis of RR-60 cell lines was identical to the data of Nm23-H1 overexpression by cDNA array and proteomic screening. Immunofluorescence demonstrated significant nuclear translocation of Nm23-H1 in RR-4 and RR-60 cell lines, and less but still intense nuclear shuttling in RR-60 + 4. Similarly, Nm23-H1 nuclear localization was observed in 20% (21 of 105) of tissue samples. Univariate analysis demonstrated that Nm23-H1 nuclear localization was strongly associated with overall and recurrence-free survival. Multivariate stepwise Cox regression analysis showed that Nm23-H1 nuclear localization (odds ratio [OR], 7.48) and N stage (OR, 2.13) were associated with overall survival, and Nm23-H1 nuclear localization (OR, 3.02), T stage (OR, 1.43), and insufficient tumor margin (OR, 3.27) were associated with recurrence-free survival.

CONCLUSIONS

Overexpression of Nm23-H1, specifically its nuclear translocation, may be a powerful predictor of radiation resistance in HNSCC.

Antimetastatic role of Smad4 signaling in colorectal cancer

BACKGROUND & AIMS

Transforming growth factor (TGF)-beta signaling occurs through Smads 2/3/4, which translocate to the nucleus to regulate transcription; TGF-beta has tumor-suppressive effects in some tumor models and pro-metastatic effects in others. In patients with colorectal cancer (CRC), mutations or reduced levels of Smad4 have been correlated with reduced survival. However, the function of Smad signaling and the effects of TGF-beta-receptor kinase inhibitors have not been analyzed during CRC metastasis. We investigated the role of TGF-beta/Smad signaling in CRC progression.

METHODS

We evaluated the role of TGF-beta/Smad signaling on cell proliferation, migration, invasion, tumorigenicity, and metastasis in Smad4-null colon carcinoma cell lines (MC38 and SW620) and in those that transgenically express Smad4. We also determined the effects of a TGF-beta-receptor kinase inhibitor (LY2109761) in CRC tumor progression and metastasis in mice.

RESULTS

TGF-beta induced migration/invasion, tumorigenicity, and metastasis of Smad4-null MC38 and SW620 cells; incubation with LY2109761 reversed these effects. In mice, LY2109761 blocked metastasis of CRC cells to liver, inducing cancer cell expression of E-cadherin and reducing the expression of the tumorigenic proteins matrix metalloproteinase-9, nm23, urokinase plasminogen activator, and cyclooxygenase-2. Transgenic expression of Smad4 significantly reduced the oncogenic potential of MC38 and SW620 cells; in these transgenic cells, TGF-beta had tumor suppressor, rather than tumorigenic, effects.

CONCLUSIONS

TGF-beta/Smad signaling suppresses progression and metastasis of CRC cells and tumors in mice. Loss of Smad4 might underlie the functional shift of TGF-beta from a tumor suppressor to a tumor promoter; inhibitors of TGF-beta signaling might be developed as CRC therapeutics.

Nm23-H1/nucleoside diphosphate kinase as a key molecule in breast tumor angiogenesis

BACKGROUND

Neo-angiogenesis seems to be a critical feature of breast tumor growth, migration and metastasis. Inhibition of angiogenesis may provide information regarding treatment. Since angiogenesis is the result of complex processes, controlled by several angiogenic (pro- and/or -anti) factors and their receptors, multiple ways to prevent or retrogress tumor-induced angiogenesis have been proposed. The clinically significant activity of bevacizumab and other antiangiogenic treatments have attracted a great deal of interest.

OBJECTIVE/METHODS

We discuss biological aspects of breast cancer angiogenesis and nucleoside diphosphate kinase (NDPK) as a key molecule in this process.

RESULTS/CONCLUSIONS

In clinical and experimental trials, it was reported that NDPK is inversely related to breast cancer metastasis and angiogenesis. To inhibit the metastatic potential of cancer cells, Nm23-H1/NDP kinase appears to interact with many proteins involved in cellular signal transduction in angiogenesis and tumorigenesis, and therefore reduces the activation of the extracellular signal-regulated kinase (ERK)/MAPK in response to those signals.

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.

Read-through transcript from NM23-H1 into the neighboring NM23-H2 gene encodes a novel protein, NM23-LV

NM23-H1 and NM23-H2 are neighboring genes on chromosome 17q. They encode nucleoside diphosphate kinases that have additional roles in signal transduction, transcription, and apoptosis. NM23-H1 expression is a strong marker for prognosis and metastatic behavior in many tumor types. A new bioinformatic tool, TranscriptView, identified read-through transcripts that start in the NM23-H1 gene and continue in the neighboring NM23-H2 gene. Splicing results in a transcript containing exons 1 to 4 of NM23-H1 and exons 2 to 5 of NM23-H2. The resulting mRNA encodes a novel and long variant of the NM23 protein family, NM23-LV, which contains part of NM23-H1 and the complete NM23-H2 protein. The transcript was amplified and sequenced from two neuroblastoma cell lines, confirming the presence of the predicted NM23-LV mRNA in vivo. Tissue analysis showed that NM23-LV is ubiquitously expressed, with the exception of the kidney. Neuroblastoma tumors show high-level expression of NM23-H1 and-H2 as well as NM23-LV mRNA. In neuroblastoma cells, the NM23-LV protein has mainly a cytoplasmic localization, but some nuclear staining was observed as well.

