Expression of the nm23 homologues nm23-H4, nm23-H6, and nm23-H7 in human gastric and colon cancer

Eight members of the nm23-gene family have been described. The involvement of nm23-H1 and nm23-H2 in tumour progression and metastasis, as well as in gene regulation and apoptosis, has been shown in numerous studies. Whether nm23-H4, -H6, and -H7 play a role in tumours is, however, largely unknown. This study describes data on the expression of these three nm23 homologues in human colon and gastric cancer by real-time RT-PCR and immunohistochemistry. Increased expression of these genes, most strikingly nm23-H4 and -H7, was observed in the majority of tumours analysed. No correlation with tumour stage according to the TNM classification was found. In contrast, by immunohistochemical analysis, nm23-H4 and -H6 overexpression correlated with the intestinal tumour type in gastric cancer tissues, whereas no increased immunoreactivity for the three nm23 proteins was noted in the diffuse type tumour specimens. These findings indicate that nm23-H6, and particularly nm23-H4 and -H7, may be involved in the development of colon and gastric carcinoma, the latter possibly in a type-specific manner. A contribution to tumour progression or metastasis could not, however, be proven. Elucidation of the specific mechanisms by which the nm23 homologues nm23-H4, -H6, and -H7 are involved in tumour development requires further studies.     

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.     

环孢素A对人滋养细胞nm23-H1表达的调控作用

目的:探讨环孢素A（CsA）对人滋养细胞系Bewo的23号非转移性基因（nometastatic gene23）H1型即nm23-H1表达的调控作用，为治疗滋养细胞疾病提供新的依据。方法:将Bewo细胞分为对照组（加溶媒）、环孢素组加入终浓度由10-2 μmol/L-10 μmol/L环孢素A。分别于48 h后用RT-PCR检测nm23-H1基因mRNA表达水平，于72 h后用In cell Western分析nm23-H1蛋白表达水平。结果:与对照组相比，nm23-H1的表达水平随环孢素A浓度10-2 μmol/L-1 μmol/L呈现降低趋势，其中1.0 μmol/L环孢素A nm23-H1 mRNA和蛋白水平均明显降低（P＜0.05， P＜0.01）；当浓度升高至10 μmol/L时，nm23-H1则呈升高趋势。结论:低浓度环孢素A可通过降调节nm23-H1的表达，继而改善滋养细胞的侵袭力。     

乳腺癌中nm23-H1 mRNA及其蛋白低表达的研究

目的 探讨ｎｍ２３－Ｈ１ ｍＲＮＡ及其蛋白低表达之间相关性及与乳腺癌生物学行为的关系。方法 应用ＲＴ／ＰＣＲ及免疫组化方法对５８例乳腺癌组织中ｎｍ２３－Ｈ１ ｍＲＮＡ及其蛋白的表达进行检测。结果 分别有４４．８％,４８．２％的乳腺癌伴有ｎｍ２３－Ｈ１ ｍＲＮＡ或该基因编码蛋白的低表达,ｎｍ２３－Ｈ１ ｍＲＮＡ与其蛋白表达虽有相关性,但并不完全吻合。     

子宫内膜异位症中nm23-H1基因表达的意义

目的：探讨nm23-H1基因在子宫内膜异位症发生中的作用。方法：采用免疫组织化学SP法检测25例子宫内膜异位症和22例正常子宫内膜组织中nm23-H1的蛋白表达情况；采用RT-PCR检测研究33例子宫内膜异位症的异位子宫内膜组织和30例正常子宫内膜组织中nm23-H1基因的mRNA表达情况。 结果：25例子宫内膜异位症组中，nm23-H1的蛋白表达缺失为3例、弱阳性12例、强阳性10例，对照组中nm23-H1的蛋白表达缺失为0例、弱阳性3例、强阳性19例，两组差异显著（P<0.01）。33例子宫内膜异位症组中nm23-H1 mRNA表达缺失为4例、弱表达15例、强表达14例，30例对照组中，nm23-H1的mRNA表达缺失为1例、弱表达6例、强表达23例，子宫内膜异位症组明显低于正常对照组（P<0.05）。 结论：nm23-H1在子宫内膜异位症的发病过程中可能起重要的作用，进一步明确nm23-H1基因在子宫内膜异位症发生中的作用及其作用机制，对了解子宫内膜异位症的发病机制、临床诊断和治疗可能有一定意义。     

nm23-H1 protein expression and gene mutation in 150 patients with non-Hodgkin's lymphomas

