KAI－1基因在晚期肾癌中表达降低
作者：孔宪国 张元芳 丁强 王忠 黄国华
单位：孔宪国 黄国华(上海铁道大学附属铁路医院泌尿外科，上海200072)；张元芳 丁强 王忠(上海医科大学华山医院泌尿外科，上海200040)
关键词：肾肿瘤；KAI-1；转移
癌症000614
【摘要】目的：探讨KAI-1mRNA在肾细胞癌中的表达及与浸润转移的关系。方法：采用RT-PCR方法检测35例肾癌及癌周正常肾组织KAI-1mRNA的表达。结果：肾癌组织中KAI-1表达率明显低于癌周正常组织(P<0.05);有肾周浸润或局部淋巴结转移的患者(Ⅲ、Ⅳ期)骨癌组织中KAI-1表达明显低于Ⅰ、Ⅱ期患者(P<0.05)。结论：KAI-1基因的低表达可能与肾细胞癌的进展有关。
中图分类号：R737.11 文献标识码：A
, http://www.100md.com
文章编号：1000-467X(2000)06-0554-04
Decreased KAI-1 expression in advanced renal cell carcinoma
KONG Xian-guo
Department of Urology,Affiliated Tielu Hospital, Shanghai Tiedao University,Shanghai 200072,P.R.China
ZHANG Yuan-fang, DING Qiang, et al.
Department of Urology,Huashan Hospital,Shanghai Medical University,Shanghai 200040,P.R.China
, 百拇医药
【 Abstract】 Objective： To investigate the expression of KAI-1 mRNA in renal cell carcinoma and the relationship with the metastasis. Method： RT-PCR was used to detect KAI-1 mRNA expression in specimens from 35 cases with renal cancer and adjacent normal kidney tissues. Results： KAI-1 expression rate in renal cancer was significantly lower than that in normal kidney tissues (P< 0.05); tumors of patients with extrarenal invasion or regional lymph node metastasis (stage Ⅲ orⅣ ) had significantly lower KAI-1 expression levels than tumors of patients with stage Ⅰ or Ⅱ disease (P< 0.05).Conclusion： Decreased expression of the KAI-1 gene may be related to disease progression in patients with renal cancer.
, http://www.100md.com
Key words： Kidney neoplasms; KAI-1; Metastasis
Metastasis, the main cause of death for most cancer patients, remains one of the most important but least understood aspects of cancer. Both positive and negative regulators of metastasis are likely to exist. A recently discovered antimetastatic gene that is present in prostate cancer has been named KAI- 1. When human prostate cancer samples were transplanted into nude mice, KAI- 1 was found to suppress the ability of prostate cancer cells to metastasize[1]. KAI- 1 expression appears to be reduced in human cell lines that derive from metastatic prostate tumors, compared with its expression in normal prostate tissue[1].
, 百拇医药
The KAI- 1 gene is located on human chromosome 11P11.2～ 13 and encodes a protein of 267 amino acids with a molecular mass of 29 610 daltons. KAI- 1 belongs to a structurally distinct family of membrane glycoproteins.They function in cell- cell and cell- extracellular matrix interactions, thereby potentially influencing the ability of cancer cells to invade tissue and to metastasize[1]. The importance of KAI- 1 in cancers other than prostate cancer has been evaluated, KAI- 1 expression is up regulated in early pancreatic cancer and decreased in the presence of metastases[2], and decreased mRNA expression of KAI- 1 correlates with poor prognosis in patients with non small cell lung cancer[3].
, 百拇医药
Renal cell carcinomas (RCC) is known to meta- stasize early, and histological features such as cell type, architecture, and tumor grade are of limited prognostic value. Many of the renal cancer patients exhibit evidence for metastatic disease at the time of diagnosis. The reasons for the proclivity of renal cancer cells to metastasize are not known. The aim of the present study was to determine whether there are alterations in KAI- 1 expression in primary renal cancers and evaluate whether KAI- 1 mRNA expression correlates with clinical parameters of renal cancer patients.