The intratumoral microvessel density and expression of bFGF and nm23-H1 in colorectal cancer

It has previously been reported that intratumoral microvessel density (IMD), and the expression of bFGF and nm23-H1 are useful prognostic markers in colorectal cancer (CRC). In this study, a total of 100 CRCs were evaluated histopathologically, and IMD, bFGF and nm23-H1 expression were assessed by immunohistochemistry. IMD of patients increased with grade and stage, and this increase was statistically significant (p<0.05). A significantly higher incidence of high bFGF expression scores was also associated with increasing grade and stage (p<0.05). However, there was no significant difference between the grades in nm23-H1 expression (p=0.234). nm23-H1 expression occurred with lower incidence in stages C1, C2 and D than in stages B1 and B2 (p<0.05). Thus, a negative correlation was found between nm23-H1 expression and stage or lymph node metastasis (LNM) (p<0.05). IMD and bFGF expression were positively correlated with grade, stage, LNM, and lymphovascular invasion. Although positive correlation was found between IMD and bFGF, nm23-H1 expression negatively correlated with both of them. As a result, in clinical practice, increased IMD and bFGF expression and decreased nm23-H1 expression may provide valuable information in characterizing the malignant phenotype.

Down-regulated nucleoside diphosphate kinase nm23-H1 expression is unrelated to high-risk human papillomavirus but associated with progression of cervical intraepithelial neoplasia and unfavourable prognosis in cervical cancer

OBJECTIVE

One of the factors leading to an invasive phenotype is the nm23 family of metastases-associated genes. Of the six known members, nm23-H1 is the most frequently studied potential anti-metastatic gene in cervical cancer. However, the possible molecular links to oncogenic human papillomavirus (HPV) are completely unexplored as yet.

MATERIALS AND METHODS

As a part of the HPV-Pathogen Istituto Superiore di Sanità study, a series of 150 squamous cell carcinomas (SCCs) and 152 cervical intraepithelial neoplasia (CIN) lesions were examined by immunohistochemical staining for nm23-H1, and tested for HPV by polymerase chain reaction (PCR) with three sets of primers (MY09/11, GP5(+)/GP6(+) and short PCR fragment). Follow-up data were available on all patients with SCC, and 67 CIN lesions were monitored by serial PCR for clearance or persistence of HPV after cone treatment.

RESULTS

A linear decrease (p = 0.001) was observed in nm23-H1 expression, starting from CIN1 (85% with normal expression), with the most dramatic down regulation on transition from CIN2 (70% normal) to CIN3 (39%) and further to SCC (25%). Reduced expression was associated with CIN3 or cancer at an odds ratio 8.72 (95% confidence interval 4.13 to 18.41). Nm23-H1 was of no use as a marker of the high-risk human papillomavirus (HR-HPV) type, and it did not predict clearance or persistence of HR-HPV after treatment of CIN. Importantly, nm23-H1 expression was a significant prognostic factor in cervical cancer, reduced expression being associated with lower survival (p = 0.022) in univariate analysis. In the multivariate (Cox) regression model, however, only the International Federation of Gynecology and Obstetrics stage (p = 0.001) and age (p = 0.011) remained independent prognostic predictors.

CONCLUSIONS

Down-regulated nm23-H1 expression is markedly associated with progression from CIN2 to CIN3, and predicts poor prognosis in cervical cancer. Nm23-H1 down regulation is probably orchestrated by mechanisms independent of HR-HPV oncoproteins and is possibly related to the emergence of a proteolytic phenotype.

Diagnostic molecular markers in thyroid cancer

The use of molecular assays to analyze clinical tissues in the diagnosis and management of thyroid cancer, similar to other tumors, will likely allow for more accurate characterization of the aggressiveness of individual tumors and may allow for the early diagnosis of recurrence. The application of these methods to thyroid nodules and nodal metastases is less encumbered by difficulties arising from amplification of transcripts in non-thyroid cells. For these tissues, these assays are likely to be used clinically in the near-future. New data arising from cDNA arrays identifying novel markers of malignancy or tumor aggressiveness make this a growing area of interest. The use of molecular assays in diagnosing distant metastases is more problematic due to issues with ectopic expression of either full length or splice variants of genes thought to be thyroid-specific. Assay quantitation is a complex problem owing to variability in the level of expression of "housekeeping" genes and the variety of phlebotomy and RT-PCR methods reported. Additional research in this area is clearly required before a recommendation can be given regarding clinically applicability of these tests.

[Anaplastic thyroid carcinoma. Our experience]

Anaplastic thyroid cancer ranks among the most lethal of all known human malignancies, and remains almost uniformly fatal. It represents approximately 1% of all thyroid carcinomas.

MATERIALS AND METHODS

A retrospective study was performed including all anaplastic thyroid carcinoma cases diagnosed in our institution between 1989 and 2000.

RESULTS

We collected 15 cases previously biopsied as anaplastic thyroid carcinoma. Three of them were treated with a curative intention; different palliative modalities were carried out for the remaining cases. None of the cases survived more than 1 year, and the median survival time was 3.5 months.

DISCUSSION/CONCLUSION

This study confirms the previously known aggressiveness of this neoplasm, in which the prognosis and evolution remain to be fatal.

Prognostic significance of nm23-H1 expression in oral squamous cell carcinoma

Recent studies indicated nm23-H1 played a role in cancer progression. Therefore, we investigated clinical significance of nm23-H1 expression in oral squamous cell carcinoma (OSCC). In total, 86 OSCC specimens were immunohistochemically stained with nm23-H1-specific monoclonal antibodies. Immunohistochemical staining of nm23-H1 was confirmed by immunoblotting. The relations between nm23-H1 expression and clinicopathologic variables were evaluated by chi(2) analysis. As increased size of primary tumour could escalate metastatic potential and the data of patients at the late T stage might confound statistical analyses, we thus paid special attention to 54 patients at the early T stage of OSCC. Statistical difference of survival was compared by a log-rank test. Immunohistochemically, nm23-H1 expression was detected in 48.8% (42 out of 86) of tumorous specimens. It positively correlated with larger primary tumour size (P=0.03) and inversely with cigarette-smoking habit (P=0.042). In patients at the early T stage, decreased nm23 expression was associated with increased incidence of lymph node metastasis (P=0.004) and indicated poor survival (P=0.014). Tumour nm23-H1 expression is a prognostic factor for predicting better survival in OSCC patients at the early T stage, which may reflect antimetastatic potential of nm23. Therefore, modulation of nm23-H1 expression in cancer cells can provide a novel possibility of improving therapeutic strategy at this stage. In addition, our results further indicated cigarette smoking could aggravate the extent of nm23-H1 expression and possibly disease progression of OSCC patients.

