痰液K-ras p53检测辅助诊断肺癌

（目的〕了解分子生物学检测方法是否对肺癌的诊断具有辅助价值。（方法）痰液处理方法为痰液0．5毫升加入痰处理液制备细胞沉淀液，酚氯仿提取DNA；SSCP－PCR银染和RFLP－PCR方法对痰液中P53、K－ras突变情况进行检测。（结果）在确诊的76例肺癌病人中，p53突变率为40．8％，K－ras突变率为25．0％，突变与肺癌类型、分期未见明显相关，其中有29例病人痰液普通脱落细胞学检测明性．痰液p53或K－ras突变阳性，最后经纤支镜刷检，活检部分经过手术征实为肺癌，有12例经手术证实为Ⅰ～Ⅱ期的相对早期的肺癌。(结论)痰液SSCP－PCR、RELP-PCR方法检测癌基因突变具有简便、实用、准确、可行的特点。对部分疑为肺癌而痰液脱落细胞学检测阴性的病人具有一定的辅助诊断价值。     

肺癌组织中p53、K-ras、p15、p16基因的改变

目的　探讨p5 3、K ras、p15、p16基因在肺癌组织中改变情况及多基因联合检测在肺癌诊断中的价值。 方法　对 5 9例肺癌组织和 14例肺部良性组织 ,应用PCR SSCP 银染法检测 p5 3基因第 5～ 8外显子突变情况 ;应用PCR RFLP法对K ras基因突变进行检测 ;并应用PCR法检测 p15、p16基因纯合缺失情况。 结果　肺癌组织中 p5 3、p15、p16基因改变频率分别为 3 7.3 %、11.9%、2 3 .8% ,而在肺部良性组织中只有 1例 p16基因阳性。在 2 5例肺腺癌中 ,K ras基因突变率为 48.0 % ,其它类型肺癌中突变率仅为 8.8% ,而 14例良性组织中未检测出K ras基因突变。另外 ,p5 3基因和K ras基因突变与吸烟存在着密切关系 ,即吸烟者出现突变的频率 ( 4 8.7% ,68.5 % )明显高于非吸烟者 ( 15 .0 % ,11.1% ) ,P <0 .0 1。 4种基因联合检测敏感度为 78.0 % ,明显高于单一基因 (以阳性率最高的 p5 3为例 )的敏感度 3 7.3 %。 结论　p5 3基因、K ras基因和 p16基因在肺癌组织中改变率相对较高 ;多基因的联合检测有助于肺癌的早期诊断和筛查。     

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。     

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。     

肺癌病人痰液标本p53基因突变临床流行病学分析

[目的]探讨痰液标本p53基因突变检测用于肺癌高危人群筛查和肺癌早期诊断方面的意义。[方法]应用PCR鄄SSCP对63例肺癌患者和30例肺良性疾病的肺组织和痰液细胞中p53基因5～8外显子的突变进行了检测,并采用临床流行病学的方法进行分析。[结果]肺癌病人组肺癌组织中p53基因突变率为49.2%(31/63),对照组组织中突变率为3.3%(1/30),两组差别有统计学意义(P<0.001)。肺癌组痰液标本中p53突变率为23.8%(15/63);肺良性疾病患者痰液中未发现p53基因突变。以痰液标本p53基因突变为诊断指标,诊断的敏感度为45.2%,特异度为96.8%,标化阳性预告值为93.5%,标化阴性预告值为63.9%,标化一致性为71.0%。[结论]检测痰液中p53基因突变能间接反映其在肺组织中的改变,该方法可作为肺癌高危人群筛查以及肺癌诊断的无创性手段之一。     

