CDKN2／p16^INK4a基因克隆,探针制备及其在肺癌基因诊断中的 …

OBJECTIVES: To clone CDKN2/p16(INK4a) gene, prepare its probe, and to study the change of CDKN2/p16(INK4a) gene in lung cancers. METHODS: Total RNA of normal lung tissue was extracted, CDKN2/p16(INK4a) gene cDNA synthesized, and CDKN2/p16(INK4a) gene recombinant vector, constructed. Southern blot was used to study CDKN2/p16(INK4a) gene in 46 cases of lung cancers, 3 cases of normal lung tissues, 6 cases of lung tissues near cancer, and 3 cases of lymph nodes with lung cancer metastasis. RESULTS: Cloned CDKN2/p16(INK4a) cDNA was proved by enzyme digestion and sequencing. Southern blot showed 4.3 kb band in normal lung tissues and lung tissues near cancers, and deletion of CDKN2/p16(INK4a) gene in cancer tissues and lymph nodes with lung cancer metastasis, with a deletion rate of 17.4% (8/46). CONCLUSION: CDKN2/p16(INK4a) gene may play a role to some extent in progression of lung cancers.     

CDKN2/p16基因存在状态与肺癌

目的　研究CDKN2 /p16基因缺失和蛋白丢失在肺癌发展中的作用。方法　采用免疫组化和改良标本处理的PCR技术 ,对 89例肺癌病人手术标本CDKN2 /p16基因第 1、2外显子纯合缺失和P16蛋白表达丢失情况进行分析对比研究。结果　CDKN2 /p16基因第 1或 (和 )第 2外显子总缺失率为2 5 8% (2 3/ 89) ,P16蛋白丢失率为 47 2 % (4 2 / 89) ,基因的缺失和蛋白的丢失集中发生于非小细胞肺癌(NSCLC) ,并与转移和分期有关。结论　CDKN2 /p16基因的异常可能是NSCLC区别于小细胞肺癌(SCLC)的特有的分子事件 ,其在NSCLC的发生发展中起一定的负调控作用     

不同时期胃癌中p16基因缺失和突变的研究

目的　探讨p16基因纯和缺失和突变与胃癌发生的关系。方法　采用PCR、多重PCR、PCR SSCP和DNA测序技术分析 5 0例胃癌组织中p16基因的表达情况 ,其中早期胃癌 7例 ,进展期胃癌 43例。结果　p16基因总的点突变频率为 8.0 0 % (4 5 0 ) ,早期胃癌为 14 .2 9% (1 7) ,进展期胃癌为 6.98% (3 4 3 ) ,两者比较差异无显著性意义 (P>0 .0 5 ) ;p16基因突变与肿瘤的大小、位置、分化程度和有无淋巴结转移无关 (P>0 .0 5 )。p16基因总的纯和缺失频率为 16.0 0 % (8 5 0 ) ,早期胃癌为 0 (0 7) ,进展期胃癌为 18.60 % (8 4 3 ) ,两者比较差异有显著性意义 (P<0 .0 5 ) ;p16基因缺失频率与肿瘤分化程度和有无淋巴结转移有关 (P<0 .0 5 )。结论　p16基因点突变是胃癌发生的早期事件 ,对胃癌早期诊断有一定帮助 ;p16基因纯和缺失是胃癌的晚期事件 ,可能与胃癌的转移和复发有关。     