Anaplastic transformation of thyroid cancer: review of clinical, pathologic, and molecular evidence provides new insights into disease biology and future therapy

BACKGROUND

Anaplastic thyroid cancer ranks among the most lethal of all human malignancies. Its rarity and rapidly fatal course have made it a difficult cancer to both study and treat. Unfortunately, there has been little progress in the management and control of this malignancy. Anaplastic transformation, or the intratumoral evolution of anaplastic carcinoma from pre-existing differentiated thyroid cancer, has become a well-accepted process, despite a limited understanding of its underlying mechanisms.

METHODS

It is through review of the literature that an understanding of the aggressive disease biology can be developed. The aim of this review is to evaluate the relevant clinical, pathologic, and molecular studies to develop an insight into the mechanisms that underlie the intratumoral molecular evolution of anaplastic thyroid carcinoma.

RESULTS/CONCLUSION

It is based on an understanding of this process that effective treatments for this aggressive malignancy are currently being developed.

Nm23-H1 immunohistochemical expression in multisteps of cervical carcinogenesis

To evaluate the expression of nm23-H1 protein in normal, precancerous, and cancerous tissues of the uterine cervix and its role in cervical carcinogenesis, metastasis and recurrence, 82 cervical specimens, including 30 squamous cell carcinomas (SCC), 19 high- and 13 low-grade squamous intraepithelial lesions (HSILs and LSILs) and 20 normal samples, were stained using immunohistochemical method with streptavidin-biotin peroxidase immunostaining. The Chi-square and Fisher's exact tests, as well as Chi-square test for trend, were used for comparing nm23-H1 expression among normal, LSIL, HSIL, and cancerous tissues. The correlation of nm23 expression with metastasis or recurrence was analyzed using Fisher's exact test. There were significant differences in levels of nm23-H1 expression between LSIL and HSIL (P = 0.016) and between LSIL and SCC (P = 0.004), but not between HSIL and SCC or normal and LSIL samples. Furthermore, a positive relationship was demonstrated for high nm23-H1 protein expression and degree of malignant transformation (P < 0.05). Among the 30 SCC cases, high nm23-H1 expression did not show significant association with either carcinomatous metastasis or recurrence (P = 0.123, 0.372, respectively). High nm23-H1 expression appears related to critical progression of LSIL to HSIL but not to metastasis or recurrence of SCC.

Anaplastic thyroid cancer

Anaplastic thyroid carcinoma is one of the most aggressive malignancies, with a poor prognosis. Although rare, representing only 2% of clinically recognized thyroid cancers, the overall median survival is limited to months. Most patients are elderly and seek treatment with a rapidly growing mass. Almost half the patients seek treatment with distant metastases, with as many as 75% developing distant disease during their illness. In most the patients, complete surgical resection is not possible. There are, however, a few patients with resectable disease reported in the literature who have demonstrated long-term survival with aggressive multimodal therapy that included surgery, radiation, and chemotherapy. Preclinical studies in human anaplastic thyroid carcinoma cell lines show promise that new approaches to the management of this disease will be found in the future. Until such time when an effective regimen is found, all patients with anaplastic thyroid carcinoma should be evaluated for multimodal therapy in the setting of a clinical trial.

Prognostic implication of nm23-H1 expression in colorectal carcinomas

AIMS

Expression of nm23 has been identified as a potential metastatic suppressor. In this study, nm23-H1 expression, clinicopathological parameters and influences on clinical outcomes were investigated in colorectal carcinoma patients.

METHODS

Immunostaining was performed on 185 colorectal carcinomas using a polyclonal anti-nm23-H1 antibody.

RESULTS

The nm23-H1 immunoreactivity was weak in 31 (17%), moderate in 48 (26%) and strong in 106 (57%) cases. The well differentiated adenocarcinomas showed significantly strong staining for nm23-H1 compared with the moderately and poorly differentiated adenocarcinomas (chi2 test, P<0.001). Advanced tumour stages were associated with reduced nm23-H1 expression (P<0.001). There was an inverse correlation with angiolymphatic invasion, nodal metastasis and liver metastasis (univariate logistic regression analysis, P<0.001). In univariate analysis, patients with reduced expression of nm23-H1 had significantly shorter overall and disease-free survival than the strong expression group (log-rank test for trend, P=0.002 and P=0.003, respectively).

CONCLUSIONS

Our results indicated that reduced nm23-H1 expression showed poor prognosis in colorectal carcinomas. As a result, nm23-H1 expression might be a useful marker to predict outcome while planning treatment.