, http://www.100md.com
1 MATERIALS AND METHODS
1.1 Patients
We studied 35 patients with RCC who underwent surgery between December 1995 and May 1998 at the Department of Urology of Shanghai Huashan Hospital. Their clinical records and histopathological diagnoses were fully documented. According to the Robsin classification of renal cancer, there were 7 patients with stageⅠ disease, 15 patients with stageⅡ ,7 patients with stageⅢ , and 6 patients with stageⅣ .
, http://www.100md.com
1.2 Tissue Sampling
Renal cancer tissue samples and adjacent normal kidney tissue samples were frozen in liquid nitrogen immediately after surgical removal and maintained at - 80℃ until use.
1.3 RT- PCR Analysis
Total cellular RNA was purified from frozen tumor or kidney tissues by the acid guanidinium thiocyanate procedure[4]. On the basis of the nucleotide sequence of KAI- 1[1],5＇- CAAGATCTATGGGCTCAGCCTGTAT- CAAAGTCACC- 3＇ was used as the sense primer and 5＇-CCAAGCTTTCAGTACTTGGGGACCTTGCTGTAGTC- 3＇as the antisense primer. This primer pair amplifies a 798bp fragment (nucleotides 168- 965). The reaction mixture was subjected to 30 PCR amplification cycles of 50s at 94℃ , 75s at 54℃ , and 90s at 72℃ . β- actin DNA amplification was used as the internal PCR control[5];the sense primer was 5＇- CTATTGGCA- ACGAGCGGTTC- 3＇ , and the antisense primer was 5＇ CTTAGGAGTGGGGGTGGCTT- 3＇ .The same PCR conditions were used to amplify β-actin DNA, the amplified fragment was 776bp. Tubes containing all ingridents except templates were included in all runs and served as negative reaction controls. The amplified DNA samples were run on a 1.5% agarose gel, and bands were visualized with ethidium bromide and photographed with a camera. Densitometric analysis of the photographic negatives was used for band quantification[6].
, http://www.100md.com
1.4 Specimen Classification Based on RT- PCR Results
The value obtained for KAI- 1 by densitometry of the band of a given tissue sample was divided by that of β- actin and was referred to as the KAI- 1 expression ratio. When the ratio value of a given specimen was ≥ 0.2, it was considered to indicate positive, and if the value was <0.2, it was considered as denoting negative expression.
1.5 Statistical Analysis
, http://www.100md.com
The statistical significance of the difference between the incidence of KAI 1 positive expression and several clinical and pathological parameters was assessed by the exact text for 2× 2 table, P<0.05 was considered to indicate statistical significance.
2 RESULTS
2.1 KAI- 1 Expression in Renal Cancer and Normal Kidney Tissues Analyzed by Quantitative RT- PCR
The KAI- 1 expression ratio ranged from 0 to 1.2 with a mean of 0.748. All the normal kidney tissues were positive. Of the 35 primary renal cancer cases studied, 25(71.4% ) were positive and 10(28.6% ) were negative(Fig.1). KAI- 1 expression rate in cancer was significantly lower than that in normal kidney tissues(P<0.05).
, http://www.100md.com
2.2 Relationship between KAI- 1 Gene Expre- ssion and Known Prognostic Factors
Analysis of the 35 patients whose renal cancers were tested for KAI- 1 gene expression revealed that there were no statistically significant relationships (χ2 test) between gene expression and the patients- age at surgery or sex. By contrast, KAI- 1 expression was significantly associated with tumor stage (P<0.05; table 1). Tumors of patients with extrarenal invasion or regional lymph node metastasis (stageⅢ or Ⅳ ) had significantly lower KAI- 1 expression levels than tumors of patients with stage Ⅰ or stageⅡ disease.