胃肠间质瘤中9p21区域杂合子丢失及P16蛋白表达研究

目的 探讨染色体9p21区域杂合子丢失（LOH）及相关的P16INK4A（CDKN2A）抑癌基因的表达与胃肠间质瘤（GIST）侵袭行为及预后的关系.方法 采用微卫星分析方法检测51例GIST标本中9p21区域D9S1751、D9S1846、D9S942和D9S1748 4个微卫星位点的LOH现象,并采用免疫组织化学技术,对D9S942位点相邻的CDKN2A抑癌基因产物P16蛋白的表达,分析P16蛋白表达缺失与GIST临床病理特征和预后的关系.结果 51例GIST标本中有2例9p21区域4个微卫星位点均为纯合子（无效信息）,其余49例9p21区域的LOH率：D9S1751为37.0%（10/27）、D9S1846为37.5%（12/32）、D9S942为42.1%（16/38）、D9S1748为24.2%（8/33）,总LOH率为63.3%（31/49）.P16蛋白在GIST标本中的阴性表达率为41.2%（21/51）,阳性率为58.8%（30/51）.高度与低或极低度侵袭风险组P16阴性表达率分别为60%（12/20）和23.5%（4/17）,差异有统计学意义（P＜0.05）.P16阴性与阳性表达组5年生存率分别为70.8%和92.0%,差异有统计学意义（P＜0.05）.结论 9p21区域的LOH在GIST中普遍存在 CDKN2A抑癌基因可能参与GIST的发生发展 P16蛋白与GIST侵袭风险及预后关系密切.     

Primary lymphoma of peripheral nerve: report of four cases

Lymphoma presenting as a solitary tumor of peripheral nerve is exceedingly rare, with only six previously reported cases. The authors describe an additional four cases of primary lymphoma of peripheral nerve involving the sciatic nerve (two cases), the radial nerve, and the sympathetic chain and spinal nerve. The patients were two men and two women with an average age of 55.5 years. All tumors were high-grade B-cell lymphomas. Two patients experienced relapse of disease with involvement of other nervous system sites and died of lymphoma. One patient is alive with stable local disease at 57 months. The fourth patient is alive with no evidence of disease at 54 months. Expression of neural cell adhesion molecule (CD56) has been reported to correlate with an increased incidence of central nervous system involvement in peripheral T-cell lymphoma; all their cases were CD56 negative. Recent reports indicate a high proportion of primary brain lymphomas show loss of CDKN2A/p16 gene expression. Therefore, CDKN2A/p16 was evaluated in their patients both by polymerase chain reaction and by immunohistochemistry for the p16 protein. The authors found homozygous deletion of the CDKN2A/p16 gene in one of three patients studied, confirmed immunohistochemically by absent staining for p16. The fourth patient showed absent staining for p16, suggesting inactivation of the gene in this case as well. The two patients with p16 loss both died of lymphoma, whereas the two patients with normal p16 expression are alive. Primary lymphoma of peripheral nerve is a rare neoplasm, usually of large B-cell type, has a variable prognosis, and appears to have less consistent loss of p16 expression than primary central nervous system lymphoma.     

人肠癌RKO细胞周期依赖性激抑制因子基因启动子区甲基化状态的研究

目的 探讨人结肠癌RKO细胞周期依赖性激酶抑制因子(CKIs)家族启动子区CpG岛甲基化状态及其甲基化可逆性特征.方法 应用特异性DNA甲基转移酶(DNMTs)抑制剂5-Aza-2]-deoxycytidine(5-Aza-CdR)处理肠癌细胞,甲基特异性聚合酶链反应(Methylation-Specific PCR,MSP)、T-A克隆及DNA测序法分析RKO细胞CKIs家族抑癌基因p15ink4b、p16ink4a/CDKN2、p21/cip、p27/kip启动子CpG岛甲基化状态.结果 未经5-Aza-CdR作用的肠癌RKO细胞,其p15ink4b、p16ink4a/CDKN2基因组DNA胞嘧啶(C)保持不变,这提示在其单链DNA中胞嘧啶呈甲基化状态;而经5-Aza-CdR作用的肠癌RKO细胞,其p15ink4b、p16ink4a/CDKN2、p21/cip和p27/kip基因组DNA胞嘧啶均已变为胸腺嘧啶,表明在DNA单链中胞嘧啶已呈去甲基化状态.结论 肠癌RKO细胞周期INK4家族(p15ink4b和p16ink4a/CDKN2)基因的启动子区处于异常的高甲基化状态,而KIP/CIP家族(p21/cip和p27/kip)基因未处于高甲基化状态;5-Aza-CdR能较好地逆转肿瘤细胞INK4家族基因DNA高甲基化状态.     