Cancer-specific mRNAs in thyroid carcinomas: detection, use, and their implication in thyroid carcinogenesis

Molecular-based diagnosis ofthyroid carcinomas can be more easily establishedby utilizing specific mRNAs that are expressed in a restricted manner in cancer tissues. Accordingly, several cancer-specific mRNAs in thyroid carcinomas have been identified by means of sequence specific-differential display (SS-DD), serial analysis of gene expression (SAGE) and other new techniques. By using these cancer-specific mRNAs, some new methods of preoperative diagnosis of thyroid carcinomas have been developed. In one such method, Aspiration Biopsy-Reverse Transcription-Polymerase Chain Reaction (ABRP), RNA is extracted from leftover cells within the needle used for fine needle aspiration biopsies (FNABs), thereby allowing cytological and molecular-based diagnoses to be performed simultaneously. ABRP provides both RNA information and a cytological diagnosis without further invasion to the patient. By ABRP detection of cancer-specific mRNAs, papillary, anaplastic and medullary carcinomas and a part of malignant lymphomas can be accurately diagnosed preoperatively. It remains to be clarified why cancer-specific mRNAs, especially those that are overexpressed in fetal tissues, can clearly distinguish benign tissues from carcinomas, while genomic alternations, such as mutations in the RAS or P53 gene cannot. Further, the widely accepted hypothesis of multi-step carcinogenesis cannot explain some of the clinical and experimental findings of thyroid carcinomas. Considering these facts, we propose a novel hypothesis of thyroid carcinogenesis, the "germ-cell carcinogenesis" hypothesis, in which cancer cells derive from the remnants of fetal thyroid germ cells (thyroblasts) instead of normal thyroid follicular cells.

Expression of p16, nm23-H1, E-cadherin, and CD44 gene products and their significance in nasopharyngeal carcinoma

OBJECTIVE

The present study was aimed to determine whether p16/MTS1, nm23-H1, E-cadherin, and CD44 proteins were expressed in nasopharyngeal carcinoma (NPC) and whether those expressions were pathologically significant in the progress of NPC.

METHOD

We examined non-cancerous nasopharyngeal mucosa (20 cases) and NPC (80 cases) using immunohistochemistry with six different types of monoclonal antibodies against p16, nm23-H1, E-cadherin, CD44H, CD44v3, and CD44v6 proteins.

RESULTS

The results showed that 1) the rates of positive p16 protein expression and of preserved E-cadherin protein expression in NPC were significantly lower than those in non-cancerous tissue (P <.01); 2) no significant difference in the rate of positive expression of nm23-H1, CD44H, CD44v3, and CD44v6 proteins were observed between non-cancerous nasopharyngeal mucosa and NPC; 3) no significant difference in the expression of those proteins were found by respective correlation analyses of sex, stage, and size of primary tumor in NPC; and 4) no significant difference in the rates of positive expression of CD44H, CD44v3, and CD44v6 proteins were observed in NPC between with and without lymph node metastasis, indicating that those gene products did not correlate with lymph node metastasis in NPC. However, there were inverse correlations between the expression of p16, nm23-H1, or E-cadherin protein and lymph node metastasis (P <.05), indicating that the expression of p16, nm23-H1, and E-cadherin gene were related to the carcinogenesis and tumor progression of NPC.

CONCLUSION

Detecting the expressions of those gene products may provide clinically valuable information for therapeutic strategy and for predicting the prognosis of patients with NPC.

Comparison of histological changes and changes in nm23 and c-MET expression between primary and metastatic sites in osteosarcoma: a clinicopathologic and immunohistochemical study

Changes in morphological features between the primary and metastatic sites in osteosarcoma and the role of nm23 protein and c-MET oncogene product have remained controversial. In addition to histological studies, we evaluated the expression of nm23, c-MET, p53, and MDM2 immunohistochemically using 25 osteosarcomas in which both primary and concordant metastatic specimens were available. Moreover, we assessed proliferative activity using the monoclonal antibody MIB-1. Among these 25 cases, 4 tumors that were osteoblastic type (16%) in the primary site had changed morphologically to MFH-like type in the metastatic site, whereas 2 MFH-like type and 1 small cell-type tumors had changed to osteoblastic type. MIB-1 LI was significantly higher in the metastatic site than in the primary site (primary, 20.02; metastatic, 26.72; P = .0209). Seventeen cases (68%) showed increased nm23 expression in the metastatic site, whereas 2 cases showed reduced expression. nm23 expression was significantly increased in the metastatic site, compared with the primary site (P = .0009). Seven cases (28%) showing negative reaction for c-MET in the primary site showed immunuoreactivity for c-MET in the metastatic site. Although there was no statistical significance, c-MET expression seemed to be more frequent in the metastatic site, compared with the primary site. Among the overall tumors, c-MET-positive tumors showed significantly higher MIB-1 LI, compared with c-MET-negative tumors (negative, 20.99; positive, 27.65; P = .0292). No significant change was observed regarding p53 and MDM2 between the primary and metastatic site. Our results suggest that rather than being a metastasis-suppressor gene, nm23 is in fact correlated with metastatic progression in osteosarcoma. Positive correlation between c-MET expression and proliferative activity also suggests that c-MET expression may play an important role in tumor progression in osteosarcomas.

