Genetic alterations in p53 and k-ras in lung-cancer in relation to histopathology of the tumor and smoking history of the patient

The inactivation of the p53 suppressor gene and the activation of the ras proto-oncogenes are frequent events in non-small cell lung cancer as well as in many other solid neoplasms in man. Somatic mutations in exons 5-8 of the p53 gene were detected in 59% (30/51) of the squamous cell carcinoma and in 38% (14/37) of the adenocarcinoma tumors using GC-clamped, non-radioactive denaturing gradient gel electrophoresis (DGGE). The mutations in the exons 5 and 8 represented larger proportion of the alterations in squamous cell carcinoma tumors (p=0.04; Fisher's exact test, two-tailed); in the adenocarcinoma tumors, mutations were most common in the exon 7 of p53. Most of the identified mutations (25/39; 64%) are predicted to cause an amino acid substitution. Mutations leading to the premature termination of translation were more frequent in adenocarcinoma (6/14) than in squamous cell carcinoma (3/30) tumors (p=0.02). In adenocarcinoma, also base substitutions in the K-ras gene were detected more often (18/37; 49%) than in squamous cell carcinoma (p<0.01). However, a mutation both in p53 and Kras was detected in only 4% of the lung tumors which does not support importance of co-operation between the genes in vivo. Mutations in p53 and K-ras did not correlate with tumor differentiation in either histological type. In squamous cell carcinoma, mutations in p53 showed relation to pack years smoked whereas in adenocarcinoma, mutations in the K-ras gene were associated with cigarette consumption. G to T transversion was the most common type of base substitution in both genes (31% in p53 and 53% in K-ras).     

Mutations of p53 in morphologically non-neoplastic mucosa of long-standing ulcerative colitis.

Two cases of ulcerative colitis (UC)-associated carcinoma or dysplasia and morphologically non-neoplastic mucosa with p53 protein overexpression (MNNM-p53OE) were selected. DNA was extracted from the paraffin blocks of these lesions and exons 5 - 8 of the p53 gene were analyzed by PCR and direct sequencing. In addition, mutations in K-ras codon 12 were analyzed by PCR-RFLP methods. MNNM-p53OE was located surrounding and adjoining a coexisting carcinoma and / or dysplasia. A p53 mutation was detected in 12 / 22 (54.5%) MNNM-p53OE samples, 4 / 8 (50%) dysplasia samples and 8 / 8 (100%) carcinoma samples. The p53 mutations detected in MNNM-p53OE were identical to those demonstrated in the adjoining carcinoma and / or dysplasia. No K-ras codon 12 mutation was detected in any of the samples. These results indicate that MNNM-p53OE may share an identical clonal linkage with a coexisting carcinoma and / or dysplasia, and may be an initial and submorphological form of UC-associated neoplasia. Recognition of MNNM-p53OE in biopsy specimens may help to identify patients with UC at risk of developing colorectal carcinoma.     

Mutations of p53 in Morphologically Non-neoplastic Mucosa of Long-standing Ulcerative Colitis

Two cases of ulcerative colitis (UC)-associated carcinoma or dysplasia and morphologically non-neoplastic mucosa with p53 protein overexpression (MNNM-p53OE) were selected. DNA was extracted from the paraffin blocks of these lesions and exons 5-8 of the p53 gene were analyzed by PCR and direct sequencing. In addition, mutations in K-ras codon 12 were analyzed by PCR-RFLP methods. MNNM-p53OE was located surrounding and adjoining a coexisting carcinoma and/or dysplasia. A p53 mutation was detected in 12/22 (54.5%) MNNM-p53OE samples, 4/8 (50%) dysplasia samples and 8/8 (100%) carcinoma samples. The/j53 mutations detected in MNNM-p53OE were identical to those demonstrated in the adjoining carcinoma and/or dysplasia. No K-ras codon 12 mutation was detected in any of the samples. These results indicate that MNNM-p53OE may share an identical clonal linkage with a coexisting carcinoma and/or dysplasia, and may be an initial and submorphological form of UC-associated neoplasia. Recognition of MNNM-p53OE in biopsy specimens may help to identify patients with UC at risk of developing colorectal carcinoma.     

