bcl-2、p53在皮肤肿瘤中的表达及意义

目的探讨bcl-2、p53在几种皮肤肿瘤中的表达及意义。方法采用流式细胞术(FCM)和免疫荧光技术对皮肤鳞状细胞癌(SCC)、恶性黑色素瘤(MM)、基底细胞癌(BCC)、色素痣(PN)bcl-2、p53蛋白的表达进行定量分析,以荧光指数(FI)作为定量表达指标。结果鳞状细胞癌、基底细胞癌的bcl-2、p53基因蛋白的FI值均显著性高于正常对照(P<0.05),基底细胞癌的bcl-2基因的FI值显著性高于鳞状细胞癌(P<0.05),而二者的p53基因蛋白的FI值无显著性差异(P>0.05);恶性黑色素瘤、色素痣的bcl-2、p53基因蛋白的FI值均显著性高于正常对照(P<0.05),恶性黑色素瘤的p53基因的FI值显著性高于色素痣(P<0.05),而二者的bcl-2基因蛋白的FI值无显著性差异(P>0.05)。结论鳞状细胞癌、恶性黑色素瘤、基底细胞癌、色素痣中均有bcl-2的表达,基底细胞癌bcl-2表达显著高于鳞状细胞癌,说明基底细胞癌的发生发展可能与细胞凋亡受抑密切相关;p53在恶性黑色素瘤的表达高于色素痣,说明p53为黑色素瘤的恶性标志,检测p53表达可以作为鉴别皮肤黑色素瘤恶性病变的辅助手段。     

幽门螺杆菌感染对胃黏膜细胞hMSH2,hMLH1和p53基因表达的影响(英文)

目的探讨幽门螺杆菌(Helicobacter pylori,H.pylori)感染与胃癌、癌旁及胃炎黏膜中 hMSH2,hMLH1和 p53基因表达的关系,进一步了解 H.pylori 在胃癌发生中的作用。方法采用快速尿素酶方法检测 H.pylori;采用免疫组化 SP 法检测 hMSH2,hMLH1和 p53基因表达。结果 (1)hMSH2在胃癌中的表达阳性率(62.7%)显著高于癌旁(29.4%),胃炎黏膜(32.4%)和正常对照(30.0%)(P<0.001)。其中在低分化腺癌中阳性率(76.4%)显著高于高中分化腺癌(54.3%)和黏液癌(53.1%)(P<0.05);hMLH1在胃癌中的表达阳性率(64.3%)显著低于癌旁(84.4%),胃炎黏膜(82.4%)和正常对照(80.0%)(P<0.01)。其中在黏液癌的阳性率(43.7%)显著低于其他两种腺癌(78.2%,64.7%)(P<0.01);p53在胃癌中的表达阳性率(51.9%)显著高于癌旁(3.1%),胃炎黏膜(0.0%)和正常对照(0.0%)(P<0.001)。其中,在高中分化腺癌的阳性率(32.6%)显著低于黏液癌(68.7%)和低分化腺癌(58.8%)(p<0.05)。(2)在全部被检组织中,H.pylori 感染组 hMSH2和 hMLH1的表达阳性率均低于相应的非感染组。其中,胃癌 H.pylori感染组 hMSH2的表达阳性率(52.8%)显著低于非感染组(74.5%)(P<0.05)。胃癌 H.pylori 感染组 p53的表达阳性率(61.4%)显著高于非感染组(40.6%)(P<0.05)。结论胃癌的发生发展可能与 hMSH2,hMLH1和 p53基因的异常表达有关;H pylori 感染影响这三种基因的正常表达,这可能是H.pylori 致癌的机制之一。     