The metastasis-suppressing role of the nm23 gene in the metastatic spread of malignant tumor is still debated. We examined the nm23-H1 protein expression and gene mutation in non-Hodgkin's lymphomas to compare with the clinicopathologic parameters. The expression of nm23-H1 protein was immunohistochemically examined in 150 cases of non-Hodgkin's lymphomas; 85 diffuse large B cell lymphomas (DL-BCL), 18 marginal zone B cell lymphomas (MZL), 3 mantle cell lymphomas, 25 peripheral T cell lymphomas, not otherwise specified (TCLNOS), and 19 NK/T cell lymphomas (NK/T). Eighty-one cases (58 DLBCL, 6 MZL, 4 TCLNOS, and 13 NK/T) were studied for nm23-H1 gene mutation in exon 1 to 5. The high expression of nm23-H1 protein was associated with the high IPI score (p=0.019) and the low survival rate of the patients (p=0.0039). The gene mutation of nm23-H1 was detected in 10.3% of DLBCL and 30.7% of NK/T; but none in MZL and TCLNOS. The mutation was found in exon 1 in 5 cases, exon 2 in two cases, exon 4 in one case and both exon 1 and 2 in two cases. Our results suggest that the expression of nm23-H1 protein can be used as a poor prognostic marker in non-Hodgkin's lymphomas, and the mutational change of gene may operate in the lymphomagenesis.     

Association between nm23-H1 expression, proliferation and apoptosis in non-small cell lung carcinomas

Twelve non-small cell lung carcinomas and adjacent normal lung tissues were examined for mutations of the nm23-H1 gene by using SSCP analysis and for an expression of the nm23-H1 protein by immunohis-tochemistry. No mutations could be found in either the carcinomas or in the adjacent normal tissues. In contrast, six of 12 carcinomas showed protein expression while only one adjacent normal lung tissue yielded a positive staining result. Therefore, the expression of nm23-H1 protein was analysed in a larger group of non-small cell lung carcinomas (n = 185) to determine whether or not the expression of nm23 protein may be of prognostic relevance. Only a weak relationship between nm23-H1 expression and lymph node involve-ment was observed. However, a significant correlation between proliferation and nm23-H1 expression was detected. Additionally, a direct correlation between apoptosis and nm23-H1 expression or between myc and nm23-H1 expression was found. Finally, non-small cell lung carcinomas that expressed nm23-H1 protein were more frequently sensitive to doxorubicin than carcinomas that did not express this protein. ©Lippincott Williams & Wilkins     

肝细胞癌nm23－H1蛋白表达的研究

应用免疫组化检测８８例肝细胞癌（ＨＣＣ）中ｎｍ２３－Ｈ１蛋白的表达。癌旁肝组织强阳性表达，５１例肝癌组织阳性表达（５８％）。阳性产物主要定位于肿瘤细胞胞浆。ｎｍ２３－Ｈ１蛋白表达与ＨＣＣ肿瘤体积，组织分型及Ｅｄｍｏｎｄｓｏｎ分级无关，而与肝内或肝外转移显著负相关。结果表明ｎｍ２３－Ｈ１在抑制ＨＣＣ肝内或肝外转移中起着重要作用，有可能成为评价ＨＣＣ病人预后的一项新指标。     

nm23—H1过表达与乳腺癌和皮肤癌转移的相关性

目的：对比研究乳腺癌与皮肤癌转移抑制基因ｎｍ２３－Ｈ１表达的意义。方法：用单克隆抗体免疫组织化学Ｓ－Ｐ法检测８１例乳腺癌及１００便皮肤癌。ｎｍ２３－Ｈ１阳性细胞数超过３０％的癌细胞定为过度表达。结果：乳腺癌中导管原位癌、无转移及有转移浸润性导管癌的过表达率分别为８２％、７７％和３３％。皮肤癌中基底细胞癌、无转移及有转移鳞状细胞癌的过表达率分别为７９％、６１％和２７％,判别有显著意义Ｐ〈０．００５％     