Application of the p53 and K-ras gene mutation patterns for cytologic diagnosis of recurrent lung carcinomas

BACKGROUND: Cytologic specimens are one of the most important materials for lung carcinoma diagnosis, because they can be used in mass screening for lung carcinoma and early detection of cancer recurrence by examination of sputum and pleural fluid. METHODS: To prove the potentiality of the cytologic specimens to be subjected to molecular detection of recurrent lung carcinomas, the authors enrolled 16 patients who had undergone surgical treatment for lung carcinoma with recurrence detected by malignant pleural fluid. First, they examined K-ras gene and p53 tumor suppressor gene abnormalities in resected tumors by polymerase chain reaction-based single-strand conformation polymorphism (PCR-SSCP) analysis. Next, using a microdissection method, they investigated the use of cytologic specimens such as pleural fluid for the detection of recurrence by finding the same mutations observed in the initially resected tumor. RESULTS: Seven abnormally shifted bands were detected among six patients by PCR-SSCP analysis of surgical materials. Five of 7 abnormally shifted bands (71.4%) also were detected from microdissected malignant cells in cytologic smears. In two cases, they detected mutations by using single malignant cells in pleural fluid. CONCLUSIONS: The authors successfully detected the same mutations in recurrent cytologic specimens as those in the initially resected tumors by PCR-SSCP analysis. These findings suggest that the p53 and K-ras gene mutation patterns are effective markers for the detection of recurrent lung carcinoma in cytologic specimens. Cancer (Cancer Cytopathol) Copyright 2000 American Cancer Society.     

胆囊腺瘤-腺癌中的DNA含量和基因表达

目的 研究胆囊腺瘤从增殖到恶变中腺上皮细胞的增殖变化和基因表达。方法PCR-RFLP法测定APC、ras基因突变,ABC免疫化学组织染色法测定p53蛋白表达。用TJTY-300全自动图像分析仪测定胆囊上皮细胞核异型性和DNA含量。结果 上皮细胞核异型性和DNA含量在胆囊腺瘤-腺癌过程中逐渐增加。胆囊腺瘤中异倍体比例与腺瘤的大小有明显的关系,直径≥1cm异倍体显著增加(P<0.05)。在胆囊腺瘤-腺癌过程中可检测到APC基因和RAS基因突变。P53蛋白在这一过程中不表达。结论 胆囊腺瘤-腺癌的过程是胆囊癌发生中一条重要的途径。当胆囊腺瘤直径≥1cm时具有明显的癌变潜能。其分子改变机制与胆囊上皮不典型增生-原位癌途径不同。     

Prognostic significance of K-ras,p53, bcl-2, PCNA,CD34 in radically resected non-small cell lung cancers

The aim of this study was to investigate the prognostic significance of a panel of biological parameters in patients with radically resected non-small cell lung cancers (NSCLC). 269 cases with pathological stage I-IIIA NSCLC were retrospectively analysed. Immunohistochemistry was performed to detect protein expression of p53, bcl-2, proliferating cell nuclear antigen (PCNA) and CD34. Polymerase chain reaction (PCR)/direct nucleotide sequencing method was used to detect mutations in K-ras (codons 12, 13, 61, exons 1-2). The Kaplan-Meier estimates of survival were calculated for clinical and biological variables using the Cox model for multivariate analysis. Histological subtype and the pathologic tumour extension (pT) were the most powerful clinical-pathological prognostic factors for survival (P=0.030 and P=0.031, respectively), whereas among the biological parameters, p53 overexpression (P=0.032) and K-ras mutation (P=0.078) had a negative prognostic role, as demonstrated by multivariate analysis. Conversely, bcl-2, PCNA and CD34 expression were not correlated with survival. Statistically significant associations between p53 expression and the squamous cell carcinoma (SCC) subtype, bcl-2 expression and SCC subtype, K-ras mutation and p53 negative expression, p53 and bcl-2, bcl-2 and PCNA overexpression were observed. In conclusion, some biological characteristics such as the K-ras and p53 status may provide useful prognostic information in resected NSCLC patients, in addition to the classical clinico-pathological parameters. However, further studies are needed to clarify the value of adopting biological prognostic factor into clinical practice.     