Loss of hMSH2 expression in primary breast cancer with p53 alterations

Inactivation of DNA mismatch repair genes (MRG) is a recently described pathway of cancer development and progression resulting in genetic instability. Germline mutations in MRG have been studied predominantly in patients with hereditary non-polyposis colorectal cancer (HNPCC) where it is associated with microsatellite instability (MSI). The expression of MRG in primary breast cancer is still largely unexplored. The hMSH2 MRG encodes a protein that recognizes and binds to mismatch sequences of DNA. We investigated the relation-ship between hMSH2 expression and clinicopathological and biological characteristics, including p53 and p185 expression, in 44 primary invasive breast cancers. hMSH2 was not expressed in 11 cases (25%). Interestingly, p53 (p=0.05), p185 and steroidal receptor expression (p=0.07) were more frequent in tumors without hMSH2 expression. Furthermore, in 30 of 44 cases we analyzed hMSH2 expression in relation to MSI at 9 dinucleotide loci, and found that MRG expression was not significantly related to MSI. The presence of hMSH2 and p53 alterations in the same tumor suggests that the two oncoproteins act through a common mutational pathway, whereas the absence of a correlation between hMSH2 and MSI suggests that oncogenetic mechanisms of progression in primary breast cancer differ from those in HNPCC.     

幽门螺杆菌感染对胃黏膜细胞hMSH2,hMLH1和p53基因表达的影响

目的探讨幽门螺杆菌(Helicobacterpylori,H.pylon)感染与胃癌、癌旁及胃炎黏膜中hMSH2,hMLH1和p53基因表达的关系,进一步了解H.pylori在胃癌发生中的作用。方法采用快速尿素酶方法检测H.pylori;采用免疫组化SP法检测hMSH2,hMLH1和p53基因表达。结果(1)hMSH2在胃癌中的表达阳性率(62.7%)显著高于癌旁(29.4%),胃炎黏膜(32.4%)和正常对照(30.0%)(P<0.001)。其中在低分化腺癌中阳性率(76.4%)显著高于高中分化腺癌(54.3%)和黏液癌(53.1%)(P<0.05);hMLH1在胃癌中的表达阳性率(64.3%)显著低于癌旁(84.4%),胃炎黏膜(82.4%)和正常对照(80.0%)(P<0.01)。其中在黏液癌的阳性率(43.7%)显著低于其他两种腺癌(78.2%,64.7%)(P<0.01);p53在胃癌中的表达阳性率(51.9%)显著高于癌旁(3.1%),胃炎黏膜(0.0%)和正常对照(0.0%)(P<0.001)。其中,在高中分化腺癌的阳性率(32.6%)显著低于黏液癌(68.7%)和低分化腺癌(58.8%)(P<0.05)。(2)在全部被检组织中,H.pylori感染组hMSH2和hMLH1的表达阳性率均低于相应的非感染组。其中,胃癌H.pylori感染组hMSH2的表达阳性率(52.8%)显著低于非感染组(74.5%)(P<0.05)。胃癌H.pylori感染组p53的表达阳性率(61.4%)显著高于非感染组(40.6%)(P<0.05)。结论胃癌的发生发展可能与hMSH2,hMLH1和p53基因的异常表达有关;H.pylori感染影响这三种基因的正常表达,这可能是H.pylori致癌的机制之一。     

Cisplatin fails to induce puma mediated apoptosis in mucosal melanomas

Objectives

Mucosal melanomas (MM) are aggressive subtypes of common melanomas. It remains unclear whether limitations in their resectability or their distinctive molecular mechanisms are responsible for the aggressive phenotype.

Methods

In total, 112 patients with cutaneous melanomas (CM) and 27 patients with MM were included. Clinical parameters were analysed using Chi square, Fisher exact and student''s t-test. Survival rates were calculated by Kaplan–Meier. Analysis of p53, p21, Mdm2, Hipk2, Gadd45, Puma, Bax, Casp9 and Cdk1 via quantitative PCR and immunohistochemistry (IHC) was performed. TP53 induction after cisplatin treatment was analysed in 10 cell lines (melanocytes, four MM and five CM) using western blot (WB) and qPCR.