PCR-SSCP法检测人肝癌组织中nm23-H1基因突变的研究

目的观察nm23-H1基因在人原发性肝细胞癌中的突变情况，探讨nm23-H1基因突变与肝癌发生、发展度转移的关系。方法采用PCR-SSCP方法对16例肝癌组织、12例癌旁组织和4例正常肝组织的nm23-H1基因的第1、2、4外显子进行突变检测。结果共有5例发生nm23-H1基因突变。在1例癌旁组织中检测到nm23-H1基因第2外显子纯合缺失；在1例肝癌组织中第1外显子、1例第2外显子，癌旁组织中2例第2外显子检测到基因突变。结论nm23-H1基因突变在肝癌组织中发生率低，nm23-H1基因突变可能与肝癌进展度转移有关。     

Differential expression of the nm23 protein in the progression of oesophageal adenocarcinoma

AIM: Some studies have shown that abnormalities of the nm23 gene or its expression may be important in tumour dissemination, suggesting that the gene may have metastasis suppressing activity. This study set out to determine if nm23 protein expression is altered with progression and dissemination in oesophageal adenocarcinoma. METHODS: Paraffin-embedded, archival tissues of surgical resection specimens of oesophageal adenocarcinoma (n=46), some of which were accompanied by tissue from areas with high-grade dysplasia (n=24) and from metastasis in regional lymph nodes (n=16) were studied. Histologically normal oesophageal glandular tissue (of cardiac-type) (n=32) obtained from areas of the resections located away from the primary tumour masses and archival tissues of Barrett's metaplasia obtained from endoscopic biopsies (n=77) were used as non-neoplastic controls. Sections were immunohistochemically stained by the labelled streptavidin-biotin method using NCL-nm23 antibody. RESULTS: The total or overall amount of nm23 protein expression paralleled that of cytoplasmic expression and was increased in oesophageal adenocarcinomas (36/46 cases, 78%) when compared with normal oesophageal glandular epithelium (2/32, 6%), Barrett's metaplasia (8/77, 10%) and dysplasia (14/24, 58%). In metastatic carcinoma in regional lymph nodes, overall nm23 expression was similar in proportion (13/16, 81%) to that seen in primary carcinoma. In the analysis of the sequential development of oesophageal adenocarcinoma based on non-neoplastic, preneoplastic and neoplastic archival material, it was found that a high level of overall nm23 expression occurred firstly at the transition from Barrett's metaplasia (8/77, 10%) to dysplasia (14/24, 58%). Nuclear nm23 expression was low in dysplastic tissue (with none of the cases having a high level of nuclear nm23 expression) followed by increased levels as the lesion progressed to invasive adenocarcinoma (13/46, 28%) and metastatic carcinoma in regional lymph nodes (10/16, 63%). However, nm23 expression did not appear to correlate with sex, age, tumour size, extent of tumour infiltration into the oesophageal wall, presence of lymph node metastasis or overall patient survival. CONCLUSION: An overall increase in nm23 expression or increase in nm23 expression in the cytoplasm of cells may be important in the early development of oesophageal adenocarcinoma but increased levels of nuclear nm23 occur in its progression to metastatic disease.     