肺癌发病机理的遗传学及分子学现象观察

对主要癌基因和肿瘤抑制基因的研究表明NSCLC与SCLC在遗传损伤方面有特征性区别,并可以此结合临床加以鉴别。所有肺癌中半数以上具有p53肿瘤抑制基因突变,但并不表明突变与存活之间有关联。约20％NSCLC病人的肿瘤及肿瘤细胞系中发生ras家族癌基因的突变,相反45例SCLC病人的肿瘤及肿瘤细胞系ras基因无一例突变。回顾调查存活的NSCLC病人,发现K-ras基因突变是决定患者预后的一个不利因素。吸烟肿瘤病人K-ras基因突变比非吸烟者更常见,而对接触放射性元素镭的职业性肺癌并未检测出K-ras突变。肺癌的p53和K-ras基因突变几乎都是G→T颠换,而其他癌症则是G→A颠换。从密切随访     

原发性非小细胞肺癌中K－ras基因突变的研究

目的探讨非小细胞肺癌（Non－smallcelllungcancer,NSCLC）组织中K－ras第12密码子点突变与NSCLC发生和发展的相关性。方法采用针对K－ras基因第12密码子特异点突变方式的引物进行PCR及银染法,分析175例新鲜NSCLC手术切除标本、43例癌旁组织及5例良性肺部疾患组织中K－ras基因第12密码子中CGT、GTT和GAT三种不同点突变方式。结果175例NSCLC组织中出现K－ras12密码子GGT→CGT突变率为34．86％（61／175）,GGT→GTT突变率40．57％（71／175）及GGT→GAT突变率37．71％（66／175）,总突变率为62．3％（109／175）。其中,同时出现CGT／GTT二个点突变为10．1％(11／109),CGT／GAT9．2％(10／109),GTT／GAT12．8％(14／109),而CGT／GTT／GAT均出现突变占23．9％(26／109)。其中Ⅰ期、Ⅱ期、Ⅲ期突变率分别为64．3％、56．8％及64．0％,另外腺癌突变率为63．8％、鳞癌为60．5％及腺鳞癌为64．5％,因此K－ras点突变与肺癌的分期及病理类型均无相关性（P＞0．05）。然而,37例腺癌突变组中出现GTT／GAT突变率为17．2％(10／58)明显高于鳞癌的3．5％(3／86),二者具有明显差异（P＜0．01）。43例癌旁组织与5例良性肺部疾患组织均未发现K－ras点突变。结论K－ras12密码子点突变及多点突变普遍存在于NSCLC中,其中肺腺癌出现GTT／GAT二个点突变明显高于鳞癌,结果提示K－ras基因点突变是肺癌发生和发展的一个重要因素。     

原发性非小细胞肺癌中K-ras基因突变的研究

目的：探讨非小细胞肺癌（Non－small cell lung cancer NSCLC）组织中K－ras第12密码子点突变与NSCLC发生和发展的相关性。方法：采用针对K－ras基因第12密码子特异点突变方式的引物进行PCR及银染法,分析175例新鲜NSCLC手术切除标本、43例癌旁组织及5例良性肺部疾患组织中K－ras基因第12密码子中CGT、GTT和GAT三种不同点突变方式。结果：175例NSCLC组织中出现K－ras 12密码子GGT→CGT突变率为34．86％（61／175）,GGT→GTT突变率40．57％（71／175）及GGT→GAT突变率37．71％（66／175）,总突变率为62．3％（109／175）。其中,同时出现CGT／GTT二个点突变为10．1％ 11／109CGT／GAT 9．2％10／109 GTT／GAT 12．8％ 14／109,而 CGT／GTT／GAT均出现突变占23．9％26／109。其中Ⅰ期、 Ⅱ期、Ⅲ期突变率分别为64．3％、56．8％及64．0％,另外腺癌突变率为63．8％、鳞癌为60．5％及腺鳞癌为64．5％因此K－ras点突变与肺癌的分期及病理类型均无相关性（P＞0．05）。然而,37例腺癌突变组中出现GTT／GAT突变率为17．2％ 10／58明显高于鳞癌的3．5％3／86二者具有明显差异（P＜0．01）。43例癌旁组织与5例良性肺部疾患组织均未发现K－ras点突变。结论：K－ras12密码     