Prevalence of p53 overexpression or mutations, but not k-ras mutations, in recurrent patients affected by colorectal-carcinoma

In order to establish prognostic indicators of poor clinical evolution in colorectal cancer, we have studied p53 abnormalities and K-ras mutations in 65 patients affected by colorectal carcinoma who had undergone radical surgery. A single event of p53 protein overexpression or p53 mutation, but not K-ras mutation, was significantly prevalent in recurrent tumors. A double event of K-ras mutation and p53 protein overexpression was prevalent in patients showing Dukes' stage C, but showed a lack of prevalence in patients who recurred. The presence of p53 protein overexpression does not assure an underlying mutation in colorectal carcinoma.     

Lack of prognostic significance of p53 and K-ras mutations in primary resected non-small-cell lung cancer on E4592: a Laboratory Ancillary Study on an Eastern Cooperative Oncology Group Prospective Randomized Trial of Postoperative Adjuvant Therapy.

PURPOSE: To determine the prognostic and predictive significance of p53 and K-ras mutations in patients with completely resected non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients were randomized preoperatively to receive adjuvant postoperative radiotherapy (Arm A) or radiotherapy plus concurrent chemotherapy (Arm B). p53 protein expression was studied by immunohistochemistry (IHC) and p53 mutations in exons 5 to 8 were evaluated by single-strand conformational analysis. K-ras mutations in codons 12, 13, and 61 were determined using engineered restriction fragment length polymorphisms. RESULTS: Four hundred eighty-eight patients were entered onto E3590; 197 tumors were assessable for analysis. Neither presence nor absence of p53 mutations, p53 protein expression, or K-ras mutations correlated with survival or progression-free survival. There was a trend toward improved survival for patients with wildtype K-ras (median, 42 months) compared with survival of patients with mutant K-ras who were randomized to chemotherapy plus radiotherapy (median, 25 months; P = .09). Multivariate analysis revealed only age and tumor stage to be significant prognostic factors, although there was a trend bordering on statistical significance for K-ras (P = .066). Analysis of survival difference by p53 by single-stranded conformational polymorphism and IHC, interaction of p53 and K-ras, interaction of p53 and treatment arm, nodal station, extent of surgery, weight loss, and histology did not reach statistical significance. CONCLUSION: p53 mutations and protein overexpression are not significant prognostic or predictive factors in resected stage II or IIIA NSCLC. K-ras mutations may be a weak prognostic marker. p53 or K-ras should not be routinely used in the clinical management of these patients.     

肺癌患者组织和痰液中p53基因、K-ras基因突变

 目的　探讨p53、K-ras基因在肺癌患者癌组织及相应痰液中改变情况及其联合检测在肺癌早期诊断中的价值。方法　对59例肺癌组织和14例肺部良性组织及相应痰液,应用PCR-SSCP-银染法检测了p53基因第5～8外显子突变情况;应用PCR-RFLP法对K-ras基因突变进行了检测。结果　p53基因在肺癌组织中突变率为37.3%,K-ras基因在肺腺癌突变率为48.0%,其它类型肺癌突变率仅为8.8%。相应痰液中两基因突变率分别为33.8%和44.0%,与组织中的突变率无明显差异,P<0.01。良性组织及相应痰液中两基因均无突变。吸烟患者的突变率(48.7%,68.5%)明显高于非吸烟患者的突变率(15.0%,11.1%),P<0.01;两基因的联合检测在肺癌的早期诊断中的价值(54.2%)明显优于单基因的检测,P<0.05。结论　痰液和组织中的基因突变率基本相似,即痰液中脱落细胞的分子遗传学改变能反映肺组织情况。因此以痰液为目标多基因的联合检测可能有助于肺癌的诊断。     

K-ras and p53 mutations in the pathogenesis of classical and goblet cell carcinoids of the appendix.