, 百拇医药
3 DISCUSSION
The accurate prediction of the metastatic potential of tumors (the probability that cancer cells will move from the primary tumor to colonize in distant organs) is an important goal in clinical oncology. The ability of cancer cells to spread and to grow in lymph nodes and distant organs often predicts the clinical outcome and survival period of the patient. In renal cancer, most patients are diagnosed in advanced stages when the tumor has already spread. This clinical characteristic suggests that mechanisms might exist in renal cancer that support the metastasizing ability of the cancer cells.
, 百拇医药
Recently, Barrett et al.[1]identified KAI- 1, a gene that suppresses the ability of human prostate cancer cells to metastasize when tumor samples are transplanted into nude mice. Our present analysis describes for the first time the expression of KAI- 1 mRNA in human renal cancer. We observed decreased KAI- 1 mRNA levels in the renal cancer tissues analysed by quantitative RT- PCR. However, the cancer samples exhibited varying levels of KAI- 1 mRNA expression, and tumors in advanced stages had significant lower expression than tumors in early stages. These findings indicate that KAI- 1 is highly expressed in the normal kidney tissue, and during cancer development, KAI- 1 gene is partially or completely inactivated.
, http://www.100md.com
The present data show that decreased expression of the KAI- 1 gene may be related to disease progression in patients with renal cancer. KAI- 1 mRNA levels were significantly lower in tumors with concomitant lymph node metastasis or extrarenal invasion than in tumors confined to the kidney. These results indicate that KAI- 1 may have a relationship to the metastatic potential of the tumor and that thereduction of KAI- 1 expression during tumor pathogenesis might lead to lymph node metastasis or extrarenal invasion.
, 百拇医药
KAI- 1 belongs to a structurally distinct family of membrane glycoproteins[7], most of which have been first indentified as leukocyte surface proteins. Although the biological functions of these proteins are mostly unknown , their membranous locations and extensive glycosylation suggest that they function in cell attachment and cell extracellular matrix interactions, both of which are important in tumor invasion and metastasis. Furthermore, in addition to KAI- 1 expression, expression of two other members of this gene family has been correlated with the metastatic potential of tumor cells. The MRP- 1 gene product is involved in cell penetration and motility, in vitro parameters for metastasis[8]. Motility plays a very important role in tumor invasion and metastasis. Likewise, reduction or loss of ME491/CD63 expression, a 237- amino acid cell surface glycoprotein, is associated with increased metastatic ability of human malignant melanoma[9].
, 百拇医药
Fig.1 A. Agarose gel electrophoresis of RT- PCR- amplified 798bp KAI- 1 cDNA
B. Agarose gel electrophoresis of amplified β- actin DNA (internal PCR control) of each specimen
M： Marker; Lane 1: RCC with positive KAI- 1 expression; Lanes3， 5： RCC with negative KAI- 1 expression; Lanes 2， 4， 6： normal kidney tissues with positive KAI- 1 expression.
Table 1 Relationship of KAI- 1 gene expression and various prognostic factors Characteristics
, 百拇医药
Total(n)
KAI-1
status
P
(+)
(-)
Age at Surgery(a)
≤ 60
21
15
6
>0.05
>60
, http://www.100md.com
14
10
4
Sex
Female
10
8
2
>0.05
Male
25
17
8
, 百拇医药 Clinical stage
Stage Ⅰ,Ⅱ
22
19
3
<0.05
Stage Ⅲ,Ⅳ
13
6
7
Histology
Clear cell carcinoma
, 百拇医药 26
18
8
>0.05
Granular cell carcinoma
9
7
2
Exact test for 2× 2 table
Our first study in renal cancer shows that KAI- 1 is involved in the metastasis of these tumors. Howerer, the mechanism of KAI- 1 down- regulation is not clear[10], and the role of KAI- 1 in the mechanisms of tumor metastasis is still required further determination.
, 百拇医药
[REFERENCE]
1，Dong JT, Lamb PW, Rinker-Schaeffer CW, et al. KAI1, a metastasis suppressor gene for prostate cancer on human chromosome 11P11,2 [J]. Science,1995,268： 884～ 886.