FHIT gene abnormalities in both benign and malignant thyroid tumours

FHIT, a candidate tumour suppressor gene, has recently been identified at chromosomal region 3p14.2, and deletions of the gene have been reported in many types of human cancers. Loss of heterozygosity (LOH) at this region has also been found frequently in follicular thyroid carcinoma (FTC). To investigate the potential role of FHIT in thyroid tumorigenesis, we examined 57 thyroid tumour specimens (eight benign adenomas, 40 papillary, four follicular and five anaplastic carcinomas), and two thyroid carcinoma cell lines (NPA, SW579) for genetic alterations by using reverse transcription-polymerase chain reaction (RT-PCR), PCR product sequencing, single-strand conformation polymorphism (SSCP) and Southern blot analysis. Two cervical carcinoma cell lines (C-33A, HeLa) were included as positive controls. We detected truncated FHIT transcripts in three of eight (38%) benign adenomas, nine of 40 (23%) papillary, and two of five (40%) anaplastic carcinomas, and in three cell lines (SW579, C-33A, HeLa). Most of the truncated transcripts lacked exons 4 or 5 to 7 or 8 of the gene and were presumably non-functional as the translation start site is located in exon 5. SSCP analysis of the coding exons failed to detect any point mutations among the samples without abnormal FHIT transcripts. Southern blot analysis demonstrated either loss or reduced intensity of major Bam HI restriction fragments in the three cell lines found to have abnormal FHIT transcripts, indicating, respectively, either intragenic homozygous or heterozygous deletions of the FHIT gene. Intragenic homozygous deletions were also found in two papillary thyroid carcinoma specimens: one was missing a 13 kb Bam HI fragment which contains exon 4, the other had deletions of 15.5, 13 and 4.2 kb fragments which contain exons 2 and 9, 4, and 5, respectively. The absence of a defective FHIT gene in FTC indicates that an additional tumour suppressor gene may reside in this region and be involved in the development of FTC. Given that defective FHIT genes were found in both benign and malignant thyroid tumours, the inactivation of this putative tumour suppressor gene is likely to be an early event in the pathogenesis of some forms of thyroid neoplasms.

Anaplastic thyroid carcinoma: a therapeutic challenge

Anaplastic thyroid carcinoma is an extremely aggressive solid tumor that resists most therapeutic efforts and is almost always fatal. It typically arises as a terminal dedifferentiation of unrecognized long-standing differentiated thyroid carcinoma. Current chemotherapeutic agents are not capable of consistent beneficial therapeutic responses, although rare patients may gain additional months of survival. Aggressive local tumor control with surgery and external beam radiotherapy may provide palliation and delay eventual death from distant metastatic disease. This disease challenges clinicians and researchers to develop new systemic therapies as well as to aggressively treat differentiated thyroid cancers before they become anaplastic tumors.

Expression of nm23 in gastric carcinoma: association with tumor progression and poor prognosis

BACKGROUND

Expression of nm23 has been shown to be inversely correlated with the metastatic potential of several human cancers. In the current study, the expression and prognostic impact of nm23 was immunohistochemically studied in 413 curatively resected gastric carcinomas.

METHODS

Tumor sections of the 413 gastric carcinomas were stained with a polyclonal antibody that was raised against the nm23-H1/NDP kinase A, which is identical to the nm23-H1 gene product.

RESULTS

Expression of nm23 was detected in 84.5% (n = 349) of all tumors, in the majority of cases (71.2%) causing a homogeneous staining reaction in more than 75% of tumor cells. Expression of nm23 was positively correlated with the intestinal type of tumor, according to the Lauren classification and advanced pT categories, and was also correlated with the presence of blood and lymphatic vessel invasion. In contrast, no correlation could be demonstrated between nm23 expression and lymph node involvement. As shown in univariate analysis, patients with nm23 positive tumors, especially those with nm23 positive diffuse-type carcinomas, had significantly shorter overall survival than patients with nm23 negative tumors (P = 0.03 and P = 0.0065, respectively). However, in a multivariate analysis that included the prognostic parameters pT category, pN category, and blood and lymphatic vessel invasion, this prognostic impact was not maintained.

CONCLUSIONS

In contrast to results for breast and colorectal carcinomas, our results for 413 gastric carcinomas showed that expression of the designated metastasis suppressor gene nm23 is correlated with aggressive tumor growth and poor prognosis but is not an independent prognostic marker.

Inhibition of colonization and cell-matrix adhesion after nm23-H1 transfection of human prostate carcinoma cells

A human gene, nm23-H1, has been known as a metastasis suppressor in many tumor cells. The cellular mechanisms by which the nm23-H1 protein may directly or indirectly modulate the metastatic phenotype are not yet known. In this study the phenotypic effect of transfection of nm23-H1 cDNA into the human DU 145 prostate carcinoma cell line was examined. Despite similar growth rates, the nm23-H1-transfected lines displayed decreased colonization in soft agar and adhesion to extracellular matrix components when compared with the control transfected line. The results suggest that the nm23-H1 gene product suppresses the metastatic potential of prostate carcinoma cells by inhibiting their ability in anchorage-independent growth and extracellular matrix adhesion.

Anaplastic thyroid carcinoma: behavior, biology, and therapeutic approaches

Anaplastic thyroid carcinoma (ATC), although exceedingly rare, is the most aggressive solid tumor known. Early studies on the effects of different therapies may be biased by the inclusion of responsive "small cell" ATC patients, which are now known to be mostly lymphoma patients. Local control of disease with surgery and/or external beam radiotherapy (XRT) is of fundamental importance to enhance survival. Ultimately, nearly all ATC patients die from their disease, which is widely metastatic. Development of effective systemic chemotherapy agents would provide the best chance for long-term survival of patients. Early preliminary data suggest that paclitaxel may be helpful, although no agent has yet been identified to result in dramatic improvements in survival. Select patients may benefit from aggressive multimodal therapy, although it is important to provide appropriate palliative care when desired.

Evaluation of immunostaining for MIB1 and nm23 products in uterine cervical adenocarcinoma

In this study, we evaluated whether proliferative activity and metastatic potential are prognostic factors in adenocarcinoma of the cervix. Formalin-fixed, paraffin-embedded sections from 34 patients with cervical adenocarcinoma or adenosquamous carcinoma were immunostained with monoclonal antibody MIB1, expressed in proliferating cells, and anti-nm23 antibody, reacts with metastasis suppression gene products. MIB1 positivity ranged from 0.2 approximately 54.7% with a mean of 21.4%. The level did not differ significantly between various clinicopathological categories. Although patient survival of high or low MIB1 expressing tumor was not significantly different, the disease-free interval of high (> or =25%) expressing tumor was significantly lower than that of low (<25%) expressing tumor. Strong and medium expression for nm23 were detected in 7 (21%) and 3 (9%) of patients. Tumor with strong nm23 expression tended to have a higher relapse rate. Although the survival of strong and weakly nm23 expressing tumor was not significantly different, the disease-free survival of strong nm23 expressing tumor was lower than that of weakly nm23 expressing tumor. MIB1 and nm23 immunostaining might be some of prognostic indicators of recurrence in cervical adenocarcinoma. In cervical adenocarcinoma, the nm23 gene products may not function as metastatic suppression but reflect proliferative activity.

