Analysis of DNA aneuploidy as a tumor marker

DNA aneuploidy (DA) was examined in adult leukemia using flow cytometry, and the method and the clinical implication of DA as a tumor marker were evaluated. The method was simple, rapid, objective, quantitative and further did not need any mitotic cells, so was proved to be very useful for screening of DA. While, DA was detected in 50 (27%) out of 185 adult cases with various types of leukemia. The frequencies of DA in the subtypes of leukemia were 55% in ATL, 26% in ALL, 17% in ANLL, 26% in CML-BC and 6% in CLL, respectively. When compared with other subtypes, the frequency in ATL was significantly higher (p less than 0.01), which suggested a special entity of this disease. In general, however, the frequency of DA in leukemia was rather low, which indicated the difficulty in application of DA by itself in diagnosis of leukemia. While, in cases with DA, DA was very useful as a tumor marker in monitoring the clinical course, for example, in the detection of early relapse or recruitment of leukemic cells. Furthermore, DA was found to be a good prognostic factor which indicates a poor prognosis in cases with ANLL and CML-BC.     

承前启后再创佳绩

值此《内镜》杂志更名为《中华消化内镜杂志》 10周年及2005年新年到来之际,我谨代表中华消 化内镜杂志编委会向全国消化内镜的同道们致以节 日的祝贺和问候。 过去的10年来,中华消化内镜杂志在全国广大 消化内镜工作者的大力支持下,通过编委会及编辑 部同仁们的辛勤劳动和努力,杂志的期刊特色、学术 水平、栏目种类、文章编排、印刷质量等各方面都取 得了长足的进步;在此基础上逐年获得了由中华医     

Aberrant promoter CpG methylation as a molecular marker for disease monitoring in natural killer cell lymphomas

Natural killer (NK) cell lymphomas lack suitable clonal markers for tumour cell detection, making the monitoring of minimal residual lymphoma difficult. Aberrant promoter CpG methylation occurs frequently in NK cell lymphomas. The objective of this study was to assess the potential of aberrant methylation as a surrogate tumour marker. Twenty-five primary tumours and 105 serial biopsies taken at various time points after treatment were examined using a methylation-specific polymerase chain reaction (MSP) for a panel of genes, comprising p73, p16, hMLH1, RARbeta and p15, previously shown to be methylated in NK cell lymphomas. All samples underwent independent morphological examination, supplemented by immunostaining for CD56 and in-situ hybridization for Epstein-Barr-virus-encoded RNA. Primary tumours showed the frequent methylation of the genes p73 (92%), p16 (71%), hMLH1 (61%), RARbeta (56%) and p15 (48%). MSP results in serial post-treatment biopsies were correlated with clinicopathological findings. Results were concordant in 89 follow-up samples (18 samples, histology positive/MSP positive; 71 samples, histology negative/MSP negative) and discordant in 16. Fifteen samples were histology negative/MSP positive, and tumour involvement was subsequently confirmed (positive re-biopsies or relapses at the same sites), indicating that MSP was more sensitive for minimal lymphoma detection. One sample was histology positive/MSP negative; a subsequent histological review and continuous clinical remission of the patient did not support tumour involvement. Our findings suggest that MSP for aberrantly methylated genes is a potentially valuable molecular marker for detecting either residual or relapsed disease in NK cell lymphoma patients.     

Characterization and use of a DNA probe as an epidemiological marker for Pseudomonas aeruginosa

We used DNA restriction fragments, derived from the exotoxin A gene and surrounding sequences, as an epidemiological marker for Pseudomonas aeruginosa. Using these DNA fragments as probes in Southern blot hybridizations and/or total genomic digestions, we were able to distinguish greater than 100 different strains of P. aeruginosa. The stability of the marker in vitro was established by using well-characterized strains, which were stored under different conditions and subjected to chemical mutagenesis. The stability of the marker within a given strain in vivo was established during experimental infection in the chronic rat lung model of pseudomonas pneumonia. P. aeruginosa serially cultured from individual patients with cystic fibrosis were examined by using this marker. Isolates that varied in colonial morphology, serotype, and biotype were identical when analyzed by Southern blot hybridization using the fragment as a probe. Indistinguishable isolates (by serotyping, biotyping, and antibiograms) cultured from two unrelated patients were easily distinguished by using Southern blot analysis.     