散发性胆囊癌nm23-H1基因遗传不稳定性与错配修复基因hMLH1和hMSH2蛋白表达的研究

目的:研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失,对nm23-H1蛋白表达的影响,同时检测错配修复基因hMLH1和hMSH2蛋白的表达,为揭示nm23-H1基因、hMLH1和hMSH2基因与肿瘤发生和转移机制提供实验依据.方法:采用石蜡包埋组织抽提DNA、PCR-SSCP、常规银染、Envision免疫组织化学等方法,对50例胆囊癌及其相应的正常组织,进行D17S396位点MSI、LOH的检测和nm23-H1、hMLH1和hMSH2蛋白表达研究.结果:①原发性胆囊癌D17S396位点遗传不稳定发生率为42.55%,LOH的发生率与肿瘤组织分化程度差异显著(P＜0.05);在肝脏侵润和淋巴转移组高于无肝脏侵润和无淋巴转移组(P＜0.01),在NevinⅣ+Ⅴ期高于Ⅰ+Ⅱ+Ⅲ期(P＜0.01);而MSI发生率则相反;②nm23-H1蛋白阳性率为46.81%,在淋巴转移组低于无淋巴转移组(P＜0.01);NevinⅣ+Ⅴ期低于Ⅰ+Ⅱ+Ⅲ期(P＜0.05);③hMLH1和hMSH2蛋白阳性率分别为51.06%和42.55%,hMLH1蛋白表达在有无淋巴转移组和Nevin分期有显著差异(P＜0.01),肝脏侵润组低于无肝脏侵润组(P＜0.05);④MSI阳性组中hMLH1蛋白阳性率显著高于MSI阴性组(P＜0.05).LOH阳性组中nm23-H1和hMSH2蛋白阳性率显著低于LOH阴性组(P＜0.05);⑤hMSH2蛋白阳性组中nm23-H1蛋白表达明显高于hMSH2蛋白阴性组(P＜0.05).结论:nm23-H1基因的遗传不稳定性可能是胆囊癌发生、发展的一个重要分子机制.nm23-H1基因的MSI和LOH,通过相互独立的途径调控胆囊癌的发生和转移.hMLH1/hMSH2表达异常可能是胆囊癌的早期分子事件.提高胆囊癌局部nm23-H1、hMLH1和hMSH2蛋白的表达,可减缓肿瘤的侵润转移并提高预后率.     

散发性胆囊癌nm23-H1基因遗传不稳定性与错配修复基因hMLH1和hMSH2蛋白表达的研究

目的： 研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失，对nm23-H1蛋白表达的影响，同时检测错配修复基因hMLH1和hMSH2蛋白的表达，为揭示nm23-H1基因、hMLH1和hMSH2基因与肿瘤发生和转移机制提供实验依据。方法: 采用石蜡包埋组织抽提DNA、PCR-SSCP、常规银染、Envision免疫组织化学等方法，对50例胆囊癌及其相应的正常组织，进行D17S396位点MSI、LOH的检测和nm23-H1、hMLH1和hMSH2蛋白表达研究。结果: ①原发性胆囊癌D17S396位点遗传不稳定发生率为42.55%，LOH的发生率与肿瘤组织分化程度差异显著（P <0.05）；在肝脏侵润和淋巴转移组高于无肝脏侵润和无淋巴转移组(P <0.01)，在NevinⅣ+Ⅴ期高于Ⅰ+Ⅱ+Ⅲ期(P <0.01)；而MSI发生率则相反；②nm23-H1蛋白阳性率为46.81%，在淋巴转移组低于无淋巴转移组(P <0.01)；NevinⅣ+Ⅴ期低于Ⅰ+Ⅱ+Ⅲ期(P <0.05)；③hMLH1和hMSH2蛋白阳性率分别为51.06%和42.55%，hMLH1蛋白表达在有无淋巴转移组和Nevin分期有显著差异(P <0.01)，肝脏侵润组低于无肝脏侵润组(P <0.05)；④MSI阳性组中hMLH1蛋白阳性率显著高于MSI阴性组(P <0.05)。LOH阳性组中nm23-H1和hMSH2蛋白阳性率显著低于LOH阴性组（P <0.05）；⑤hMSH2蛋白阳性组中nm23-H1蛋白表达明显高于hMSH2蛋白阴性组（P<0.05）。结论:nm23-H1基因的遗传不稳定性可能是胆囊癌发生、发展的一个重要分子机制。nm23-H1基因的MSI和LOH，通过相互独立的途径调控胆囊癌的发生和转移。hMLH1/hMSH2表达异常可能是胆囊癌的早期分子事件。提高胆囊癌局部nm23-H1、hMLH1和hMSH2蛋白的表达，可减缓肿瘤的侵润转移并提高预后率。     