非小细胞肺癌患者RAS基因突变临床特征和预后分析

摘 要：［目的］ 探讨非小细胞肺癌RAS基因突变的临床特征和预后。［方法］ 对475例非小细胞肺癌患者进行RAS基因检测和随访。Kaplan-Meier法计算生存率,Log-rank法进行生存率检验。［结果］ 475例非小细胞肺癌中,KRAS基因突变的突变率为8.00% (38/475),其中吸烟患者的KRAS突变频率远高于非吸烟患者(15.76% vs 4.41%,P<0.01)。 346例非小细胞肺癌中NRAS基因突变的突变率为0.29% (1/346);315例非小细胞肺癌中HRAS基因突变的突变率为0.63% (2/315)。RAS基因复合其他基因突变15例,中位生存时间29.8个月;而单纯RAS突变26例中位生存时间16.3个月(P=0.15)。［结论］ 在NSCLC患者中,吸烟患者的KRAS基因突变频率高于非吸烟患者。RAS基因突变的非小细胞肺癌临床特征上无统计学差异;复合突变比单纯突变临床获益更多。     

痰液K-ras P53基因检测对肺癌的辅助诊断价值

目的；76例疑为肺癌病人痰液中P53和K-ras最常见突变位点进行了检测，以了解分子生物学检测方法是否对肺癌的诊断具有辅助诊断价值。方法；痰液处理方法：痰液0．5毫升加入痰处理液制备细胞沉淀液，酚氯仿提取DNA；SSCP-PCR银染和RFLP-PCR方法对痰液中P53、K-ras突变情况进行检测。结果：在确诊的76例肺癌病人中，P53突变率为40．8％，K-ras突变率为25%，突变与肺癌类型，疾病分期未见明显相关．其中有29例病人痰液普通脱落细胞学检测阴性，痰液P53或K-ras突变阳性，最后经，奸支镜刷检、活检部分经过手术证实为肺癌，有12例经手术证实为1-1期的相对早期的肺癌。结论；痰液SSCP-PCR、RELP-PCR方法检测癌基因突变具有简便、实用、准确、可行的特点。对部分疑为肺癌而痰液脱落细胞学检测阴性的病人具有一定的辅助诊断价值。值得临床进一步开展深入的研究。     

Differential frequencies of p16(INK4a) promoter hypermethylation, p53 mutation, and K-ras mutation in exfoliative material mark the development of lung cancer in symptomatic chronic smokers.

PURPOSE: The aim of this study was to investigate the frequency of three (epi)genetic alterations (p53 and K-ras mutations and p16(INK4a) promoter hypermethylation) in symptomatic chronic smokers compared with patients with lung cancer and to evaluate the use of exfoliative material for such analyses. PATIENTS AND METHODS: Fifty-one patients with histologically confirmed lung cancer and 25 chronic smokers (> 20 pack-years) were investigated for mutations in the K-ras (codon 12) and p53 (codons 248, 249, and 273) genes and for allelic hypermethylation of the p16(INK4a) gene. DNA was isolated from sputum and bilateral bronchial lavage, and brushings were taken at bronchoscopy. RESULTS: Forty-one genetic lesions were detected within exfoliative material from the group of 51 patients with lung cancer and 10 lesions in the chronic smoker group. K-ras mutations occurred exclusively in the lung cancer group, whereas p53 mutations and p16(INK4a) promoter hypermethylation were also found in chronic smokers. Three of eight chronic smokers who harbored an (epi)genetic alteration were subsequently diagnosed with lung cancer. Analysis of sputum yielded information equivalent to that of samples obtained during bronchoscopy. CONCLUSION: p16(INK4a) promoter hypermethylation and p53 mutations can occur in chronic smokers before any clinical evidence of neoplasia and may be indicative of an increased risk of developing lung cancer or of early disease. K-ras mutations occur exclusively in the presence of clinically detectable neoplastic transformation. Molecular analysis of sputum for such markers may provide an effective means of screening chronic smokers to enable earlier detection and therapeutic intervention of lung cancer.     