Results

The overall/recurrence-free survival differed significantly between MM (40 months and 30 months) and CM (90 months and 107 months; p < 0.001). IHC and WB confirmed high p53 expression in all melanomas. Hipk2 and Gadd45 showed significantly higher expressions in CM (p < 0.005; p = 0.004). QPCR and WB of wild-type cell lines demonstrated no differences for p53, p21, Mdm2, Bax and Casp9. WB failed to detect Puma in MM, while Cdk1 regulation occurred exclusively in MM.

Conclusions

The aggressive phenotype of MM did not appear to be due to differential expressions of p53, p21, Mdm2, Bax or Casp9. A non-functional apoptosis in MM may have further clinical implications.     

子宫颈癌错配修复基因产物与p53表达

[目的]探讨子宫颈癌中错配修复基因表达产物对抑癌基因p53表达的影响.[方法]30例子宫颈炎标本及70例子宫颈鳞癌标本采用免疫组织化学S-P法检测hMLH1、hMSH2与p53的表达.[结果]子宫颈炎与子宫颈鳞癌组织hMLH1阳性表达率分别为60.0%（18/30）与55.7%（39/70）;hMSH2阳性表达率分别为23.3%（7/30）与57.1%（40/70）;p53表达率分别为33.3%（10/30）与61.4%（43/70）.p53表达阳性和阴性组的子宫颈癌hMLH1阳性表达率分别为46.5%（20/43）与40.7%（11/27）,两者无相关性（rs=0.057,P=0.645）;hMSH2阳性表达率分别为41.9%（18/43）与18.5%（5/27）,两者存在显著相关性（rs=0.242,P=0.044）.[结论]子宫颈炎向宫颈癌的发展中碱基错配逐渐增多,hMSH2蛋白的高表达与p53的低表达对宫颈癌的预后具有一定的预测作用.     

High thymidylate synthase expression in colorectal cancer with microsatellite instability: implications for chemotherapeutic strategies.

Colon cancers displaying microsatellite instability (MSI) are clinically less aggressive. Based on in vitro studies and recent clinical data, cancers displaying MSI do not respond to 5-fluorouracil (5-FU). The reasons why MSI tumors are clinically less aggressive and do not respond to 5-FU-based therapies have not been fully elucidated. PURPOSE: We investigated biomolecular markers in an attempt to explain the different clinical behavior and chemotherapeutic responses of MSI and non-MSI colon cancers. EXPERIMENTAL DESIGN: One hundred ninety-two sporadic colon cancers were tested for MSI with five mononucleotide markers and methylation of the hMLH1 promoter. Slides were stained for thymidylate synthase (TS), p53, MDM2, p21(WAF1/CIP1), beta-catenin, vascular endothelial growth factor, hMLH1, hMSH2, and hMSH6. Tumors were regarded as having wild-type, functional p53 (Fp53) if reduced expression of p53 and positive MDM2 and p21(WAF1/CIP1) expressions were found. RESULTS: Of the cases, 12.5% were MSI-H (at least two markers mutated). Of MSI-H cases, 83.3% were characterized by a complete loss of at least one of the mismatch repair proteins, in particular loss of hMLH1 by promoter hypermethylation. MSI-H colon cancers showed higher expression of TS compared with MSS (no mutated markers)/MSI-L (one mutated marker) colon cancers (66.6% for MSI-H versus 14.8% MSS/MSI-L; P < 0.0001); 20.8% of MSI-H cases showed high expression of the vascular endothelial growth factor, compared with 45.8% MSS/MSI-L colon cancers (P = 0.0005); 45.8% MSI-H cases had Fp53 compared 11.9% MSS/MSI-L cases (P < 0.0001). CONCLUSIONS: About 12% of colon cancers display MSI mostly due to lack of hMLH1 resulting from promoter hypermethylation. These tumors have high expression of TS and retain fully functional p53 system. Thus, these data suggest why sporadic hMLH1-defective colon cancers often do not respond to 5-FU.     