Prognostic significance of Nm23/NDPK expression in breast carcinoma, assessed on 10-year follow-up by automated and quantitative immunocytochemical assays

The Nm23 gene has been described as an antimetastatic gene; in some studies, disease progression in patients with solid tumours is related to Nm23 protein expression, which can be detected by immunohistochemical procedures. Detection of Nm23-H1 protein in breast cancer may be relevant for the monitoring of patient therapy, provided that the technical procedures are reliable and cost-effective. The aim of the present study was to determine the prognostic significance of Nm23, assessed by quantitative immunocytochemical assays (Nm23 ICAs), under optimal technical conditions. Nm23-H1 ICAs were performed on frozen sections, using an automated immunoperoxidase technique (Ventana) and computer-assisted analysis of digitized colour microscopic images (SAMBA), in a series of 168 breast carcinomas. The results of automated quantitative ICAs were correlated with patients' follow-up (129 months). Nm23-H1 immunocytochemical expression in histological sections of tumours in which more than 3 per cent of the surface area was positively stained was significantly (0.012) correlated with longer metastasis-free survival in both node-positive and node-negative groups of patients (P = 0.032 and P = 0.036, respectively) (Kaplan-Meier log-rank test, NCSS 6.0.1 software). Nm23 expression (cut-point 3 per cent) did not, however, correlate with overall survival, or with the recurrence-free survival. In multivariate analysis (proportional hazards regression, Cox model), the prognostic significance of Nm23 in terms of metastasis-free survival was independent of tumour size and grade, and of histological grade, in the entire cohort of patients. It is concluded that Nm23 immunodetection is only of limited practical clinical relevance in breast carcinoma, even when assessed under optimal technical conditions.

Expression of metastasis-associated genes h-mts1 (S100A4) and nm23 in carcinoma of breast is related to disease progression

The murine 18A2/mts1 and its human homolog h-mts1 (S100A4), encoding a Ca2+-binding protein belonging to the S-100 family, are associated with high invasive and metastatic potentials of murine tumors, human tumor cell lines in vitro, and human tumors growing as xenografts. The nm23 is a putative metastasis-suppressor gene whose expression has been found to correlate inversely with the metastatic potential of some forms of human cancer. The products of both human genes alter cytoskeletal dynamics, with antagonistic effects. In view of the equivocal association of nm23 with the metastatic potential of human cancer, we suspected that the relative expression of h-mts1 and nm23 might reflect tumor progression more accurately than either of them alone. We describe here the expression of these genes in infiltrating ductal carcinomas of the breast and show that high h-mts1 expression is associated with metastatic spread to the regional lymph nodes. The expression of nm23 on its own did not show a statistically significant inverse correlation with nodal spread. However, the expression status of the two genes, taken together, correlated strongly with the occurrence of nodal metastases. Breast cancers with no detectable expression of h-mts1 were found to be estrogen and progesterone receptor positive. Expression of h-mts1 was not related to tumor differentiation. The clinical data, together with the state of expression of steroid receptors and the expression levels of h-mts1 and nm23 genes, were analyzed using artificial neural networks for accuracy in predicting nodal spread of the carcinomas. These analyses support the conclusion that, overall, h-mts1 expression appears to be associated with and indicative of more aggressive disease. Complemented with nm23, h-mts1 could provide a powerful marker of breast cancer prognosis.

Nm23 gene expression in gastric carcinoma: an immunohistochemical study

BACKGROUND

The gene Nm23 is thought to play a role in the suppression of tumour metastasis. Reduced expression of Nm23 is seen in a number of human cancers, and is associated with increased metastasis and reduced survival, most strongly in ductal breast and colorectal carcinomas.

METHODS

Nm23 gene expression was compared in gastric carcinoma and normal gastric mucosa. Twenty-three gastric carcinomas were graded for differentiation as either well, moderately or poorly differentiated. Metastatic deposits from seven of the cases were also examined, along with 10 samples of normal gastric mucosa. Specimens were incubated with a murine monoclonal antibody against the protein product of Nm23, and examined by immunohistochemical staining. A semiquantitative immunostaining index was used.

RESULTS

All normal mucosa showed moderate to strong staining; 8 of 15 poorly differentiated carcinomas showed absent or weak staining; 1 of 6 moderately differentiated carcinomas stained weakly. Both well-differentiated carcinomas stained strongly; 1 of 7 metastatic deposits stained weakly. The difference in Nm23 expression between normal mucosa and carcinomas was statistically significant (P=0.024). However, there was no statistically significant difference between the three grades of carcinomas (P=0.51), or between primary and metastatic tumour (P=0.25, all by Chi-squared test).

CONCLUSIONS

These results suggest that Nm23 may have a role in gastric carcinoma pathogenesis, but do not show a correlation with metastasis. A larger study, involving detailed clinical staging and follow-up, may be of benefit.