Genetic analysis of invasive carcinoma arising in intraductal oncocytic papillary neoplasm of the pancreas

A case of intraductal oncocytic papillary neoplasm of the pancreas, with the rare progression to invasive carcinoma, is described. The intraductal oncocytic papillary neoplasm component had the features typical of this entity, with stratified layers of oncocytic cuboidal tumor cells growing in papillary and pseudopapillary arrangements within dilated pancreatic ducts. The invasive carcinoma formed a discrete fleshy tumor with well-circumscribed borders. The invasive carcinoma grew in solid lobules, subdivided by fine fibrovascular septae into predominantly organoid and trabecular growth patterns. Molecular analysis showed no loss of heterozygosity for microsatellite markers at the tumor suppressor loci of TP53, CDKN2A (p16/INK4A), and MADH4 (Smad4/DPC4) in the invasive carcinoma, although loss of heterozygosity was detected at one CDKN2A marker in the intraductal component. DNA sequencing of polymerase chain reaction amplification products of exons 1 and 2 of the CDKN2A gene showed no mutation in either tumor component. TP53 immunohistochemistry showed no increased levels of staining, consistent with the presence of wild-type gene product. Polymerase chain reaction and DNA sequencing showed no mutation of codons 12 and 13 of the KRAS proto-oncogene. These results suggest that intraductal oncocytic papillary neoplasm is a neoplasm with genetic changes that are distinct from typical pancreatic adenocarcinoma. The lack of mutation in these genes may be an explanation for the typically indolent clinical behavior of intraductal oncocytic papillary neoplasms.     

Prognostic significance of homozygous deletions and multiple duplications at the CDKN2A (p16INK4a)/ARF (p14ARF) locus in urinary bladder cancer

OBJECTIVE: The 9p21 locus is a major target in the pathogenesis of human urinary bladder cancer. This locus harbours the CDKN2A/ARF tumour suppressor gene, which encodes two cell-cycle regulatory proteins: p16INK4a and p14ARF. We studied how homozygous deletions and multiple duplications at this locus affect prognosis and survival in patients with bladder cancer. MATERIAL AND METHODS: Real-time quantitative polymerase chain reaction (QPCR), based on simultaneous amplification of ARF and a reference gene, glyceraldehyde-3-phosphate dehydrogenase, was used to measure homozygous deletions and multiple duplications in a population-based material consisting of 478 patients with urinary bladder cancer. Results from real-time QPCR were compared with clinico-pathological parameters and survival curves were generated using the Kaplan-Meier method. RESULTS: Real-time QPCR analysis showed 71 (15%) homozygous deletions and 8 (2%) multiple duplications. We were unable to find any association between either stage or grade and urinary neoplasms with homozygous deletions. However, although there were only a limited number of patients with multiple duplications, 7/8 of them had highly malignant tumours (G2b-G4 or > or = T1; p = 0.02). CONCLUSIONS: Urinary bladder cancers constitute a spectrum of neoplasms with varying clinical manifestations. We were unable to establish a prognostic relevance for patients with tumours harbouring homozygous deletions at the CDKN2A/ARF locus. However, our data did indicate that patients with multiple duplications at the CDKN2A/ARF locus had poor survival. This suggests that multiple duplications, in combination with other genetic changes, have cooperative effects which have a negative outcome on urinary bladder cancer prognosis.     

Alterations in the regulatory pathway involving p16, pRb and cdk4 in human chondrosarcoma.

The G1 regulatory pathway involving p16, pRb and cdk4 in the cell cycle has been investigated in human chondrosarcoma. The protein expression of p16, pRb and cdk4 was analyzed by Western blot in cultured cells from eight chondrosarcomas and in two chondrosarcoma cell lines. Both cell lines and one other sample were negative for p16. Moreover, one of the cell lines was pRb-negative and showed a high expression of cdk4 as well. In the other cell line and in three other samples pRb of expected size were detected in addition to a shorter form of the protein. To further investigate the reasons for down-regulation of the p16 protein, the p16-coding gene CDKN2 was analyzed by polymerase chain reaction (PCR), methyl-specific PCR (MSP) and sequencing in all tumor samples as well as in corresponding tumor tissues from three of the samples. The p16-negative samples were all found to have homozygous deletion of CDKN2. Another sample showed partial gene methylation and a heterozygous position in codon 148 was detected in one sample. The same base substitution was also found in two of the tissue samples. Finally, cytogenetic analysis of the samples with homozygously deleted CDKN2 revealed multiple structural abnormalities in all three cases. In conclusion, the p16/pRb/cdk4 pathway may play an important role in the pathogenesis of some chondrosarcomas.     