BACKGROUND: Mutations in the K-ras oncogene and the p53 tumor suppressor gene are present in approximately 50% of colonic adenocarcinomas. Goblet cell carcinoids (GCCs) are uncommon neoplasms of the appendix that appear to be intermediate between carcinoid tumors and adenocarcinomas, both histologically and biologically. The current study was undertaken to examine the role of p53 and K-ras mutations in the pathogenesis of GCCs and typical carcinoids (TCs) of the appendix. METHODS: Archival materials from 22 GCCs and 18 TCs were analyzed. K-ras mutations in codons 12, 13, and 61 were studied by a polymerase chain reaction (PCR) based designed restriction fragment length polymorphism method using mismatched nested primers. Mutations in exons 5-8 of the p53 tumor suppressor gene were analyzed in 16 GCCs and 18 TCs by PCR and single-strand conformational polymorphism followed by direct sequencing. Immunostains for p53 and chromogranin were performed in all cases. RESULTS: K-ras mutations and nuclear accumulation of p53 by immunohistochemistry were not detected in any of the GCCs or TCs. p53 mutations were found in 4 of 16 GCCs (25%) and 8 of 18 TCs (44%). Immunoreactivity for chromogranin was seen in the vast majority of GCCs and TCs. CONCLUSIONS: p53 mutations appear to play a role in the pathogenesis of some GCCs and in approximately 50% of TCs of the appendix, whereas mutations in the K-ras oncogene do not appear to be important in the development of these tumors. The minimal cytologic atypia, low incidence of metastases, and lack of K-ras mutations in goblet cell appendiceal neoplasms suggest that they are variants of carcinoid tumors. Our findings lend support to the recommendation that the therapeutic guidelines applied to TCs of the appendix should be the same for GCCs.     

Tobacco smoke-induced lung tumorigenesis in mutant A/J mice with alterations in K-ras, p53, or Ink4a/Arf

A/J mice with genetic alterations in K-ras, p53, or Ink4a/Arf were employed to investigate whether mice carrying these germline mutations would be susceptible to tobacco smoke-induced lung tumorigenesis. Transgenic mice of both genders and their wild-type littermates were exposed to environmental cigarette smoke for 6 months, followed by recovery in air for 5 months. A significant increase of lung tumor multiplicity was observed in K-ras, p53, or Ink4a/Arf mutant mice when compared with wild-type mice. Furthermore, an additive effect was observed between the mice with a mutant p53 transgene and an Ink4A/Arf deletion during tobacco smoke-induced lung tumorigenesis. Sequence analysis of the K-ras gene indicated that the mutations had occurred at either codon 12/13 or 61 in both spontaneously occurring (air control) and tobacco smoke-induced lung tumors. K-ras mutations were found in 62% of the tumors from air-control animals and 83% in those exposed to tobacco smoke. The mutation spectrum found in tumors from mice exposed to tobacco smoke is somewhat similar to that in tumors from air-control mice. In addition, we identified three novel mutations at codon 12: GGT (Gly) --> TTT (Phe), ATT (Ile), and CTT (Leu). These findings provide evidence that K-ras, p53, and Ink4a/Arf mutations play a role in tobacco smoke-related lung carcinogenesis. The similarity of the mutation spectra in the K-ras oncogene observed in tobacco smoke-induced tumors, as compared to spontaneous tumors, suggests that tobacco smoke enhances lung tumorigenesis primarily through promoting spontaneously occurring K-ras mutations.     

直肠癌p53、K-ras基因突变与临床病理的相关性研究

目的　探索p5 3、k ras基因同时突变对直肠癌的恶性行为升级的作用及其临床意义。方法　用PCR SSCP方法检测直肠癌细胞p5 3、K ras基因突变 ,分析该基因突变与临床病理因素及预后的关系。结果　直肠癌细胞p5 3、K ras基因突变与临床病理因素无关 ,生存率也无统计学差异。结论　直肠癌细胞p5 3、K ras基因突变对癌细胞恶性生物学行为升级无明显的促进作用 ,p5 3、K ras基因同时突变也无协同促癌作用 ,也不影响病人的预后。     

Detection of p53 and K-ras mutations in sputum of individuals exposed to smoky coal emissions in Xuan Wei County, China