胃癌中hMSH2、p53和PCNA表达的相关性及意义

目的:探讨胃癌中hMSH2、p53和PCNA表达的相关性及意义.方法:采用免疫组织化学SP法,检测胃癌、癌旁和胃炎粘膜中hMSH2、p53和PCNA表达情况.结果:1)3种基因产物在胃癌中的阳性率均显著高于非癌组织,其中,p53和PCNA在低分化癌中的阳性率显著高于高分化癌,有淋巴结转移者显著高于无转移者(P＜0.05).2)胃癌中hMSH2/PCNA及p53/PCNA表达均呈正相关(P＜0.05).结论:hMSH2、p53和.PCNA的异常表达及hMSH2与PCNA之间的相互调节可能与胃癌的发生发展密切相关.     

Alterations of p53, Bcl-2, and hMSH2 protein expression in the normal breast, benign proliferative breast disease, in situ and infiltrating ductal breast carcinomas in the upper Egypt

BACKGROUND: Tumorigenesis involves alterations in the tumor suppressor genes (p53), protooncogenes (Bcl-2) and housekeeping genes [human MutS homologue-2 (hMSH2)]. We hypothesized that mammary carcinogenesis involves interactions among p53, Bcl-2 and hMSh2 proteins. In the Upper Egypt, the clinicopathologic features and genetic changes during mammary carcinogenesis are unknown. METHODS: To test our hypothesis and to examine these issues, 53 mastectomy specimens, each entailing normal breast, benign proliferative breast disease (BPBD), duct carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC) were immunostained for p53, Bcl-2 and hMSH2 protein expression. RESULTS: The average age incidence of ductal carcinomas was 43.2 +/- 7.06 years. The tumors were common in the left than right side (1.2:1, respectively, p > 0.05). Infiltrating ductal carcinoma of non-specific type was the most common histologic type. Examination of the average weighted scores in the normal breast, BPBD, DCIS and IDC, respectively, showed: (1) significant upregulation of p53 proteins (0.00 +/- 0.00, 0.00 +/- 0.00, 6.25 +/- 2.42, 6.62 +/- 2.15, p = 0.001), (2) insignificant downregulation of Bcl-2 (6.67 +/- 1.33, 5.17 +/- 2.20, 4.79 +/- 2.27 and 4.42 +/- 2.83, p = 0.37), and (3) significant downregulation of hMSH2 (11.3 +/- 0.75, 10.70 +/- 1.27, 7.11 +/- 1.50 and 7.0 +/- 1.33, p = 0.0006). There were insignificant negative correlations between p53 and both Bcl-2 (r = -0.20, p > 0.05) and hMSH2 (r = -0.15, p > 0.05) protein expression. CONCLUSIONS: In the Upper Egypt: (1) breast cancer had similar clinicopathologic features to those in the high risk regions, and (2) alterations of the p53, Bcl-2 and hMSH2 proteins occur during mammary carcinogenesis.     

Differential expression of hMLH1 and hMSH2 is related to bladder cancer grade,stage and prognosis but not microsatellite instability

