Unique genetic profile of sporadic colorectal cancer liver metastasis versus primary tumors as defined by high-density single-nucleotide polymorphism arrays.

Most genetic studies in colorectal carcinomas have focused on those abnormalities that are acquired by primary tumors, particularly in the transition from adenoma to carcinoma, whereas few studies have compared the genetic abnormalities of primary versus paired metastatic samples. In this study, we used high-density 500K single-nucleotide polymorphism arrays to map the overall genetic changes present in liver metastases (n=20) from untreated colorectal carcinoma patients studied at diagnosis versus their paired primary tumors (n=20). MLH1, MSH2 and MSH6 gene expression was measured in parallel by immunohistochemistry. Overall, metastatic tumors systematically contained those genetic abnormalities observed in the primary tumor sample from the same subject. However, liver metastases from many cases (up to 8 out of 20) showed acquisition of genetic aberrations that were not found in their paired primary tumors. These new metastatic aberrations mainly consisted of (1) an increased frequency of genetic lesions of chromosomes that have been associated with metastatic colorectal carcinoma (1p, 7p, 8q, 13q, 17p, 18q, 20q) and, more interestingly, (2) acquisition of new chromosomal abnormalities (eg, losses of chromosomes 4 and 10q and gains of chromosomes 5p and 6p). These genetic changes acquired by metastatic tumors may be associated with either the metastatic process and/or adaption of metastatic cells to the liver microenvironment. Further studies in larger series of patients are necessary to dissect the specific role of each of the altered genes and chromosomal regions in the metastatic spread of colorectal tumors.

Immunohistochemical expression of p53 in breast carcinoma is associated with the intron 1 BglII polymorphism of the p53 gene.

Breast carcinoma is a public health problem worldwide. It is known that both genetic and environmental factors are important for breast carcinogenesis and that structural and/or functional alterations at p53 gene are commonly observed in breast tumors. In addition, polymorphisms of several genes in either their coding or non-coding sequences have been found related to cancer risk and/or clinicopathological characteristics of tumors. In this study we have evaluated the intron 1 BglII polymorphism of the p53 gene with a PCR-based approach in 117 cases of breast cancer and 102 healthy women and its association with the immunohistochemical expression of p53 in the tumors. The results showed that the presence of the polymorphism (allele 2) is highly associated with the tumor expression of p53 (p<0.0001) and that there is a trend for increased frequency of allele 2 in cases than in controls (p=0.2376). These data suggest that the germ-line variation in the intron 1 of the p53 gene could produce functional or structural changes of the protein that is reflected by its abnormal expression.

Human insulin B chain but not A chain decreases the rate of diabetes in BB rats.

The autoimmune response seen in insulin-dependent diabetes mellitus (IDDM) includes a humoral immune response against human insulin. Early insulin treatment has been used to prevent IDDM in the rodent models of IDDM, and a prevention trial is underway in humans. The metabolic effects of insulin may not be involved in this prevention since, in NOD mice, the use of metabolically inert human insulin B chain was effective. We wished to ascertain whether immunization of diabetes-prone BB/W rats with insulin B chain, A chain, or both could alter the incidence of diabetes. Immunizations began by 30 days of age and the rats were followed until 120 days of age. Only immunization with insulin B chain plus adjuvant was effective in reducing the rate of diabetes. All immunization frequencies were effective, but a significantly lower rate of diabetes was achieved with injections every week. All of the doses tested resulted in significantly lower rates of diabetes. These data confirm in the BB rat model that immunization with insulin B chain in the presence of adjuvant can reduce diabetes incidence. The absence of any metabolic effect of B chain and the requirement for adjuvant suggest that this effect is mediated via modulation of the autoimmune response.

Screening for the mitochondrial DNA A3243G mutation in children with insulin-dependent diabetes mellitus.

Since recent studies demonstrated the occurrence of the mitochondrial DNA (mtDNA) mutation A3243G in patients with adult-onset diabetes, an investigation was undertaken to determine the frequency of this mutation in a pediatric population with insulin-dependent diabetes mellitus (IDDM). DNA was extracted from peripheral blood of 270 pediatric patients with IDDM. The presence of the mtDNA A3243G mutation was screened for by minisequencing and mutation-specific ApaI endonuclease restriction after polymerase chain reaction (PCR) amplification of mtDNA. The A3243G mtDNA mutation was not found in any IDDM patients examined. This mutation is uncommon in children with IDDM from various ethnic and racial groups. Therefore, the contribution of the mutation to the pathogenesis of IDDM, if any, is minimal.

Duodenal leishmaniasis diagnosed by biopsy in two HIV-positive patients.

We describe two cases of duodenal leishmaniasis in patients with human immunodeficiency virus (HIV) infection, diagnosed by light and electron microscopy. The patients presented nonspecific signs and symptoms, blood cultures were sterile, and serological tests for Leishmania spp. were negative. Endoscopy showed normal-appearing mucosa in one patient and possible peptic duodenitis in the other patient. In these patients, the parasite was only detected in a duodenal biopsy specimen. In view of the unusual location of the parasite and the fact that the diagnostic and dissemination of the disease was established by means of conventional biopsy, this is not a routine procedure for the diagnosis of leishmaniasis because the classic procedures require the demonstration of antibodies and visualization in bone marrow, lymph nodes, liver and/or spleen aspirates. We decided to report these two cases to call attention to the possible finding of Leishmania amastigotes in biopsies from intestinal mucosa in HIV infected patients.