2，Guo X, Friess H, Graber HU, et al. KAI1 expression is up-regulated in early pancreatic cancer and decreased in the presence of metastases [J]. Cancer Res, 1996, 56 ： 4876～ 4880.
3，Adachi M , Taki T, Ieki Y, et al. Correlation of KAI1/CD82 gene expression with good prognosis in patients with non-small cell lung cancer [J]. Cancer Res,1996, 56： 1751～ 1755.
, http://www.100md.com
4，Chomczynski P, Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction[J]. Anal Biochem, 1987, 162： 156～ 159.
5，Nakajima-Iijima S, Hamada H, Reddy P, et al. Molecular structure of the human cytoplasmic β -actin gene ： interspecies homology of sequences in the introns [J]. Proc Natl Acad Sci USA, 1985,82： 6133～ 6137.
6，Scheck AC, Mehta BM, Beikman MK, et al. BCNU-resistant human glioma cells with overpresentation of chromosomes 7 and 22 demonstrate increased copy number and expression of platelet-derived growth factor genes [J]. Genes Chromosomes ＆ Cancer, 1993, 8： 137～ 148.
, http://www.100md.com
7，Horejsi V, Vlcek C. Novel structurally distinct family of leukocyte surface glycoproteins including CD9, CD37, CD53, and CD63 [J]. FEBS Lett, 1991,288： 1～ 4.
8，Miyake M, Koyama M, Seno M, et al. Identification of the motility-related protein (MRP-1), recognized by monoclonal antibody M31-15, which inhibits cell motility [J]. Exp J Med, 1991,174： 1347～ 1354.
9，Metzelaar MJ, Wijngaard PLJ, Peters PJ, et al. CD63 antigen [J]. J Biol Chem, 1991,266： 3239～ 3245.
10，Dong JT, Suzuki H, Pin SS, et al. Down-regulation of the KAI1 metastasis suppressor gene during the progression of human prostatic cancer infrequently involves gene mutation or allelic loss [J]. Cancer Res , 1996, 56： 4387～ 4390.
收稿日期：1999-08-11;修回日期:1999-09-24, 百拇医药
单位：孔宪国 黄国华(上海铁道大学附属铁路医院泌尿外科，上海200072)；张元芳 丁强 王忠(上海医科大学华山医院泌尿外科，上海200040)
关键词：肾肿瘤；KAI-1；转移
癌症000614
【摘要】目的：探讨KAI-1mRNA在肾细胞癌中的表达及与浸润转移的关系。方法：采用RT-PCR方法检测35例肾癌及癌周正常肾组织KAI-1mRNA的表达。结果：肾癌组织中KAI-1表达率明显低于癌周正常组织(P<0.05);有肾周浸润或局部淋巴结转移的患者(Ⅲ、Ⅳ期)骨癌组织中KAI-1表达明显低于Ⅰ、Ⅱ期患者(P<0.05)。结论：KAI-1基因的低表达可能与肾细胞癌的进展有关。
中图分类号：R737.11 文献标识码：A
, http://www.100md.com
文章编号：1000-467X(2000)06-0554-04
Decreased KAI-1 expression in advanced renal cell carcinoma
KONG Xian-guo
Department of Urology,Affiliated Tielu Hospital, Shanghai Tiedao University,Shanghai 200072,P.R.China
ZHANG Yuan-fang, DING Qiang, et al.
Department of Urology,Huashan Hospital,Shanghai Medical University,Shanghai 200040,P.R.China
, 百拇医药
【 Abstract】 Objective： To investigate the expression of KAI-1 mRNA in renal cell carcinoma and the relationship with the metastasis. Method： RT-PCR was used to detect KAI-1 mRNA expression in specimens from 35 cases with renal cancer and adjacent normal kidney tissues. Results： KAI-1 expression rate in renal cancer was significantly lower than that in normal kidney tissues (P< 0.05); tumors of patients with extrarenal invasion or regional lymph node metastasis (stage Ⅲ orⅣ ) had significantly lower KAI-1 expression levels than tumors of patients with stage Ⅰ or Ⅱ disease (P< 0.05).Conclusion： Decreased expression of the KAI-1 gene may be related to disease progression in patients with renal cancer.