Molecular alterations in spontaneous sputum of cancer-free heavy smokers: results from a large screening program.

PURPOSE: The high mortality rate for lung cancer is likely to be reduced by the development of a panel of sensitive biological markers able to identify early-stage lung cancers or subjects at high risk. The aim of this study was to establish the frequency of K-ras and p53 mutations and p16(INK4A), RASSF1A, and NORE1A hypermethylation in sputum of a large cohort of cancer-free heavy smokers and to assess whether these markers are suitable for a routine use in the clinical practice for the early diagnosis of pulmonary cancer. EXPERIMENTAL DESIGN: Sputum samples were collected from 820 heavy smokers. Inclusion criteria consisted of radiologic and cytologic absence of pulmonary lesions, age at least 60 years, male gender, and a smoking history of at least 20 pack-years. RESULTS: The analysis identified 56 individuals (6.9%) with one molecular alteration. p53 mutation and p16(INK4A), RASSF1A, and NORE1A methylation frequencies were 1.9%, 5.1%, 0.8%, and 1.0%, respectively; no K-ras mutations were found. One patient with p53 mutations was diagnosed with an early-stage lung cancer after 3-years of follow-up. The molecular analysis of bronchoscopy samples confirmed in half of the cases alterations present in sputum without revealing additional molecular changes. CONCLUSIONS: Genetic and epigenetic abnormalities can be detected in cancer-free heavy smokers. Although the predictive value of the cancer risk is still to be established as it requires not less than 5 years of follow-up, p53 and p16(INK4A) are more promising candidates than K-ras, RASSF1A, and NORE1A for the pulmonary molecular screening of heavy smokers healthy individuals.     

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.     

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.     

Expression and alteration of ras and p53 proteins in patients with lung carcinoma accompanied by idiopathic pulmonary fibrosis

BACKGROUND: The ras oncogene and the p53 tumor suppressor gene play important roles in the carcinogenic process of lung carcinoma. The authors evaluated whether alterations of the ras and p53 proteins may contribute to the development of lung carcinoma in patients with idiopathic pulmonary fibrosis (IPF) and whether such alterations may explain the high incidence of lung carcinoma among patients with IPF. METHODS: Lung tissues were obtained from 35 patients who had IPF without complications of lung carcinoma and from 36 patients who had IPF with complications of lung carcinoma. Altered expression of ras and p53 proteins was evaluated by immunohistochemistry, and mutations of both genes were evaluated by polymerase chain reaction-single strand conformation polymorphism and sequencing analyses. RESULTS: The frequency of expression of ras protein in type II alveolar pneumocytes was significantly greater in lung tissues from patients with IPF who had lung carcinoma compared with lung tissues from patients with IPF who did not have lung carcinoma (75% vs. 40%, respectively; P < 0.01). K-ras point mutation in codon 12 (GGT to GTT transversion) was detected in lung tissue with interstitial pneumonia, in which ras protein was overexpressed in type II alveolar pneumocytes obtained from 2 of 41 patients with IPF complicated by lung carcinoma, causing amino acid substitution (Gly to Val) in both patients. A p53 mutation was detected in three of six lung tissue samples from patients who had IPF lung with positive p53 immunoreactivity, and multiple mutations were detected in two samples. CONCLUSIONS: Expression of ras protein in type II alveolar pneumocytes and mutation in the codon 12 of K-ras gene in lung tissue may contribute to the induction of lung carcinoma in patients with IPF. Furthermore, the presence of multiple mutations in the p53 gene may explain the high incidence lung carcinoma in patients with IPF.     