Defects in the DNA mismatch repair proteins result in microsatellite instability and malignancy in hereditary non-polyposis colorectal carcinoma (HNPCC). However, the role of mismatch repair (MMR) proteins and microsatellite instability (MSI) in transitional cell carcinoma of the bladder is less clear. In our study, the expression of 2 MMR proteins and the frequency of MSI in Transitional cell carcinoma of the bladder (TCC) were investigated. One hundred eleven patients with TCC of the bladder were studied, with complete clinicopathological data (median follow up of 5 years, range 5-16 years). Immunohistochemistry was used to detect the expression levels of hMLH1 and hMSH2. Microsatellite analysis for 14 loci (10 loci from the Bethesda consensus panel and the repeats in the TGFbetaR2, BAX, hMSH3 and hMSH6 genes) was performed on 84 tumors. Reduced expression of either MMR protein was seen in 26 of 111 tumors (23%). Reduced expression was seen more commonly in muscle invasive (p<0.03) and high grade TCC (p<0.03) than in superficial, low grade tumors. By 5 years, reduced expression of either MMR protein was associated with fewer recurrences of superficial tumors (p=0.015) and fewer relapses in all tumors (p=0.03), compared to tumors with normal expression. Nine tumors had reduced expression of both MMR proteins, analysis which suggests a synergistic reduction in expression (p=0.001). MMR expression was related to patient age, younger patients being more likely to have reduced MMR expression than older patients (p<0.01). MSI was seen at multiple loci in 1 tumor (1%) and at a single locus in 6 tumors (7%). MSI was not associated with MMR expression. Our findings indicate that reduced expression of the MMR proteins may have an important contribution in the development of a subset of TCCs and suggest a potential role for MMR expression as prognostic indicators.     

Immunoexpression of p53 and hMSH2 in oral squamous cell carcinoma and oral dysplastic lesions in Yemen: relationship to oral risk habits and prognostic factors

Although several studies analyzed p53 and mismatch repair (MMR) gene expression separately in oral squamous cell carcinoma (SCC), no reports of combined assessment of both proteins in this cancer. The aim of this study was to investigate the roles of p53 and hMSH2 proteins in oral SCC as well as in oral dysplastic lesions (DL) in Yemen. Immunohistochemistry was used to examine the pattern of expression of p53 and hmsh2 proteins in 70 oral SCC and 21 oral DL obtained from Yemeni patients. p53 Immunoexpression was detected in 24 of the 70 oral SCC (34.3%) and 3 of 21 DL (14.3%) with no significant difference between the two groups. On the other hand, reduced expression of hMSH2 was detected in 26 of the 70 oral SCC (37.1%) and 2 of 21 oral DL (9.5%) with a statistically significant difference (P=0.03). Both proteins were significantly related to the grade of tumor differentiation (P=0.007 and 0.02, respectively). There was an inverse correlation between the levels of p53 and hMSH2 immunoexpression in the oral SCC (r=0.42, P=0.01). This study suggested that p53 may play a role in the early stages of oral carcinogenesis, while hMSH2 may be altered in the late stages. More importantly, the roles of p53 and hMSH2 in oral carcinogenesis seem to be interrelated in the pathogenetic pathway of oral SCC. Such a relationship has not been published previously in this type of cancer and needs to be clarified in future studies.     

Prognosis in patients with hepatocellular carcinoma correlates to mutations of p53 and/or hMSH2 genes

Association of gene alterations and prognosis has not fully been elucidated in hepatocellular carcinoma (HCC). To clarify the relationship between p53 and hMSH2 mutations and prognosis, we analysed these mutations in 83 HCC cases and assessed their association with various clinicopathological factors. The 3-year disease-free survival (DFS) or overall survival (OS) rates in HCC patients with p53 mutation and p53 wild/hMSH2 mutation significantly decreased compared with those without these mutations (14.3% and 37.5% versus 67.5% for DFS; 35.7% and 50.0% versus 96.4% for OS, respectively). In the multivariate analysis, categories by p53 and hMSH2 mutation status, and liver cirrhosis demonstrated statistical significances for DFS and OS. Moreover, the frequency of patients with p53 and/or hMSH2 mutations in intrahepatic metastasis (75.0%) was significantly higher than that in multicentric occurrence (14.3%). Thus, p53 and hMSH2 mutations will be useful for identifying subsets of HCC patients with poor prognosis.     