, http://www.100md.com
Key words： Kidney neoplasms; KAI-1; Metastasis
Metastasis, the main cause of death for most cancer patients, remains one of the most important but least understood aspects of cancer. Both positive and negative regulators of metastasis are likely to exist. A recently discovered antimetastatic gene that is present in prostate cancer has been named KAI- 1. When human prostate cancer samples were transplanted into nude mice, KAI- 1 was found to suppress the ability of prostate cancer cells to metastasize[1]. KAI- 1 expression appears to be reduced in human cell lines that derive from metastatic prostate tumors, compared with its expression in normal prostate tissue[1].
, 百拇医药
The KAI- 1 gene is located on human chromosome 11P11.2～ 13 and encodes a protein of 267 amino acids with a molecular mass of 29 610 daltons. KAI- 1 belongs to a structurally distinct family of membrane glycoproteins.They function in cell- cell and cell- extracellular matrix interactions, thereby potentially influencing the ability of cancer cells to invade tissue and to metastasize[1]. The importance of KAI- 1 in cancers other than prostate cancer has been evaluated, KAI- 1 expression is up regulated in early pancreatic cancer and decreased in the presence of metastases[2], and decreased mRNA expression of KAI- 1 correlates with poor prognosis in patients with non small cell lung cancer[3].
, 百拇医药
Renal cell carcinomas (RCC) is known to meta- stasize early, and histological features such as cell type, architecture, and tumor grade are of limited prognostic value. Many of the renal cancer patients exhibit evidence for metastatic disease at the time of diagnosis. The reasons for the proclivity of renal cancer cells to metastasize are not known. The aim of the present study was to determine whether there are alterations in KAI- 1 expression in primary renal cancers and evaluate whether KAI- 1 mRNA expression correlates with clinical parameters of renal cancer patients.
, http://www.100md.com
1 MATERIALS AND METHODS
1.1 Patients
We studied 35 patients with RCC who underwent surgery between December 1995 and May 1998 at the Department of Urology of Shanghai Huashan Hospital. Their clinical records and histopathological diagnoses were fully documented. According to the Robsin classification of renal cancer, there were 7 patients with stageⅠ disease, 15 patients with stageⅡ ,7 patients with stageⅢ , and 6 patients with stageⅣ .
, http://www.100md.com
1.2 Tissue Sampling
Renal cancer tissue samples and adjacent normal kidney tissue samples were frozen in liquid nitrogen immediately after surgical removal and maintained at - 80℃ until use.
1.3 RT- PCR Analysis
Total cellular RNA was purified from frozen tumor or kidney tissues by the acid guanidinium thiocyanate procedure[4]. On the basis of the nucleotide sequence of KAI- 1[1],5＇- CAAGATCTATGGGCTCAGCCTGTAT- CAAAGTCACC- 3＇ was used as the sense primer and 5＇-CCAAGCTTTCAGTACTTGGGGACCTTGCTGTAGTC- 3＇as the antisense primer. This primer pair amplifies a 798bp fragment (nucleotides 168- 965). The reaction mixture was subjected to 30 PCR amplification cycles of 50s at 94℃ , 75s at 54℃ , and 90s at 72℃ . β- actin DNA amplification was used as the internal PCR control[5];the sense primer was 5＇- CTATTGGCA- ACGAGCGGTTC- 3＇ , and the antisense primer was 5＇ CTTAGGAGTGGGGGTGGCTT- 3＇ .The same PCR conditions were used to amplify β-actin DNA, the amplified fragment was 776bp. Tubes containing all ingridents except templates were included in all runs and served as negative reaction controls. The amplified DNA samples were run on a 1.5% agarose gel, and bands were visualized with ethidium bromide and photographed with a camera. Densitometric analysis of the photographic negatives was used for band quantification[6].