GSTM1, P53 and K-ras molecular detection in resectable non-small cell lung cancer by denaturing gradient gel electrophoresis-bronchoalveolar lavage fluid analysis

BACKGROUND: Understanding molecular abnormalities could potentially lead to novel investigational approaches in the molecular epidemiology of lung cancer. These might include the identification of patients at high risk for primary NSCLC and the surveillance of patients with known NSCLC who are being treated using lung-sparing surgical strategies. MATERIALS AND METHODS: The PCR-Denaturing Gradient Gel Electrophoresis (DGGE) strategy was used for primary tumors and corresponding bronchalveolare lavage (BAL) samples. RESULTS: We recruited 36 consecutive patients with NSCLC, 28 (77.7%) males and 8 females (22.3%). DGGE showed a good rate of accuracy in the genetic screening of K-ras and p53 mutations in BAL specimens. Specific mutations were more often detected in BAL fluid from patients with not peripheral tumors than parenchymal or peripheral tumors (p53: 85.7%, p=0.0004; K-ras: 75%, p=0.001). p53 mutations were more frequent in BAL fluid from squamous cell carcinomas (22%) than from adenocarcinomas (15%). A significant correlation was observed between null GST-Ml genotype and p53 overall mutations (p=0.0003), K-ras mutations (p=0.02), non peripheral tumors (p=0.04) and smoking habits (p=0.002). CONCLUSIONS: We observed that null GSTMl genotype is strongly related to p53 mutations. Individuals at high risk for primary NSCLC, such as heavy smokers or individuals exposed to occupational carcinogens, could be screened by BAL-analysis for cancer biomarkers of susceptibility like GSTM-1 in large scale molecular epidemiology studies.     

Cigarette smoking is strongly associated with mutation of the K-ras gene in patients with primary adenocarcinoma of the lung.

BACKGROUND: The majority of lung carcinoma cases occur in current or former smokers. K-ras gene mutations are common in lung adenocarcinoma and have been associated with cigarette smoking, asbestos exposure, and female gender. METHODS: In the current study, the authors examined the contribution of cigarette smoking to K-ras gene mutations in patients with primary lung adenocarcinoma. Smoking histories were obtained from 106 prospectively enrolled patients with primary adenocarcinoma of the lung. RESULTS: K-ras mutations were detected in the primary tumor using an allele-specific ligation assay. Ninety-two of the 106 patients (87%) with lung adenocarcinoma were smokers. Nonsmokers with this tumor were more likely to be women (11 of 14; 79%), whereas the majority of smokers (57%) were men. K-ras mutations were detected in 40 of 106 tumors (38%) and were significantly more common in smokers compared with nonsmokers (43% vs. 0%; P = 0.001). CONCLUSIONS: The results of the current study confirm and extend previous observations that smokers with adenocarcinoma of the lung are more likely to have K-ras mutant tumors compared with nonsmokers. The strong link between cigarette smoking and K-ras mutations in adenocarcinoma of the lung supports the role of specific tobacco carcinogens in the etiology of this malignancy.     

p53 and K-ras gene mutations correlate with tumor aggressiveness but are not of routine prognostic value in colorectal cancer.

PURPOSE: p53 gene and K-ras mutations are among the most common genetic alterations present in colorectal cancer. The prognostic utility of such mutations remains controversial. The purpose of this study was to prospectively evaluate the prognostic significance of p53 and K-ras gene mutations in colorectal cancer. PATIENTS AND METHODS: One hundred forty patients were analyzed. Tumors belonging to the microsatellite mutator phenotype were excluded (n = 8). Mutations at the K-ras and p53 genes were detected and characterized by restriction fragment length polymorphism, single-strand conformation polymorphism, and sequencing, as appropriate. RESULTS: p53 mutations were detected in 66 (50%) and K-ras mutations were detected in 54 (41%) of the 132 patients. In 26 cases (20%), ras and p53 mutations coexisted; in 38 cases (29%), neither mutation was found. Multivariate analysis of the whole population analyzed (n = 132) showed that survival was strongly correlated with the presence of p53 mutations alone or in combination with K-ras mutations (P = .002; log-rank test). When only patients undergoing a radical resection were considered (R0; n = 101), p53 mutations were no longer of prognostic significance. CONCLUSION: p53 mutations alone or in combination with K-ras mutations are correlated with a worse outcome. However, the routine use of these mutations as prognostic markers in the clinical setting is not recommended.