Phenotypic analysis of ovarian carcinoma: polypeptide expression in benign, borderline and malignant tumors

Studies of multiple markers in tumors are required for adequate biological characterization. We have characterized the expression of multiple proteins in human ovarian tumors using the technique of 2-dimensional gel electrophoresis (2-DE/PDQUEST). Tumor cells were prepared from the tissue of 22 ovarian tumors. Large variations were observed between tumors in the expression of various polypeptides, indicating heterogeneity in gene expression. An increase in the spot density of 2 cell-cycle-related proteins, PCNA and OP18/stathmin, was observed in carcinomas. Borderline tumors expressed low levels of these proteins. Significant increases in the levels of nm23, GST-pi, elongation factor 2 and triose phosphate isomerase were recorded in ovarian carcinomas. Furthermore, decreases in the levels of tropomyosin-2 and lamin C were observed in malignant as compared with benign tumors. The pattern of expression of 9 protein markers was examined in individual tumors. All malignant tumors showed simultaneous alterations in the expression of 5 or more of these proteins, whereas no benign tumor showed alterations in the expression of more than 3 polypeptides. Borderline tumors showed alterations in 0 to 6 markers. We conclude that the simultaneous analysis of multiple polypeptides, which can be achieved by 2-DE, is useful for characterization of gene expression and diagnostic studies in ovarian tumors.

Two-dimensional separations of the genome and proteome of neuroblastoma cells

Two-dimensional (2-D) electrophoretic methods have been available that allow separation of the protein constituents of a cell population. It has also become feasible to electrophoretically separate in two dimensions and to display DNA fragments derived from genomic digests. Through the appropriate choice of restriction enzymes, the functional component of the genome that encompasses CpG islands can be preferentially visualized in 2-D gels. The same computerized approach for the analysis of 2-D patterns can be applied to investigations at either the protein or DNA levels. Our group has utilized 2-D electrophoresis to investigate both protein and DNA changes in cancer. The emphasis to date has been on the identification of proteins, the abundance of which is related to specific biological features of the tumors analyzed and of DNA fragments encompassed in genomic amplifications, as the latter commonly contain growth-related genes. Findings derived from our analysis of neuroblastoma tumors and cell lines using 2-D approaches are reviewed. Data for four proteins observed in 2-D gels are presented because of our demonstrated association of these proteins with differentiation and proliferation properties of neuroblastoma. At the genomic level, the detection of amplifications using 2-D gels has necessitated an understanding of the variability displayed by multi-copy genomic fragments, which we have accomplished to a large part and which we present. An important benefit of 2-D approaches is the efficiency of scale and the ease with which abundant proteins or multicopy genomic fragments can be detected, identified and quantitatively analyzed.

Evidence of gene deletion of p21 (WAF1/CIP1), a cyclin-dependent protein kinase inhibitor, in thyroid carcinomas

Eukaryotic cell cycle progression is controlled by a host of cyclin/cyclin-dependent kinases (Cdks), that are themselves regulated by multiple factors, including a group of small cyclin-Cdk inhibitor proteins (p15, p16, p21 and p27). The involvement of Cdk inhibitors in carcinogenesis has been demonstrated by the studies of p16. p53 is frequently mutated in thyroid carcinomas and p21/Waf1 is a downstream effector of p53. It is conceivable that genetic defects of genes downstream in the p53 pathway could also be oncogenic. We, therefore, examined a series of 57 thyroid tumour specimens (eight follicular adenomas and 49 carcinomas) for deletion and point mutation of the p21/Waf1 gene. Three different kinds of deletions ranging from 349 to 450 bp were detected in five papillary carcinoma specimens by reverse transcription-polymerase chain reaction (RT-PCR). All the deletions were involved in the second exon of the p21/Waf1 gene. RT-PCR single strand conformational polymorphism (SSCP) analysis of remaining samples failed to reveal any point mutations in the coding region of the gene, except for a polymorphism at codon 31 (Ser to Arg). Genomic Southern blot analysis did not demonstrate any gene deletion or rearrangement in these samples, indicating abnormal RNA splicing may be involved. Analysis of intron-exon boundary and the coding region of the second exon did not reveal any mutation except for a point mutation (C to G) located 16 bp downstream from the splice donor site of the second intron in three out of five samples with p21/Waf1 deletions. Whether the mutation plays any role in aberrant RNA splicing remains to be determined. Among the five samples with p21/Waf1 gene deletions, none of them simultaneously carried a p53 or retinoblastoma (Rb) gene mutation. No p21/Waf1 abnormality was found in the benign adenomas. Thus, 12.5% (5/40) of thyroid papillary carcinoma specimens harboured p21/Waf1 gene deletions. Our data suggest that p21/Waf1 gene deletion is involved in thyroid carcinogenesis and may play an important role in thyroid cell transformation.

Gene usage and regulation of Gsα gene expression in thyroid cells

The TSH receptor is a G-protein-coupled seven transmembrane segment receptor. The interaction between TSH and its receptor mediates signal transduction by activating adenylyl cyclase through Gsα. There are four forms of Gsα (two short [45 kDa] and two large [52 kDa]), arising from alternative splicing of exon 3 of the Gsα gene. Gsα-1 and -2 contain exon 3, whereas exon 3 is spliced out in Gsα-3 and -4. The inclusion of a serine residue at the 3' splice junction of exon 3 distinguishes Gsα-2 and -4 from Gsα-1 and -3. The expression of different Gsα forms appears to be tissue-specific. In this study, we have examined the Gsα splice variants in 26 human thyroid tumor specimens and rat thyroid tissues as well as a rat FRTL-5 cell line. Furthermore, we have studied the regulation of the Gsα gene expression by TSH and cAMP in FRTL-5 cells. We found that Gsα-1 and -4 mRNA were present in both human and rat thyroid cells, although Gsα-4 was more abundant in human thyroid cells as compared to rat thyroid and FRTL-5 cells. The Gsα mRNA can be easily amplified by RT-PCR regardless of tumor type and stage, suggesting that Gsα gene expression in thyroid tumors may not be markedly affected by dedifferentiation of thyroid cells.Both TSH and 8-bromo-cAMP, a cAMP analog, can stimulate the Gsα gene expression in FRTL-5 cells with maximal effect by 6 h and 1 h, respectively. The addition of cycloheximide to the culture of FRTL-5 cells abolished the effect of bTSH, but not that of 8-bromo-cAMP, on the expression of the Gsα gene. Cellular cAMP measurements showed that bTSH-stimulated cAMP production was significantly reduced to the basal level after addition of cycloheximide. These results suggest that regulation of the Gsα gene expression by TSH is mediated by a cAMP-dependent process and requires new protein synthesis.