Lung cancer mortality rates in the Xuan Wei County population are among the highest in China and are associated with exposure to indoor emissions from the burning of smoky coal. Previous studies of lung tumors from both non-smoking women and smoking men in this region showed high frequencies of mutations, consisting mostly of G-->T transversions in the p53 tumor suppressor gene and K-ras oncogene, suggesting that these mutations were caused primarily by polycyclic aromatic hydrocarbons. In this study sputum samples from 92 individuals with no evidence of lung cancer from Xuan Wei County were screened for p53 and K-ras mutations. Sputum cells were collected on glass slides by sputum cytocentrifugation, stained and cytopathologically analyzed. Cytologically non-malignant epithelial cells were taken from each sputum sample using a laser capture microdissection microscope and molecularly analyzed. Cells taken from the sputum of 15 (16.3%) individuals were mutation positive, including 13 (14.1%) individuals each with a p53 mutation, 1 (1.1%) individual with a K-ras mutation and 1 (1.1%) individual with a p53 and a K-ras mutation. p53 mutations were found in both the sputum of individuals with evidence of chronic bronchitis (3 of 46 or 6.5%) and those without evidence of this disease (11 of 46 or 23.9%). Therefore, mutations in the p53 gene and, to a lesser extent, the K-ras gene were frequent in non-malignant epithelial cells taken from the sputum of individuals without evidence of lung cancer who were exposed to smoky coal emissions in Xuan Wei County and were at a high risk for developing the disease.     

K-ras activation in non-small cell lung cancer in the dog.

To investigate the role of K-ras mutations in canine non-small cell lung cancer, we first determined the nucleotide sequence of the normal canine K-ras gene and then examined 21 canine lung tumors for activating K-ras mutations. Canine K-ras was analyzed by direct sequencing of polymerase chain reaction products generated with oligonucleotide primers derived from the human K-ras sequence. Four nucleotide differences were found between the canine and human K-ras sequence from position 5 to 211. The deduced amino acid sequence of the canine gene was identical to that of the human. Activated K-ras alleles were detected in 5 of the 21 canine lung tumors examined. The activating lesions were point mutations, predominantly in codon 12. Of the 14 adenocarcinomas examined, 2 (14%) had K-ras mutations. Two of 5 (40%) adenosquamous carcinomas and the only large cell carcinoma also contained activated alleles. The overall frequency of K-ras point mutation in non-small cell lung cancer (25%) is similar to that reported in human non-small cell lung cancer. We conclude that K-ras activation by point mutation is associated with, but not necessary for, non-small cell lung cancer development in the dog.     

Effect of 9-cis-retinoic acid on oral squamous cell carcinoma cell lines

Epstein–Barr virus (EBV) has been well documented in the aetiology of nasopharyngeal carcinoma (NPC), although its role as well as the genetic basis in the genesis of NPC have not been elucidated. The p53 gene mutations are infrequently found in NPC, but the expression of p53 protein, as well as bcl-2 oncoprotein, has been reported in a high percentage of cases, and also in association with EBV. Proliferating cell nuclear antigen (PCNA) has also been shown to be increased in NPC, suggesting its association among the overexpression of p53 and bcl-2 oncoprotein. We undertook this study to evaluate the correlation among these abnormalities in the development of NPC. The expression of p53 protein, bcl-2 oncoprotein, and the level of PCNA were investigated by immunohistochemistry in 53 patients with NPC. Twenty tissue samples from these patients were studied for p53 gene mutations by single strand conformation polymorphism (SSCP) and DNA sequencing as well as EBV genomes by polymerase chain reaction. Among the 53 specimens, 42 (79%) showed expression of p53 protein and 40 (75%) gave positive result for bcl-2 oncoprotein. A significant association was found between p53 expression and bcl-2 oncoprotein (P=0.002; Fisher's exact test) with 68% of the patients showing coexpression of both markers. The PCNA labelling index in the 53 patients varied from 5% to 80%. High PCNA labelling index was frequently found in the patients with overexpression of p53 protein and bcl-2 oncoprotein. The PCNA index in patients with p53 expression was significant higher than in those without p53 expression (P=0.002). Of the 20 patients, p53 mutations were found in four cases. EBV genomes were detected in 14 cases of which 12 cases showed overexpression of both p53 and bcl-2 and one case with only p53 expression and one case with bcl-2 expression. EBV genomes were detected in two cases with p53 mutations. We conclude that EBV is the important etiologic factor in NPC which may be involved in p53 and bcl-2 overexpression. The mutant p53 protein is correlated to deregulation of PCNA. p53 mutations participate in a small proportion of the tumorigenesis.     

