High frequency of K-ras mutations in normal appearing lung tissues and sputum of patients with lung cancer.

To evaluate the possible use of mutant ras as a biomarker for lung cancer, we have analyzed "normal appearing" lung tissue, lung tumor, lung metastases and sputum samples from patients with non-small cell lung cancer (NSCLC). As a control, we used lung tissue and sputum samples from patients without oncological diseases or lung disorders. Our analyses were performed with the aid of enriched PCR (EPCR), a method which enables detection of ras mutation even if present at low incidence. EPCR identified K-ras codon 12 mutations in 10% of lung tissues obtained from patients with no lung diseases, whereas the same mutation was detected in 60% of samples of normal appearing lung tissues obtained from patients with NSCLC, 62% of NSCLC tumors and 80% of metastases. Analysis of sputum samples of patients with NSCLC identified 47% to harbor mutant ras allele, whereas 12.5% of controls diagnosed with non-oncological lung diseases carried this mutation. Most of these mutations were detected with the aid of EPCR only, indicating that a minority of cells in a given sample harbor this mutation. The ability to detect K-ras codon 12 mutation in 60% of lung tissue samples and in 47% of sputum samples taken from patients with lung cancer (as compared with 10% and 12.5% of respective controls) points to the potential use of ras mutation as a biomarker for exposure and possible identification of patients who may be at higher risk of developing lung cancer.

Detection of K-ras mutation in colonic effluent samples from patients without evidence of colorectal carcinoma.

BACKGROUND: K-ras gene mutation appears in more than 50% of patients with colon tumors. Both its frequency and early appearance may qualify this mutation as a potential biomarker. To enable early detection of mutant K-ras alleles, we had previously developed a sensitive polymerase chain reaction (PCR)-based assay, i.e., enriched PCR, which enables detection of one mutant K-ras allele present within 10,000 normal alleles. Using the enriched PCR, we were able to detect mutant K-ras alleles in "normal-appearing" colonic mucosa in patients with colorectal cancer. PURPOSE: A study was initiated to determine whether mutant K-ras alleles could be identified in colonic effluent samples of patients who may be at risk to develop colorectal cancer. METHODS: Over 9 years, colonic effluent samples were collected prior to routine colonoscopy from 39 patients who were apparently free of colorectal cancer. These samples were collected from patients with a family history of colorectal cancer (n = 7), adenomatous polyps (n = 7), previously resected colorectal cancer (n = 5), inflammatory bowel disorders (n = 13), normal colonoscopic examination (n = 6), and familial adenomatous polyposis (n = 1). All of the samples were double coded and analyzed for K-ras gene mutation. RESULTS: Of the 39 patients, seven were found to harbor mutant K-ras codon 12 alleles. Mutations were found in patients with a family history of colorectal cancer (three of seven), adenomatous polyps (one of seven), previously resected colorectal carcinoma (two of five), and familial adenomatous polyposis (one of one). In one case, effluent was found to harbor a mutant K-ras allele 4 years before the patient was diagnosed with colorectal cancer. CONCLUSIONS: (a) Effluent samples contain enough DNA to be detected with enriched PCR. Such samples may well be representative of the entire colon in general as opposed to a localized area such as that usually analyzed during colonoscopy. (b) K-ras gene mutation can be identified in routinely obtained colonic washings of patients who are at risk of developing colorectal cancer. Such mutations were absent in patients with inflammatory bowel disorders and in those who had undergone normal colonoscopic examinations. Detection of K-ras mutation in colonic washings may assist in identifying patients who may be at high risk for developing adenocarcinoma of the colon. IMPLICATIONS: The ability to examine colonic effluents provides a powerful and convenient source of sampling and may be adapted for future large-scale screening.

A transcriptional inhibitor induced in human melanoma cells upon ultraviolet irradiation.

Nuclear proteins from human melanoma cells exhibit strong binding activity to the UV response element (TGACAACA); however, this binding is inhibited following UV-C irradiation. In contrast, the binding of nuclear proteins from rodent fibroblasts and human keratinocytes to the UV-responsive element is initially weak and increases significantly upon UV irradiation. The addition of nuclear proteins from UV-irradiated melanoma cells to those prepared from nonirradiated cells inhibited the binding to the UV-responsive element in a concentration-dependent manner. Fast protein liquid chromatographic analysis of nuclear proteins from UV-irradiated melanoma cells revealed 12 and 14 kilodalton proteins within a fraction which also contained the inhibitory activity. The inhibitor blocks the binding of proteins to three other target sequences, AP1, CREB, and PEBP2, as well as the in vitro transcription of SV40 promoter sequences. The inhibitor was also found in UV-irradiated melanocytes, suggesting that it is tissue specific. The induction of a transcriptional inhibitor in response to UV irradiation represents a regulatory event that may play an important role in the transcriptional response of both normal and malignant melanocytes to UV irradiation.

[Analysis of 117 cases of percutaneous fine-needle pneumocentesis with ultrasonic guiding].

In this paper, we report 117 cases of percutaneous fine-needle pneumocentesis with ultrasonic guiding in the pulmonary mass lesions. The cytologic results revealed that the positive rate of malignant tumours was 84.7% (83/98), the suspected positive rate was 5.1% (5/98), the sensitivity was 89.8%. The false negative rate was 9.2% (9/98). One case was false positive. The diagnostic specialty of benign tumour (19 cases) was 94.7%. The total correct diagnostic rate was 90.6%. After the pneumocentesis, the complication included 2 cases of pneumothorax. 5 cases of hemoptysis (4.3%). This paper discussed mainly the diagnostic value and the limitation of this method. We think that the pneumocentesis with ultrasonic guiding is simpler and has less complications than radiologic guiding.

Amplification of the EGF receptor and c-myc genes in human esophageal cancers.

The incidence of esophageal cancer is extremely high in Linxian County and certain other regions of the People's Republic of China. Epidemiologic and laboratory studies suggest that N-nitroso carcinogens and other environmental factors play a causative role. In the present study, employing over 100 DNA samples obtained from Lin-xian patients who underwent surgery for esophageal cancer, we have found a significant frequency of amplification of either the human epidermal growth factor receptor (HER-I) gene or the c-myc oncogene. These changes were found not only in tumor specimens, but also in adjacent non-tumor (grossly normal) tissue specimens obtained from patients with esophageal cancer. RNA samples were also obtained from over 30 tissue samples. These revealed considerable variation in the abundance of HER-I and c-myc transcripts in both the tumor and adjacent non-tumor specimens. A few samples revealed extremely high levels of these transcripts. Thus, changes in gene copy number or level of expression of HER-I or c-myc DNA sequences may play an important role in the pathogenesis of esophageal cancer in this high-risk region.