乳腺癌组织中uPA、uPAR及nm23-H1的表达

目的　观察乳腺癌组织中uPA、uPAR、nm2 3 H1的表达并探讨与腋窝淋巴结转移的关系。方法　用免疫组化EnVi sion两步法检测 6 9例乳腺癌组织中uPA、uPAR和nm2 3 H1表达的分布情况 ,观察其与肿瘤的分化程度以及与腋窝淋巴结转移的关系。结果　 (1)uPA阳性表达定位于癌细胞胞质 ;uPAR和nm2 3 H1阳性表达定位于癌细胞胞膜及胞质 ,多数癌旁乳腺上皮细胞呈nm2 3 H1阳性表达 ;高分化乳腺癌 (Ⅰ级 )uPA和uPAR表达阳性率 (30 0 %和 2 5 0 %)低于中低分化乳腺癌 (Ⅱ、Ⅲ级 ) (分别为 6 8 1%、72 7%和 70 0 %、74 1%) (P <0 0 5 ) ;nm2 3 H1表达阳性率在乳腺癌组织不同分化程度间差异无显著性 (P >0 0 5 ) ;(2 )腋窝淋巴结有转移者uPA和uPAR的表达阳性率 (73 2 %和 75 6 %)高于无淋巴结转移者 (35 7%和35 7%) (P <0 0 5 ) ;有腋窝淋巴结转移者nm2 3 H1的表达阳性率 (2 4 4 %)显著低于无淋巴结转移者 (5 0 0 %) (P <0 0 5 ) ;uPA、uPAR和nm2 3 H1的表达与淋巴结转移的个数均无关 ;(3)uPA阳性表达的癌组织其nm2 3 H1表达阳性率 (15 0 %)低于uPA阴性表达的癌组织 (6 2 1%) (P <0 0 5 )。结论　uPA和uPAR的高表达与乳腺癌腋窝淋巴结转移密切相关 ;uPA、uPAR和nm2 3 H1可以作为乳腺癌侵袭与淋巴结转移的     

Semiquantitative immunoblot analysis of nm23-H1 and -H2 isoforms in adenocarcinomas of the lung: prognostic significance

Total amounts of nm23 protein and relative levels of H1 and H2 isoforms were studied in 27 fresh-frozen samples of pulmonary adenocarcinoma and adjacent non-neoplastic tissues that were obtained at surgery. Semiquantitative immunoblotting with a monoclonal antibody (Pan-242) against nm23 protein demonstrated both isoforms, recognized as 20.5 kDa for H1 and 18.5 kDa for H2, to be present in all cases. Both H1 and H2 levels in neoplastic tissues were higher than in the corresponding non-neoplastic samples. Expression of H2 was usually greater than of H1. The H2/H1 ratio varied from 1.9 to 14.1 (mean value 5.2) in non-neoplastic tissues and 1.0-5.9 (mean value 2.5) in neoplastic tissues, although this ratio did not correlate with any prognostic factor like tumor size, nodal status or distant metastasis (TNM tumor stage). H1 and H2 levels were significantly lower (mean values 4.3 and 2.4) in well-differentiated than in moderately and poorly differentiated adenocarcinomas (8.3 and 3.0) (P < 0.03 and P < 0.05, respectively). These data indicate that H1 and H2 isoform levels correlate with histological differentiation, but not the metastatic potential or stage of pulmonary adenocarcinoma.     

Squamous cell lung carcinomas: the role of nm23-H1 gene

 This analysis of 32 pairs of human squamous cell lung carcinomas and normal matched control DNA demonstrates that loss of heterozygosity (LOH) is infrequent at the nm23-H1 locus, affecting only 2 of the 18 informative cases. Both LOH cases were in the tumor stage IIIA. One tumor was of poor and the other of moderate histological grade. These and an additional 34 tumor samples were also analyzed immunohistochemically for the presence of nm23-H1 protein. Of the 66 cases tested for the presence of nm23-H1 protein 54 were negative. Eight samples exhibited up to 35% positive cells (with weak immunostaining intensity) and four between 35% and 70% (moderate immunostaining intensity); no sample showed more than 70% positive cells. Noncancerous lung parts contained no nm23-H1 protein. nm23-H1 expression was independent of TNM stage, grade, tumor size, and patient’s survival. Two samples with LOH were negative for nm23-H1 protein. We therefore conclude that neither loss of heterozygosity of the nm23-H1 gene nor the intensity of specific protein expression are related to squamous cell lung carcinoma development and progression. Received: 27 January 1997 / Accepted: 9 May 1997     