Comparative analysis of K-ras point mutation,telomerase activity,and p53 overexpression in pancreatic tumours

K-ras point mutation, p53 over-expression, and telomerase activity have been proposed as molecular markers for clinical diagnosis of pancreatic carcinoma. To evaluate the clinical usefulness of these markers, we performed comparative analysis in 61 resected pancreatic samples including 15 intraductal papillary-mucinous tumours (IPMTs), 4 mucinous cystic tumours, 37 ductal adenocarcinomas, and five chronic pancreatitis samples. K-ras point mutation, telomerase activity, and p53 overexpression were analyzed using mutant allele specific amplification, the telomeric repeat amplification protocol, and immunohistochemical staining, respectively. In malignant tumours, K-ras mutation, telomerase activity, and p53 overexpression were detectable in 76, 91, and 46%, respectively, while in benign tumours, these alterations were detectable in 38, 0, and 0%, respectively. Among 15 IPMTs, K-ras mutation was detectable in 4 (80%) of 5 IPMT-adenomas, 4 (80%) of 5 IPMT-carcinomas and 2 (66%) of 3 papillary-mucinous carcinomas, which are invasive carcinomas derived from IPMTs. Telomerase activity was not detectable in IPMT-adenomas, but was detected in all 5 IPMT-carcinomas and 3 papillary-mucinous carcinomas. p53 overexpression was not detected in IPMTs, but was detected in 2 (66%) of 3 papillary-mucinous carcinomas, indicating that telomerase is likely to be activated concomitant with carcinogenesis. These results suggest that telomerase activity is the most useful as a differential diagnostic marker between malignant and benign pancreatic tumours.     

p53 and K-ras mutations in lung cancers from former and never-smoking women

Somatic p53 mutations are common in lung cancer. Active cigarette smoking is positively correlated with the total frequency of p53 mutations and G:C to T:A transversions on the nontranscribed (DNA coding) strand. Mutational hotspots within the p53 gene, e.g., codon 157, have been identified for tobacco-related lung cancer, whereas these same mutations are found rarely in other cancers. Such data implicate specific p53 mutations as molecular markers of smoking. Because limited data exist concerning the p53 mutation frequency and spectra in ex-smokers and nonsmokers, we have analyzed p53 and K-ras mutations in 126 lung cancers from a population-based case-control study of nonsmoking (n = 117) or ex-smoking (n = 9) women from Missouri with quantitative assessments of exposure to environmental tobacco smoke. Mutations in the p53 gene were found in lung cancers from lifetime nonsmokers (19%) and ex-smokers (67%; odds ratio, 9.08; 95% confidence interval, 2.06-39.98). All deletions were found in tumors from patients who were either ex-smokers or nonsmokers exposed to passive smoking. The G:C to A:T transitions (11 of 28; 39%) were the most frequent p53 mutations found and clustered in tumors from lifetime nonsmokers without passive smoke exposure. The incidence of K-ras codon 12 or 13 mutations was 11% (14 of 115 analyzed) with no difference between long-term ex-smokers and nonsmokers. These and other results indicate that p53 mutations occur more commonly in smokers and ex-smokers than in never-smokers. Such comparisons provide additional evidence of genetic damage caused by tobacco smoke during lung carcinogenesis.     