, http://www.100md.com
1.4 Specimen Classification Based on RT- PCR Results
The value obtained for KAI- 1 by densitometry of the band of a given tissue sample was divided by that of β- actin and was referred to as the KAI- 1 expression ratio. When the ratio value of a given specimen was ≥ 0.2, it was considered to indicate positive, and if the value was <0.2, it was considered as denoting negative expression.
1.5 Statistical Analysis
, http://www.100md.com
The statistical significance of the difference between the incidence of KAI 1 positive expression and several clinical and pathological parameters was assessed by the exact text for 2× 2 table, P<0.05 was considered to indicate statistical significance.
2 RESULTS
2.1 KAI- 1 Expression in Renal Cancer and Normal Kidney Tissues Analyzed by Quantitative RT- PCR
The KAI- 1 expression ratio ranged from 0 to 1.2 with a mean of 0.748. All the normal kidney tissues were positive. Of the 35 primary renal cancer cases studied, 25(71.4% ) were positive and 10(28.6% ) were negative(Fig.1). KAI- 1 expression rate in cancer was significantly lower than that in normal kidney tissues(P<0.05).
, http://www.100md.com
2.2 Relationship between KAI- 1 Gene Expre- ssion and Known Prognostic Factors
Analysis of the 35 patients whose renal cancers were tested for KAI- 1 gene expression revealed that there were no statistically significant relationships (χ2 test) between gene expression and the patients- age at surgery or sex. By contrast, KAI- 1 expression was significantly associated with tumor stage (P<0.05; table 1). Tumors of patients with extrarenal invasion or regional lymph node metastasis (stageⅢ or Ⅳ ) had significantly lower KAI- 1 expression levels than tumors of patients with stage Ⅰ or stageⅡ disease.
, 百拇医药
3 DISCUSSION
The accurate prediction of the metastatic potential of tumors (the probability that cancer cells will move from the primary tumor to colonize in distant organs) is an important goal in clinical oncology. The ability of cancer cells to spread and to grow in lymph nodes and distant organs often predicts the clinical outcome and survival period of the patient. In renal cancer, most patients are diagnosed in advanced stages when the tumor has already spread. This clinical characteristic suggests that mechanisms might exist in renal cancer that support the metastasizing ability of the cancer cells.
, 百拇医药
Recently, Barrett et al.[1]identified KAI- 1, a gene that suppresses the ability of human prostate cancer cells to metastasize when tumor samples are transplanted into nude mice. Our present analysis describes for the first time the expression of KAI- 1 mRNA in human renal cancer. We observed decreased KAI- 1 mRNA levels in the renal cancer tissues analysed by quantitative RT- PCR. However, the cancer samples exhibited varying levels of KAI- 1 mRNA expression, and tumors in advanced stages had significant lower expression than tumors in early stages. These findings indicate that KAI- 1 is highly expressed in the normal kidney tissue, and during cancer development, KAI- 1 gene is partially or completely inactivated.
, http://www.100md.com
The present data show that decreased expression of the KAI- 1 gene may be related to disease progression in patients with renal cancer. KAI- 1 mRNA levels were significantly lower in tumors with concomitant lymph node metastasis or extrarenal invasion than in tumors confined to the kidney. These results indicate that KAI- 1 may have a relationship to the metastatic potential of the tumor and that thereduction of KAI- 1 expression during tumor pathogenesis might lead to lymph node metastasis or extrarenal invasion.
, 百拇医药
KAI- 1 belongs to a structurally distinct family of membrane glycoproteins[7], most of which have been first indentified as leukocyte surface proteins. Although the biological functions of these proteins are mostly unknown , their membranous locations and extensive glycosylation suggest that they function in cell attachment and cell extracellular matrix interactions, both of which are important in tumor invasion and metastasis. Furthermore, in addition to KAI- 1 expression, expression of two other members of this gene family has been correlated with the metastatic potential of tumor cells. The MRP- 1 gene product is involved in cell penetration and motility, in vitro parameters for metastasis[8]. Motility plays a very important role in tumor invasion and metastasis. Likewise, reduction or loss of ME491/CD63 expression, a 237- amino acid cell surface glycoprotein, is associated with increased metastatic ability of human malignant melanoma[9].