骨肉瘤组织中p16基因的缺失突变及CDK4基因的扩增

目的 确定在原发性骨肉瘤中是否有Ｐ１６基因的异常及Ｐ１６基因异常与ＣＤＫ基因扩增之间的关系。方法 应用定量Ｓｏｕｔｈｅｒｎ ｂｌｏｔ方法分析确定Ｐ１６基因的缺失及ＣＤＫ基因的扩增。用ＰＣＲ＝ＳＳＣＰ方法检测Ｐ１６基因突变,结果：在６０例分析Ｐ１６基因的标本中有５例（９％）存在Ｐ１６基因的重排或缺失。均发生于原发肿瘤。在６７例分析ＣＤＫ４基因的标本中,有６例（９％）存在ＣＤＫ４基因的扩是有包括３例,     

Expression of p 16 protein in prostatic adenocarcinomas, intraepithelial neoplasia, and benign/hyperplastic glands

The tumor suppressor gene CDKN2/MTSI(p16(INK4)) may be inactivated by point mutations, deletions, or methylation in many tumor types. In prostate cancer, a very low frequency of point mutations has been reported, but deletions of 9p21 and inactivation by methylation are observed more frequently. The purpose of this study was to assess the expression pattern of the CDKN2 protein product p 16 in a series of 104 prostatic adenocarcinomas treated by radical prostatectomy, using immunohistochemical detection on archival, paraffin-embedded material. Nuclear staining was completely absent in 13 (13%) of 104 cases, whereas cytoplasmic staining was found in 99 (95%) of 104 carcinomas. Significant differences were found when comparing the staining intensity of carcinomas and coexisting prostatic intraepithelial neoplasia (PIN) with benign/hyperplastic glands. In 86 (95%) of 91 cases the overall staining intensity of carcinomas was stronger than the reactivity in benign/hyperplastic glands, which were most often weakly stained. In 71 (95%) of 75 cases the staining intensity of PIN was stronger than in benign/hyperplastic glands, a contrast also observed within single glands. However, p16 immunostaining in carcinomas was not prognostically important and it was not associated with standard clinicopathologic parameters. Our results support that CDKN2/plb is inactivated in only a small proportion of localized prostate cancers. The increased p16 staining of carcinomas/PIN in comparison with benign/hyperplastic glands suggests that p 16 protein may be involved in early stages of prostate tumorigenesis by mechanisms other than CDKN2/p16 gene inactivation, and the possibility of using p(16) immunostaining as a marker for PIN is discussed.     

p16INK4a expression and clinicopathologic parameters in renal cell carcinoma

OBJECTIVES: The tumour suppressor gene p16INK4a is a cyclin-dependent kinase inhibitor, for which inactivation attributable to promoter hypermethylation or homozygous deletion has been described in malignancies. Little is known about p16INK4a protein levels in renal cell carcinoma (RCC) and its association with clinicopathologic parameters or disease progression. METHODS: The expression of the p16INK4a gene was analysed with the use of immunohistochemistry and tissue microarrays (TMA). Tissue cores were obtained from the primary tumour itself, the tumoural invasion front, and histologically benign peritumoural tissue of 397 nephrectomies. For statistical analysis, sections were classified into four groups according to the relative amount of positively stained cells: negative (0%), low (1-10%), intermediate (11-50%), and high positivity (>50%). Follow-up data were analyzed for 198 patients (follow-up period: 2-240 mo; median: 138 mo). RESULTS: Absent or low expression of p16INK4a was observed in 82% of tumour samples. No statistically significant association was found between protein levels detected in tumour, invasion front, or normal renal tissues and any of the clinicopathologic variables. Survival analysis by Kaplan-Meier revealed a significant association between high expression (>50%) of p16INK4a in tumours and better disease-specific survival (p=0.03, log-rank test). Cox regression analysis showed that p16INK4a expression is an independent covariate in disease-specific survival (p<0.01). CONCLUSIONS: The absence of p16INK4a expression in most tumour cells indicates that p16INK4a could be involved in the tumourigenesis of RCC. Immunohistochemically detected positivity for p16INK4a is a positive prognosticator for specific survival in both uni- and multivariate analyses.     