卵巢上皮性囊腺性肿瘤组织中C-erbB-2、PCNA和p53蛋白的表达及临床病理学意义

目的 :探讨原癌基因C erbB 2、增殖细胞核抗原 (proliferatingcellnuclearantigen ,PCNA)、抑癌基因p5 3在卵巢上皮性囊腺性肿瘤组织中的表达及其临床病理学意义。方法 :应用抗生蛋白链菌素标记法 (LSAB)和图象分析系统方法检测卵巢上皮性囊腺性肿瘤组织中 (其中 61例良性肿瘤、19例交界性肿瘤、4 4例恶性肿瘤 )C erbB 2、PCNA及p5 3蛋白的表达。结果 :1)C erbB 2、PCNA、p5 3三指标在囊腺瘤、交界性囊腺瘤、囊腺癌中阳性表达率均呈梯度升高 ,差异有极显著性 (P <0 0 0 1)。其中PCNA与p5 3在浆液性囊腺癌组织中的表达显著高于交界性肿瘤及黏液囊腺癌组织 (P <0 0 5 )。 2 )C erbB 2、PCNA和p5 3在囊腺瘤组织中的阳性细胞平均积分光密度值 (染色强度 )均显著低于交界性瘤和恶性肿瘤 ,且差异有极显著性 (P <0 0 0 1)。 3)p5 3蛋白表达与囊腺癌临床分期、组织学分级有相关性 (P <0 0 5 )。 4 )p5 3+PNCA和C erbB 2 +PCNA +p5 3联合表达率在交界性囊腺瘤与囊腺癌之间差异有显著性 (P <0 0 1)。结论 :C erbB 2、PCNA和p5 3蛋白的高表达与囊腺癌的发生有密切关系 ,可作为卵巢上皮性囊腺性肿瘤恶性化的分子标志。PCNA和p5 3蛋白的免疫组化检测可成为卵巢上皮性囊腺性肿瘤鉴别诊断的客观辅助指标 ,并为其诊     

Frequent p53 mutation in brain (fetal)-type glycogen phosphorylase positive foci adjacent to human 'de novo' colorectal carcinomas

'de novo' carcinogenesis has been advocated besides 'adenoma carcinoma sequence' as another dominant pathway leading to colorectal carcinoma. Our recent study has demonstrated that the distribution of brain (fetal)-type glycogen phosphorylase (BGP) positive foci (BGP foci) has a close relationship with the location of 'de novo' carcinoma. The aims of the present study are to investigate genetic alteration in the BGP foci and to characterize them in the 'de novo' carcinogenesis. 17 colorectal carcinomas without any adenoma component expressing both immunoreactive p53 and BGP protein were selected from 96 resected specimens from our previous study. Further investigations to examine the proliferating cell nuclear antigen (PCNA)-labelling index, and the p53 and the codon 12 of K-ras mutation using the polymerase chain reaction-single strand conformation polymorphism were performed in the BGP foci, BGP negative mucosa and carcinoma. The BGP foci were observed sporadically in the transitional mucosa adjacent to the carcinoma in all cases. The PCNA labelling index in the BGP foci was significantly higher than that in the BGP negative mucosa (P< 0.001). p53 mutations were observed in 8 carcinomas, but no K-ras mutation was detected. Interestingly, although none of the overexpressions of p53 protein was detected immunohistochemically in the BGP positive foci, the p53 gene frequently (41.2% of the BGP foci tested) mutated in spite of no K-ras mutation. The present study demonstrates potentially premalignant foci in the colorectal transitional mucosa with frequent p53 gene mutation. It is suggested that BGP foci are promising candidates for the further investigation of 'de novo' colorectal carcinogenesis.     

Alterations of the p53 gene are common and critical events for the maintenance of malignant phenotypes in small-cell lung carcinoma.

To clarify the incidence, timing and pathogenetic significance of p53 gene alterations in the progression of small-cell lung carcinoma (SCLC), 17 primary tumors, 13 metastases and nine cell lines from 27 patients were analysed by a polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. Allelic losses and mutations of the p53 gene were detected in 24 out of 25 informative cases (96%) and 23 out of 27 cases (85%) respectively. Simultaneous losses and mutations were detected in all 16 stage III-IV tumors, while these alterations were detected only in 3 of 6 stage I-II tumors. When allelic losses and/or mutations were detected in the primary tumors, the same alterations were always maintained in the process of metastasis. In three cases, identical p53 alterations were detected among different organ metastases. The mutations detected in five cell lines were also detected in the corresponding original tumors. These results suggest that the alterations of the p53 gene are common and early events, but probably not the first events, in the development of SCLC, and that these alterations are essential for the maintenance of malignant phenotypes in the progression of SCLC.