Cellular DNA content as a marker of neoplasia in man

Cellular DNA content was determined by means of flow cytometry with the use of DNA specific fluorochromes (ethidium bromide and mithramycin) in 516 human tissue samples from 440 subjects. Compared to human granulocytes as diploid reference standard, there was a 91 percent incidence of DNA content abnormality difference in DNA content of tumor G${}_{\mathrm{<mtext>1</mtext><mtext>0</mtext>}}$ cells indicating aneuploidy in 118 patients with neoplastic disease (including nine patients who lacked histopathologic evidence of malignancy at the time of study). Ninety-four percent of aneuploid tumors were hyperdiploid. Except for six solid tumors with biclonal abnormalities in DNA content, the remainder of neoplasms were characterized by uniform DNA content with little dispersion (small coefficient of variation of tumor G${}_{\mathrm{<mtext>1</mtext><mtext>0</mtext>}}$ populations). For the entire group of patients with malignant disease, three modal values of DNA content were recognized at low-degree hyperdiploidy, near triploidy and tetraploidy. Except for the prevalence of high-degree hyperdiploidy in melanomas and low-degree hyper- and hypodiploid abnormalities in malignant lymphomas, significant disease-specific patterns of abnormal DNA content were not apparent. The magnitude of ploidy abnormality was further influenced by patient age and proliferative activity of the tumor. Female patients displayed a preponderance of small-degree hyperdiploid and tetraploid tumors, whereas near-triploid abnormalities prevailed among male patients, who also harbored five of six biclonal tumors. Tumor cell ploidy did not vary among different sites of disease and upon sequential long-term follow-up examination. All 121 benign tumors had a diploid DNA content. Among the group of 209 patients with normal histology or reactive changes were seven patients with a previously established diagnosis of cancer with ploidy abnormality. This discrepancy indicates that monodispersal of the entire tissue aliquot for DNA flow cytometry is superior to histologic examination of focal neoplasia. There were two patients, one with recurrent benign pleural effusions and one with reactive lymphadenopathy, with ploidy abnormality by DNA content in whom malignant lymphoma developed. We conclude that flow cytometry of cellular DNA content is a rapid, objective, quantitative and sensitive method to determine a highly specific and stable tumor cell marker.     

XIST unmethylated DNA fragments in male-derived plasma as a tumour marker for testicular cancer

Testicular germ-cell tumours (TGCTs) are the most common malignant diseases among men aged 20-40 years. We developed a DNA tumour marker for TGCTs based on the unmethylated DNA profile of a neoplasm. The 5' end of the XIST gene is mainly hypomethylated in TGCTs irrespective of XIST expression. Male somatic cells, however, show complete methylation through the CpG sites, including the minimum promoter and XIST-conserved repeats. Identification of a XIST unmethylated fragment in male plasma might be diagnostic for TGCTs.     

Helicobacter pylori in gastric cancer established by CagA immunoblot as a marker of past infection

BACKGROUND & AIMS: Helicobacter pylori may disappear spontaneously with progressing precancerous changes and invalidate serologic studies of its association with gastric cancer. We reestimated the strength of the H. pylori-gastric cancer relationship, using both conventional immunoglobulin (Ig) G enzyme-linked immunosorbent assay (ELISA) and immunoblot (against cytotoxin-associated antigen A [CagA] antibodies that prevail longer after eradication) to detect past H. pylori exposure more relevant for time at cancer initiation. METHODS: In our population-based case-control study, the seroprevalence among 298 gastric adenocarcinoma cases was 72% (IgG ELISA) and 91% (immunoblot) vs. 55% and 56% among 244 controls frequency-matched for age and gender. RESULTS: Using IgG ELISA only, the adjusted OR for noncardia gastric cancer among H. pylori-positive subjects was 2.2 (95% confidence interval [CI], 1.4-3.6). When ELISA-/CagA+ subjects (odds ratio [OR], 68.0) were removed from the reference, the OR rose to 21.0 (95% CI, 8.3-53.4) and the previous effect modification by age disappeared. ELISA+/CagA- subjects had an OR of 5.0 (95% CI, 1.1-23.6). There were no associations with cardia cancer. CONCLUSIONS: The weaker H. pylori-cancer relationships in studies based on IgG ELISA rather than CagA may be caused by misclassification of relevant exposure. A much stronger relationship emerges with more accurate exposure classification. In the general Swedish population, 71% of noncardia adenocarcinomas were attributable to H. pylori.     