, 百拇医药
Fig.1 A. Agarose gel electrophoresis of RT- PCR- amplified 798bp KAI- 1 cDNA
B. Agarose gel electrophoresis of amplified β- actin DNA (internal PCR control) of each specimen
M： Marker; Lane 1: RCC with positive KAI- 1 expression; Lanes3， 5： RCC with negative KAI- 1 expression; Lanes 2， 4， 6： normal kidney tissues with positive KAI- 1 expression.
Table 1 Relationship of KAI- 1 gene expression and various prognostic factors Characteristics
, 百拇医药
Total(n)
KAI-1
status
P
(+)
(-)
Age at Surgery(a)
≤ 60
21
15
6
>0.05
>60
, http://www.100md.com
14
10
4
Sex
Female
10
8
2
>0.05
Male
25
17
8
, 百拇医药 Clinical stage
Stage Ⅰ,Ⅱ
22
19
3
<0.05
Stage Ⅲ,Ⅳ
13
6
7
Histology
Clear cell carcinoma
, 百拇医药 26
18
8
>0.05
Granular cell carcinoma
9
7
2
Exact test for 2× 2 table
Our first study in renal cancer shows that KAI- 1 is involved in the metastasis of these tumors. Howerer, the mechanism of KAI- 1 down- regulation is not clear[10], and the role of KAI- 1 in the mechanisms of tumor metastasis is still required further determination.
, 百拇医药
[REFERENCE]
1，Dong JT, Lamb PW, Rinker-Schaeffer CW, et al. KAI1, a metastasis suppressor gene for prostate cancer on human chromosome 11P11,2 [J]. Science,1995,268： 884～ 886.
2，Guo X, Friess H, Graber HU, et al. KAI1 expression is up-regulated in early pancreatic cancer and decreased in the presence of metastases [J]. Cancer Res, 1996, 56 ： 4876～ 4880.
3，Adachi M , Taki T, Ieki Y, et al. Correlation of KAI1/CD82 gene expression with good prognosis in patients with non-small cell lung cancer [J]. Cancer Res,1996, 56： 1751～ 1755.
, http://www.100md.com
4，Chomczynski P, Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction[J]. Anal Biochem, 1987, 162： 156～ 159.
5，Nakajima-Iijima S, Hamada H, Reddy P, et al. Molecular structure of the human cytoplasmic β -actin gene ： interspecies homology of sequences in the introns [J]. Proc Natl Acad Sci USA, 1985,82： 6133～ 6137.
6，Scheck AC, Mehta BM, Beikman MK, et al. BCNU-resistant human glioma cells with overpresentation of chromosomes 7 and 22 demonstrate increased copy number and expression of platelet-derived growth factor genes [J]. Genes Chromosomes ＆ Cancer, 1993, 8： 137～ 148.
, http://www.100md.com
7，Horejsi V, Vlcek C. Novel structurally distinct family of leukocyte surface glycoproteins including CD9, CD37, CD53, and CD63 [J]. FEBS Lett, 1991,288： 1～ 4.
8，Miyake M, Koyama M, Seno M, et al. Identification of the motility-related protein (MRP-1), recognized by monoclonal antibody M31-15, which inhibits cell motility [J]. Exp J Med, 1991,174： 1347～ 1354.
9，Metzelaar MJ, Wijngaard PLJ, Peters PJ, et al. CD63 antigen [J]. J Biol Chem, 1991,266： 3239～ 3245.
10，Dong JT, Suzuki H, Pin SS, et al. Down-regulation of the KAI1 metastasis suppressor gene during the progression of human prostatic cancer infrequently involves gene mutation or allelic loss [J]. Cancer Res , 1996, 56： 4387～ 4390.
收稿日期：1999-08-11;修回日期:1999-09-24, 百拇医药