结直肠癌p16/MTS1基因纯合缺失的研究

目的 探讨p16/MTS1基因结合缺失与结直肠癌的发生及临床病理关系.方法 采用聚合酶链反应方法,对68例结直肠癌组织中p16/MTS1基因纯合缺失进行检测.并用Fisher精确检验的方法,对p16/MTS1基因纯合缺失与临床病理关系进行统计分析.结果 68例结直肠癌组织,p16/MTS1基因纯合缺失率为35.29%.Duekes C、D期的缺失率明显高于Duckes A、B期(P<0.05).低分化腺癌p16/MTS1基因纯合缺失率(11/16)高于高分化腺癌肿瘤(4/25)(P<0.05).侵犯到浆膜及浆膜外者p16/MTS1基因纯合缺失率高于侵犯在浆膜内者(P<0.05).结论 p16/MTS1基因纯合缺失与结直肠癌的临床分期、病理分化、肌层浸润等生物学特征有关.     

p16(INK4a) alterations in chronic pancreatitis-indicator for high-risk lesions for pancreatic cancer

BACKGROUND. p16(INK4a) alterations are considered to be an early event in pancreatic tumorigenesis and have been described in duct lesions adjacent to pancreatic cancers. This study evaluates whether duct lesions in chronic pancreatitis tissues of patients without pancreatic cancer also harbor genetic alterations in the p16(INK4a) tumor-suppressor gene, and thus represent high-risk precursors for pancreatic cancer. METHODS. Tissues were obtained from 20 pancreatic specimens taken from patients operated on for histologically verified chronic pancreatitis. Pancreatic intraductal neoplasias (PanIN) were identified in hematoxylin-and-eosin-stained slides. p16 protein expression was investigated immunohistochemically in all specimens. DNA from PanIN and non-PanIN tissue was analyzed genetically for p16(INK4a) mutations by single-strand conformation variation analysis and direct sequencing of the encoding region. Additionally, p16(INK4a) promoter methylation was analyzed by a methylation specific polymerase test. RESULTS. PanIN-1a lesions were identified in 10 of the 20 chronic pancreatitis specimens. Four of these 10 PanIN specimens (40%), but none of the 20 non-PanIN tissues, revealed a loss of p16 expression in immunohistochemistry. The mutational analysis of the p16(INK4a) gene showed 1 known polymorphism (c.442G > A; A148T) but no mutations. Two of the 10 specimens with PanIN revealed an inactivating hypermethylation of the p16(INK4a) promoter. CONCLUSIONS. This study shows for the first time that p16(INK4a) alterations can be observed in a considerable number of PanIN1 in chronic pancreatitis tissues not associated with pancreatic cancer. Therefore, p16(INK4a) alterations, especially promoter methylation, might indicate high-risk precursors in chronic pancreatitis that might progress to cancer.     

Aneuploidy of chromosome 9 and the tumor suppressor genes p16(INK4) and p15(INK4B) detected by in situ hybridization in locally advanced prostate cancer