DNA as a marker of cell death in systemic lupus erythematosus

DNA circulates in the blood in systemic lupus erythematosus, among other conditions, and plays a role in immunopathogenesis in the form of immune complexes. As shown in experiments in mice, blood DNA levels rise following treatments to induce apoptosis and the administration of cells made apoptotic or necrotic in vitro. In mice lacking macrophage function, however, blood levels do not rise following administration of dead cells. These results indicate that circulating DNA may be a marker of cell death, although its levels likely reflect a complex process involving the interactions of macrophages with dead and dying cells.     

Plasma DNA level as a tumor marker in primary lung cancer

The plasma level of human DNA was determined by the dot-hybridization method using human Alu-family DNA as a probe in 45 patients with primary lung cancer, 54 patients with benign pulmonary diseases, and 59 healthy controls. The mean plasma DNA level was significantly higher in the patients with lung cancer than that in the patients with benign pulmonary diseases or in healthy controls. The mean plasma DNA level in the patients with benign pulmonary diseases was also significantly higher than that in healthy controls. There was no significant difference in mean plasma DNA level in each histologic type of lung cancer. The plasma DNA level was elevated above the cut-off level of 80 ng/ml in 71% of the patients with lung cancer, 37% of the patients with benign pulmonary diseases and none of the healthy controls. The serum CEA was positive in 38% of the patients with lung cancer and thus when plasma DNA and serum CEA were used in combination, 78% of the cases with lung cancer could be detected by these two markers. In the patients with lung cancer who responded to treatment, the plasma DNA levels were significantly decreased after treatment, while its levels were elevated in the patients whose treatment was unsuccessful. These findings indicate that plasma DNA may be a useful marker in patients with lung cancer.     

Aristaless-like homeobox-4 gene methylation is a potential marker for colorectal adenocarcinomas

BACKGROUND & AIMS: The identification of novel genetic and epigenetic markers indicative of changes in the pathogenesis of colon cancer, along with easier-to-use, more sensitive assay methods, may improve the detection, treatment, and overall prognosis of this malignancy. METHODS: Using methylation-specific arbitrarily primed polymerase chain reaction, a fragment of the Aristaless-like homeobox-4 (ALX4) gene that was highly methylated in colon adenomas and cancer was identified. Methylation of ALX4 was analyzed in colorectal adenomas and cancers, in the liver metastases of patients with colorectal cancer, and in 61 other neoplasias, including gastric, esophageal, and hepatocellular cancer and cholangiocarcinoma. ALX4 methylation was also analyzed in the serum of 30 patients with colon cancer. RESULTS: ALX4 gene methylation was confirmed in colon adenomas (11/13) and more frequently present in primary colorectal cancers (30/47) compared with the normal colon mucosa (0/21) (P < .0001). In addition, ALX4 methylation was frequently observed in adenocarcinomas of the esophagus (12/14), stomach (11/15), and bile ducts (4/5) compared with all other cancers (P < .001). ALX4 gene methylation was also more frequently found in sera of patients with colon cancer compared with noncancer controls (P < .0001). Using a cutoff of 41.4 pg/mL, sensitivity and specificity were 83.3% and 70%, respectively. CONCLUSIONS: Apart from colon adenomas and primary and metastatic colorectal cancers, ALX4 is frequently methylated in adenocarcinomas of the gastrointestinal tract. ALX4 gene methylation in sera of patients with cancer may thus serve as a methylation-specific test for colon and other gastrointestinal cancers.     

Counselling for HIV infection and AIDS: the past and the future

The history of counselling in HIV infection and AIDS is reviewed and the stages in the development of the area are set out. The way in which the area has developed in the West is related to local circumstances and the need for the development of models suited to local circumstances elsewhere in the world is stressed. There are many areas of of HIV/AIDS counselling where considerable uncertainty about the right approach remains, for instance with injecting drug users and with HIV-infected pregnant women. There is a great and largely unmet need for further research in the area and some of the questions which need to be addressed are set out.