Microsatellite status and immunohistochemical features of ovarian clear-cell carcinoma

BACKGROUND: Ovarian clear-cell carcinoma (OCC) is known to have a poor prognosis and selected genetic features of OCC remain unknown. We investigated microsatellite instability (MSI) and the expression of the DNA mismatch repair-related protein, p53. MATERIALS AND METHODS: MSI was examined by polymerase chain reaction using mono-, di-, tri- and tetranucleotide repeat markers, and hMSH2, hMLH1, hMSH6, MSH3 and p53 were determined immunohistochemically in 24 cases of OCC. RESULTS: A total of 9 (37.5%) cases exhibited MSI. Two cases (8.3%) exhibited MSI-H in mononucleotide repeat loci with the negative expression of hMLH1, while another 7 cases (29.2%) exhibited selected trinucloetide repeat MSI (MSI-TR). Of these MSI-TR cases, 4 cases (57.1%) were determined to be negative for MSH3, while hMSH2, hMSH6, MSH3 and p53 expressions were normal. CONCLUSION: Our findings suggest that MSI-TR would be a feature indicating the microsatellite status in OCC, and that the loss of MSH3 expression may promote MSI-TR.     

Close correlation between a p53 or hMSH2 gene mutation in the tumor and survival of hepatocellular carcinoma patients

We analyzed 42 hepatocellular carcinomas (HCC) (38 patients) for mutations in the DNA mismatch repair gene hMSH2 and the p53 tumor suppressor gene, a possible upregulater of hMSH2. Mutations of the hMSH2 or p53 gene were detected in 13 patients (34%). There were no patients who possessed mutations in both genes. There was a significant correlation between mutation of either gene and pathological indicators of malignancy. The survival rate of patients with hMSH2 or p53 gene mutation-positive tumors was much poorer than that with hMSH2 and p53 gene mutation-negative tumors (p=0.0012). Our results suggest that mutations in the p53 or hMSH2 gene may closely correlate with the survival of hepatocellular carcinoma patients.     

The role of TP53 and MDM2 polymorphisms in TP53 mutagenesis and risk of non-melanoma skin cancer

P53 is a key regulatory molecule in the cellular response to ultraviolet radiation, and TP53 mutation is the most common alteration in non-melanoma skin cancer. The MDM2 oncogene negatively regulates p53 protein levels, and both genes have functional polymorphisms that may modify skin cancer risk. Furthermore, prior research suggests that TP53 mutations preferentially occur on the arginine allele to selectively inactivate the p63 pathway. We tested these hypotheses of susceptibility and preferential mutation in non-melanoma skin cancer. The TP53 Arg72Pro and MDM2 309 polymorphisms were genotyped in a population-based case-control study of non-melanoma skin cancer, and TP53 alteration (mutation and immunohistochemistry staining) was evaluated in case tumors. In 902 cases of basal cell carcinoma (BCC), 676 cases of squamous cell carcinoma (SCC) and 812 controls, no association was found between the TP53 polymorphism and risk of non-melanoma skin cancer [odds ratio (OR)(BCC) 0.98, 95% confidence interval (CI) 0.80-1.20; OR(SCC) 0.93, 95% CI 0.75-1.16]. However, carriers of the MDM2 SNP309 G allele did have an elevated risk of non-melanoma skin cancer (OR(BCC) 1.15, 95% CI 0.93-1.42; OR(SCC) 1.29, 95% CI 1.02-1.63). We observed an association between TP53 alterations in the tumors and constitutive TP53 genotype (P < 0.01), with alterations preferentially occurring on the proline allele. Collectively, these data highlight the significant effects of genotype on gene-specific mutation events in carcinogenesis.     