INTRODUCTION AND OBJECTIVES: The linked p16(INK4)/MTS1 and p15(INK4B)/MTS2 genes on chromosome 9p21 encode proteins that inhibit the cyclinD dependent kinases CDK4/6. Biallelic homozygous deletions involving this locus have been identified in a wide range of tumor cell lines, but in a lower frequency of primary tumors. As PCR based approaches analyzing for homozygous deletions could be confounded by unavoidable contributions of normal cells in microdissected tissue, we performed in situ hybridization (ISH) on primary prostate carcinomas to accurately evaluate p16 and p15 copy numbers on a cell-by-cell basis. MATERIAL AND METHODS: p16 and p15 loci were evaluated in 28 pT3N0M0 prostate cancer specimens. Of 28 patients, 15 (53%) were ascertained showing no recurrence (mean follow-up 61+/-17 months), 13 (47%) developed recurrences within 27+/-19 months. Tissues were provided for ISH analysis in a blinded fashion. Isolated DNA derived from P1 clone 1063 compromising p16 and p15 as well as a centromeric probe for chromosome 9 were used for hybridization. Signals were enumerated within 300 interphase nuclei per tumor specimen, and in 100 nuclei derived from 18 benign prostate tissues and 7 adjacent PIN regions. RESULTS: ISH detected aneuploid tumors in 12/13 (92%) patients with recurrence and in 5/15 (33%) without recurrence (p<0.0014). Whereas 3/7 PIN specimens associated with nonrecurrent PCA demonstrated euploidy, all 4/7 PIN associated with recurrent disease demonstrated the same aneuploidy for chr9 as the primary tumor. All benign tissues evaluated exhibited euploidy for chr9, p16 and p15. None of the PCA and PIN samples revealed homozygous deletions for p16(INK4)/MTS1/p15(INK4B)/MTS2; 2/28 (7.1%) PCA exhibited partial deletion for p16(INK4)/MTS1/p15(INK4B)/MTS2 and aneuploidy for chr9; both PCA derived from the recurrent group. CONCLUSIONS: Deletion of 9p21 was rare and therefore such genetic alterations may not play an important role in the pathogenesis of PCA. Analysis of the limited number of PCA examined suggest a strong association between chr9 aneuploidy and recurrenct disease. Aneuploidy in both PIN and PCA suggests that the clinical outcome of PCA might already be determined in the preinvasive PIN.     

肝硬化组织中p16INK4a和Rb的基因甲基化状态和蛋白表达

目的：探讨肝硬化组织中p16INK4a和视网膜母细胞瘤易感基因（Rb基因）启动子区域的甲基化状态与其蛋白的表达的关系。方法：分别采用PCR和免疫组织化学方法测定65例肝硬化患者和20例正常人肝组织中p16INK4a和Rb启动子区域甲基化状况和蛋白的表达。结果：20例正常肝组织（对照组肝组织）中均未检测到p16INK4a和Rb甲基化异常,肝硬化组肝组织中p16INK4a和Rb基因甲基化率分别为40.0%（26/65）和36.9%（24/65）;p16INK4a和Rb蛋白表达的积分光密度（IOD）在正常肝组织为225.7±27.4和254.7±34.8,在肝硬化组肝组织中为32.4±7.5和45.2±6.4,差异均有统计学意义（均P<0.05）。结论：肝硬化组织中存在p16INK4a和Rb异常甲基化和p16INK4a和Rb蛋白的表达降低,由此导致的细胞周期失控可能参与了肝硬化的发生发展过程。     

The 9p21 region in bladder cancer cell lines: large homozygous deletions inactivate the CDKN2, CDKN2B and MTAP genes

Homozygous and hemizygous deletions of 9p21 are the earliest and most common genetic alteration in bladder cancer. The identification of two cell cycle regulators, CDKN2 and CDKN2B, that map to the common region of deletion has prompted the hypothesis that they are critical tumor suppressor genes in this malignancy. However, controversy as to whether these genes are the only or even the most important target in bladder cancer oncogenesis remains. To more clearly determine the effect of these 9p21 alterations, we mapped the homozygous deletions and performed a detailed mutational and expression analysis for CDKN2, CDKN2B and a closely linked gene, methylthioadenoside phosphorylase (MTAP), in 16 established bladder cancer cell lines. Nine of the 16 lines exhibit large (30 to >2000 kb) homozygous deletions on 9p21. All deletions include at least one exon of CDKN2, eight of nine include CDKN2B, and six of nine include MTAP. MTAP function correlates with the genomic deletions. SSCP and sequence analysis does not reveal any inactivating point mutations of CDKN2 or of CDKN2B in any of the cell lines without homozygous deletions, and all express the CDKN2 and the CDKN2B mRNA as well as the encoded p16 protein. The p16 protein levels vary widely and are correlated with absent pRb expression. We conclude that the 9p21 deletions in bladder cancer usually inactivate the CDKN2, CDKN2B, and MTAP genes but that CDKN2 is the most common target. Other mechanisms for inactivating this gene in bladder cancer appear to be uncommon.     