Evaluation of the prognostic significance of nm23/NDP kinase and cathepsin D in anal carcinomas. An immunohistochemical study

Reduced expression of nm23/NDP kinase and increased expression of cathepsin D seem to be correlated with a high metastatic potential for a variety of malignancies. Nm23/NDP kinase and cathepsin D have been correlated with several clinical variables, including survival in 96 patients with squamous cell carcinoma of the anal canal. Immunohistochemical methods were used on paraffin-embedded biopsies. Seventy-six (79%) anal carcinomas were nm23/NDP kinase positive, whereas 35 (36%) and 28 (29%) of the cases were cathepsin D positive in tumor cells and stromal cells, respectively. We have found no indication that the extent of cathepsin D staining has any prognostic significance. The overall survival of patients with tumours positive for nm23/NDP kinase in the cytoplasm was significantly shorter than that of patients with anal carcinomas negative for nm23/NDP kinase.

Immunohistochemical detection of nm23/NDP kinase and cathepsin D in medullary carcinomas of the thyroid gland

Reduced expression of nm23/NDP kinase and increased expression of cathepsin D seem to be correlated with the high metastatic potential in a variety of malignancies. The expression of nm23/NDP kinase and that of cathepsin D have been evaluated by means of an immunohistochemical technique in paraffin-embedded tissues from 44 primary medullary carcinomas of the thyroid gland (MCT) and from the corresponding lymph node metastases in 32 of these cases. In addition, lymph node metastases from 4 cases were studied. We found that 36 of 44 (82%) primary and 26 of 36 (72%) lymph node metastatic MCT were nm23/NDP kinase positive, whereas 14 of the 44 (32%) primary and 17 of the 36 (47%) lymph node metastatic MCT were cathepsin D positive. We found no indication that the nm23/NDP kinase level has any prognostic significance in MCT. The cathepsin D level is close to being prognostically significant in this study, and we cannot exclude the possibility that it could be of prognostic value. However, it seems to be quite weak, and therefore of little use in a clinical situation.

The expression of the MDM2 gene, a p53 binding protein, in thyroid carcinogenesis

BACKGROUND

The authors previously found p53 mutations in 24% of malignant thyroid tumors, representing a wide stating spectrum. Overexpression of MDM2, most often due to gene amplification, has been suggested to be an additional mechanism for abrogation of the p53 function. In the current study, MDM2 gene expression and amplification were examined in a randomly selected subset of these tumors to explore the possibility that wild-type p53 may be inactivated by complexing with MDM2 in specimens without p53 mutations.

METHODS

MDM2 gene expression and amplification were studied by Northern and Southern blot analysis, respectively. Twenty-two thyroid tumors were included: 16 papillary carcinomas, 1 follicular carcinoma, 3 anaplastic carcinomas, and 2 multinodular goiters (adenomatous goiters).

RESULTS

A two- to threefold increase in MDM2 expression in 4 of 20 thyroid carcinomas was found. It was noteworthy that all of these four samples harbored p53 mutations. The association between increased MDM2 expression and p53 mutation was statistically significant (P < 0.005). No evidence of MDM2 gene amplification or rearrangement accounting for such an increase in MDM2 expression was found.

CONCLUSIONS

Genetic and/or environmental factors contributing to random p53 mutations also may cause increased MDM2 expression. Given the moderate increase in MDM2 expression without associated genetic alterations such as gene amplification and rearrangement, MDM2 may not play any significant role in the development and progression of thyroid carcinoma.

Increased expression of the NME1 gene is associated with metastasis in epithelial ovarian cancer

The genetic events involved in the development of metastases of epithelial ovarian cancer are largely unknown. One gene postulated to play a role in tumour metastasis suppression is NME1 (nm23-H1), and an inverse relationship between NME1 expression and metastatic potential has been observed for some solid tumours. In this study we have investigated the levels of mRNA expression of the 2 isoforms of the NME gene, NME1 and NME2. A maximum of 45 tumours samples from 33 patients were available for Northern blot analysis. We observed variable levels expression of NME1 and NME2 mRNA. The average level of NME1, but not NME2, mRNA expression was statistically higher in metastatic biopsies when compared with primary tumour biopsies. To examine the possible tumour suppressor gene role of NME1 in ovarian tumours, 76 patients were investigated by Southern blot analysis to determine the rate of allelic deletion. Allele loss at 5 other chromosome 17 loci (D17S5, TP53, NF1, D17S74, D17S4) was also evaluated for many of these 76 patients. Allele loss was observed in 22/30 (73%) informative patients at the NME1 locus. We also observed high rates of allele loss at the other loci evaluated. No correlations with clinical stage, histological subtype or patient survival were observed in either mRNA or DNA analyses. We have established that tumour progression in ovarian cancer is accompanied by over-expression of the NME1 gene; however, despite high rates of allele loss at the NME1 locus, the concept that NME1 may be a candidate tumour suppressor gene in ovarian cancer cannot be confirmed by this study.