Immunohistochemistry of proteins for DNA mismatch repair in correlation to prognostic factors of mammarian cancer

Mutations in genes of the DNA mismatch repair system (MMR) are strongly linked to the development of hereditary non-polyposis colorectal cancer and play a significant role in sporadic cancer too. Besides the repair of chromosomal mismatches produced during replication, the MMR is the linkage of DNA mismatches to cell cycle control. Proteins of the MMR are necessary for the induction of apoptosis in response to non-tolerable amounts of DNA damage. We correlated the immunoreactivity of the MMR proteins hMSH2, hMLH1 and PMS2 to the immunoreaction of p53, the proliferation marker Ki67 and clinical prognosis factors such as tumor grading and staging, steroid receptor expression and hemangiosis carcinomatosa or lymphangiosis carcinomatosa in 200 samples from patients with diagnosed breast cancer. No correlation could be detected among the expression of the three MMR-proteins hMSH2, hMLH1 and PMS2. The expression of hMSH2 correlated positively with the expression of p53, with the appearance of distant metastases, low differentiation and the appearance of hemangiosis carcinomatosa and lymphangiosis carcinomatosa, while it negatively correlated with the expression of the estrogen receptor. No correlation was detected between hMLH1 or PMS2 and any of the investigated factors. The expression of hMSH2 seems to be related with predictors of an unfavorable course of disease in breast cancer.     

Combined deficiency of hMLH1, hMSH2, hMSH3 and hMSH6 is an independent prognostic factor in colorectal cancer

We examined biological and clinicopathological significance of individual and combined hMLH1, hMSH2, hMSH3 and hMSH6 expression with immunohistochemistry in 301 unselected colorectal cancers. Weak hMLH1 expression was correlated to microsatellite instability (P=0.04), negative p53 expression (P=0.005) and mucinous carcinomas (P=0.02). Weak hMSH2 expression was related to negative ras (P<0.001) and p53 expression (P=0.005), and better survival (P=0.03). hMSH2, hMSH3 and hMSH6, as well as hMLH1, hMSH2, hMSH3 and hMSH6, were combined into a 'functional' and a 'less-functional' group, respectively. Both 'less-functional' groups were/tended to be associated with microsatellite instability, negative ras and p53 expression, and better survival. In summary, hMLH1 and hMSH2 were more important when investigated individually, and the combined groups were more related to the mutator pathway, suggesting that combined deficiencies of the proteins are more efficiently involved in the mutator pathway. Our result from weak versus strong staining may suggest that the intensity of staining should be considered in future studies on mismatch repair proteins.     

Missense mutation of the hMSH6 and p53 genes in sporadic urothelial transitional cell carcinoma

Functional defects in DNA mismatch repair genes have been shown to be associated mainly with hereditary human malignancies. We examined genomic DNA from 88 sporadic transitional cell carcinomas (TCCs) of the urinary tract for mutations in hMSH6 gene by polymerase chain reaction and direct sequencing analysis. Mutational status of p53 gene was also studied as a potential target of genetic instability secondary to hMSH6 dysfunction. A total of 5 cases (5.7%: 5/88) displayed hMSH6 mutations all consisted of transition and located in exon 4, including three cases with missense mutation and two without change of corresponding amino acid. These three tumors with hMSH6 missense mutation had no microsatellite instability with five microsatellite markers tested. p53 gene mutations were detected in 22 cases (25.0%: 22/88). No tumors with p53 mutation had any hMSH6 missense mutations. Compared to the cases without hMSH6 alterations, the three patients with hMSH6 alterations had more frequent additional primary cancer (P<0.05). These findings provide the first in vivo evidence for the type of alterations and frequency of possible involvement of the hMSH6 mutations in sporadic type urothelial TCCs.     

Immunohistochemical analysis of bcl-2 and p53 protein in breast carcinoma

We analyzed the expression of bcl-2 and p53 in relation to clinicopathological features and estrogen receptor (ER) status in breast carcinomas from a series of 67 women who were treated surgically. Fifty and 23 cases showed positive immunostaining for bcl-2 and p53 protein, respectively. Thirty-five cases were ER-positive. A positive relationship was observed between bcl-2 and ER (p<0.05). Furthermore, an inverse relationship was observed between bcl-2 and p53 (p<0.01), which suggests that overexpression of p53 may down-regulate bcl-2 expression in breast carcinoma tissue, as has been described in a breast carcinoma cell line.