Expression of p19INK4d, CDK4, CDK6 in glioblastoma multiforme

Deregulation of the G1/S checkpoint is a frequent event in the development of glioblastoma multiforme (GBM). Previous studies have shown more than 50% of primary GBM tumours contain either complete loss of the p16INK4a locus or amplification of the CDK4 gene. Moreover, many heterozygosity studies have shown deletion on human chromosome 19p13.2, where the p19INK4d gene has been localized. We examined the expression of p19INK4d and its two CDK substrates in a series of glioma-derived cell lines and tumours. No gene rearrangement or deletion was observed in the p19INK4d gene in these cell lines; however, expression of CDK4 and CDK6 was elevated relative to matched normal brain tissue in eight of 18 GBM tumours (44%). Furthermore, CDK6 expression level was increased in 12/14 glioblastomas, but undetectable in tumour samples of a previous lower grade tumour from the same patient. These data attest to the functional importance of both CDK4 and CDK6 in astrocytic tumourigenesis, particularly during the later stages of tumour progression.     

Analysis of homozygous deletion of the p16 gene and correlation with survival in patients with glioblastoma multiforme

OBJECT: One of the most frequent genetic abnormalities found in patients with glioblastoma multiforme (GBM) is homozygous deletion of the p16 tumor suppressor gene. The authors investigated whether this deletion is associated with prognosis in patients with GBM. METHODS: In 46 adult patients with supratentorial GBM, homozygous deletion of the p16 gene in tumor DNA was examined using the multiplex polymerase chain reaction assay. The deletion was confirmed in 14 (30.4%) of 46 patients, eight (30.8%) of 26 men and six (30.0%) of 20 women. Cox proportional hazard regression analysis, adjusted for age at surgery, the Karnofsky Performance Scale score, extent of resection, and the MIB-1 labeling index. revealed that homozygous deletion of the p16 gene was significantly associated with overall survival and progression-free survival in men, but not in women. CONCLUSIONS: The results of this study suggest that p16 homozygous deletion is a significant unfavorable prognostic factor in male patients with GBM.     

p16和nm23-H1基因表达与胃癌及淋巴结转移的关系

目的:进一步评估p16和nm23鄄H1基因表达在胃癌中的作用,尤其是与肿瘤淋巴结转移的关系。方法:采用免疫组织化学方法,检测p16和nm23鄄H1基因蛋白在46例原发性胃癌及69枚转移淋巴结中的表达,探索二者表达与胃癌临床病理特征的关系,评估二者作为预测肿瘤转移和临床预后的生物学指标的可能性。结果:p16和nm23鄄H1基因蛋白表达在原发性胃癌中的阳性率分别为17.4%和28.3%,在转移淋巴结中的阳性率分别为15.9%和14.5%。p16表达在伴和不伴淋巴结转移的原发性胃癌中差异显著(P<0.05)。nm23鄄H1在乳头状腺癌中呈明显高表达。p16和nm23鄄H1蛋白表达在原发性胃癌及转移淋巴结中无相关关系。结论:胃癌组织和转移淋巴结中存在p16和nm23鄄H1基因蛋白频繁缺失;p16阳性表达的病人淋巴结转移机会降低;nm23鄄H1基因蛋白表达率在乳头状腺癌中明显高于其他组织学类型;nm23鄄H1表达与胃癌淋巴结转移无关;p16和nm23鄄H1表达调节似无关联,同时检测p16和nm23鄄H1表达不比单纯检测p16表达具有更高预测胃癌淋巴结转移的价值。