Usefulness of antral brushing samples stained with Diff-Quik in the cytologic diagnosis of Helicobacter pylori. A comparative methodologic study.

We studied the usefulness of antral cytologic specimens obtained by brushing and stained with Diff-Quik in the diagnosis of gastric colonization by Helicobacter pylori in 102 patients, comparing this method with other commonly employed techniques. We report on the sensitivity, specificity, predictive value for positive and negative cases of each of the techniques used, and diagnostic problems posed by each. In general, the Diff-Quik-stained samples proved to be the most useful. This technique is a simple, economical and practical method for the diagnosis of gastric colonization by H pylori.

Statistical evaluation of the predictive power of fine needle aspiration (FNA) of salivary glands. Results and cytohistological correlation.

Fine needle aspiration (FNA) of the salivary glands was carried out on 97 patients. Diagnosis was confirmed by histological findings in 93 patients. There were 75 benign lesions (including 52 benign tumours) and 18 malignant lesions. In our series "positive predictive value" of FNA was 0.900 and the negative predictive value was 0.963. Thus, the probability of a false positive is 0.100 and of a false negative 0.037.

Comparative study of in situ hybridization and immunohistochemical techniques for the detection of human papillomavirus in lesions of the uterine cervix.

Among the techniques currently used for the detection of human papillomavirus (HPV) in genital lesions, only two correlate HPV with the histopathological findings of the lesion: immunohistochemistry and in situ hybridization. Consequently, we were prompted to carry out a comparative study on both techniques to check their utility and efficacy as routine diagnostic methods. 52 biopsy specimens of uterine cervix diagnosed histopathologically as condylomas and cervical intraepithelial neoplasia+koilocytosis were studied by immunohistochemical and in situ hybridization techniques using a polyclonal antibody against the common antigen of the HPV capsid and three biotinylated DNA probes specific to HPV types 6/11, 16/18 and 31/35/51. Immunohistochemistry detected 21 positive cases (40.38%), whereas in situ hybridization detected 40 positive cases (76.92%); of the latter, 30 were positive for HPV types 6/11, 3 for HPV types 16/18 and 11 for HPV types 31/35/51. The results suggest that in situ hybridization is a more sensitive technique than immunohistochemistry. However, we recommend the use of both techniques in the case of potentially malignant lesions since better prognostic information can be obtained from joint analysis of both results.

Modifications of "A cells" in the development of experimentally induced pancreatic ductal adenocarcinoma: an ultrastructural and immunohistochemical study.

In the hamster-BOP model, modifications occur in the endocrine portion of the pancreas during the induction of well-differentiated ductal carcinomas. In the present work, using immunohistochemical techniques it was possible to observe that the A cells in preserved islets and in the initial phase of the carcinogenic process were localized in the peripheral part of the islets. In animals with tumours, A cells were found to form part of the tumour glands and/or the tumoral stroma; this localization was seen to depend on the developmental phase of the tumour. A focal dispersion of A cells was observed in the animals with ductal carcinoma.

Study of infection by human papillomavirus in severe dysplasias and carcinomas in situ of the uterine cervix using immunohistochemistry and in situ hybridization.

Diagnosis of human papillomavirus (HPV) infection in uterine cervical lesions is usually based on histopathological criteria and, in some cases, is confirmed by immunohistochemistry. The recent development of in situ hybridization techniques has facilitated the detection of HPV in these lesions. Consequently, we carried out a study on 18 uterine cervical biopsy specimens histopathologically diagnosed as severe dysplasias and carcinomas in situ, using an immunohistochemical method with a rabbit polyclonal antibody against the HPV common structural antigen and in situ hybridization techniques with three biotinylated DNA probes for HPV types 6/11, 16/18, and 31/35/51. By immunohistochemistry only one case (5.5%) proved to be positive, whereas by in situ hybridization 12 HPV-positive cases were obtained (66.6%), of which 7 were positive for HPV types 16/18 (38.8%) and 6 for HPV types 31/35/51 (33.3%). One case was positive with positive with both DNA probes. From our results it can be inferred that in situ hybridization is a more sensitive technique than immunohistochemistry for confirming the presence of HPV in severe dysplasias and carcinomas in situ of the uterine cervix. Furthermore, in situ hybridization provides much more information than immunohistochemistry since it permits the identification of the HPV types causing the lesion.

Chronic gastritis associated with Helicobacter pylori. Correlation between histological and bacteriological findings.

Biopsy specimens of gastric and duodenal mucosa from 326 patients were examined bacteriologically and histologically to determine the correlation between chronic gastritis and H. pylori colonization. H. pylori was identified in 111 (66.5%) patients with evidence of chronic gastritis and in 97 (82.2%) individuals who had gastritis associated with other pathology (gastric o duodenal ulcer, carcinoma o bulboduodenitis). The spiral bacteria was found more frequently in specimens with chronic superficial gastritis (88/107) and no significant difference was observed between the grade of activity of gastritis and H. pylori colonization. Giemsa stain was the most suitable method for detecting H. pylori in histological sections. By electron microscopy the microorganism was seen on the surface of the gastric mucosa, beneath the mucous layer, and more occasionally in intercellular junctions and the gastric pit.