nm23-H1基因表达及突变与肝癌转移的关系

[摘要] 目的　研究nm23-H1基因的表达及突变和原发性肝细胞癌（hepatocellular carcinoma ,HCC）发展和转移的关系。方法 应用逆转录 PCR（RT-PCR）和逆转录PCR-单链构象多态法（RT-PCR SSCP）对30例肝癌组织、30例癌旁组织和4例正常肝组织中nm23-H1基因 mRNA表达和基因突变情况进行检测。 结果 nm23-H1基因在肝癌组织、癌旁组织、正常组织中的表达水平分别为1.62±0.41、1.30±0.30和1.23±0.39。肝癌组织中nm23-H1基因的表达水平明显高于癌旁组织（P<0.05）和正常组织（P<0.01）; 低分化肝癌组织中nm23-H1基因表达水平低于高、中分化肝癌组织中nm23-H1基因表达水平（P<0.05）;有卫星转移灶和无卫星灶的肝癌组织中nm23-H1基因表达水平无显著差异（P>0.05）;30例肝癌组织及相应的癌旁组织中未发现nm23-H1 cDNA基因突变。 结论 nm23-H1基因表达水平增高与肝癌的转移有密切关系,nm23-H1基因的异常表达是HCC转移中的频发事件而与基因突变无关。     

NM-23 gene loss of heterozygosity and protein expression in high-stage laryngeal squamous cell carcinomas.

Tumor suppressor genes that reduce metastatic potential have been described in a variety of different tumor types. One of the main tumor metastasis suppressor genes is nm-23, which is a nucleoside diphosphate kinase. Two isotypes, nm-23H1 and nm-23H2, have been cloned and map to chromosome 17q21.3. In a variety of tumors, including colon cancer and breast cancer, loss of expression of nm-23 is associated with lymph node metastasis. In other organ systems, however, this relationship is not seen. In head and neck squamous cell carcinomas (HNSCC), there have been conflicting results regarding the association between nm-23 protein expression and metastatic potential. To further explore the tumor metastasis suppressor function of nm-23 in HNSCC, we studied high-stage laryngeal carcinomas, tumors with and without cervical lymph node metastasis for nm-23 protein expression and loss of heterozygosity of the gene locus. Twenty-five cases were included (11 cases with and 14 cases without metastasis). Loss of heterozygosity for the nm-23 gene locus was seen in 7 of 22 (32%) informative tumors. Using immunohistochemistry, most tumors expressed nm-23, though decreased expression was seen in 10 of 25 (40%) cases. Only 2 tumors showed negative expression. We did not find a correlation between either protein expression or loss of heterozygosity with metastatic disease or any other adverse prognostic factors in this group of high-stage laryngeal squamous cell carcinomas. These data imply that nm-23 may be tumor suppressor gene involved in HNSCC but that it may not function as a tumor metastasis suppressor in high-stage laryngeal carcinoma.     

Role of the nm23-H1 gene in the metastasis of gastric cancer.

The nm23 gene is now generally accepted as one of the suppressor genes for metastasis in many types of human cancer. To investigate the role of the nm23 gene in gastric cancer, we examined the expression of nm23-H1 mRNA, mutations, and loss of heterozygosity (LOH) of the nm23-H1 gene in gastric cancers. The expression of nm23-H1 mRNA was examined by Northern blot analysis in eight paired sets of specimens. The expression was higher in primary cancer specimens and metastatic lymph nodes than their corresponding normal gastric mucosa in all eight sets of specimens examined, while it was similar between primary cancer specimens and metastatic lymph nodes. The mutations of the nm23-H1 gene were examined in an additional 11 sets of specimens, including eight sets of analysed by Northern blotting, by polymerase chain reaction single-strand conformation polymorphism analysis, no mutation being found in any of the 11 sets of specimens tested. LOH of the nm23-H1 gene was also examined in additional 12 sets of specimens, among which seven (58%) specimens were informative for LOH. LOH was identified in one (14%) out of these seven informative sets. These results suggest that nm23 may not be the metastasis suppressor gene and the alteration of this gene not play an important role in the process of metastasis of gastric cancer.