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Cells with loss of BRCA2 function are defective in homologous recombination (HR) and are highly sensitive to inhibitors of poly(ADP-ribose) polymerase (PARP), which provides the basis for a new therapeutic approach. Here we show that resistance to PARP inhibition can be acquired by deletion of a mutation in BRCA2. We derived PARP-inhibitor-resistant (PIR) clones from the human CAPAN1 pancreatic cancer cell line, which carries the protein-truncating c.6174delT frameshift mutation. PIR clones could form DNA-damage-induced RAD51 nuclear foci and were able to limit genotoxin-induced genomic instability, both hallmarks of a competent HR pathway. New BRCA2 isoforms were expressed in the resistant lines as a result of intragenic deletion of the c.6174delT mutation and restoration of the open reading frame (ORF). Reconstitution of BRCA2-deficient cells with these revertant BRCA2 alleles rescued PARP inhibitor sensitivity and HR deficiency. Most of the deletions in BRCA2 were associated with small tracts of homology, and possibly arose from error-prone repair caused by BRCA2 deficiency. Similar ORF-restoring mutations were present in carboplatin-resistant ovarian tumours from c.6174delT mutation carriers. These observations have implications for understanding drug resistance in BRCA mutation carriers as well as in defining functionally important domains within BRCA2. [ABSTRACT FROM AUTHOR]

For individuals genetically predisposed to breast and ovarian cancer through inheritance of a mutant BRCA allele, somatic loss of heterozygosity affecting the wild-type allele is considered obligatory for cancer initiation and/or progression. However, several lines of evidence suggest that phenotypic effects may result from BRCA haploinsufficiency. Archival fixed and embedded tissue specimens from women with germ line deleterious mutations in BRCA1 or BRCA2 were identified. After pathologic review, focal areas of normal breast epithelium, atypical ductal hyperplasia, ductal carcinoma-in-situ, and invasive ductal carcinoma were identified from 14 BRCA1-linked and 9 BRCA2-linked breast cancers. Ten BRCA-linked prophylactic mastectomy specimens and 12 BRCA-linked invasive ovarian carcinomas were also studied. Laser catapult microdissection was used to isolate cells from the various pathologic lesions and corresponding normal tissues. After DNA isolation, real-time polymerase chain reaction assays were used to quantitate the proportion of wild-type to mutant BRCA alleles in each tissue sample. Quantitative allelotyping of microdissected cells revealed a high level of heterogeneity in loss of heterozygosity within and between preinvasive lesions and invasive cancers from BRCA1 and BRCA2 heterozygotes with breast cancer. In contrast, all BRCA-associated ovarian cancers displayed complete loss of the wild-type BRCA allele. These data suggest that loss of the wild-type BRCA allele is not required for BRCA-linked breast tumorigenesis, which would have important implications for the genetic mechanism of BRCA tumor suppression and for the clinical management of this patient population. [ABSTRACT FROM AUTHOR]

Objectives: To determine whether focused abdominal sonogram for trauma (FAST) in a rural hospital provides information that prompts immediate transfer to a tertiary care facility for patients with blunt abdominal trauma who would otherwise be discharged or held for observation. Methods: Prior to the study, participating emergency physicians underwent a minimum of 30 hours of ultrasound training. All patients who presented with blunt abdominal trauma to our rural hospital between Mar. 1, 2002, and Apr. 30, 2003, were eligible for study. Following a history and physical examination, the emergency physician documented his or her disposition decision. A FAST was then performed, and the disposition reconsidered in light of the FAST results. Results: Sixty-seven FAST exams were performed on 65 patients. Three examinations (4.5%) were true-positive (95% confidence interval [CI] 0.9%-12.5%); 60 (89.6%) were true-negative (95% CI 79.7%-95.7%), 4 (6%) were false-negative (95% CI 1.7%-14.6%) and none (0%) were false-positive (95% CI 0%-5.4%). These values reflect sensitivity, specificity, negative predictive value and positive predictive values of 43%, 100%, 94% and 100% respectively. FAST results did not alter the decision to transfer any patient (0%: 95% CI 0.0%-5.4%), although one positive FAST may have led to an expedited transfer. One of 38 patients who was discharged after a negative FAST study returned 24 hours later because of worsening symptoms, and was ultimately found to have splenic and pancreatic injuries. Conclusions: This study failed to demonstrate that FAST improves disposition decisions for patients with blunt abdominal trauma who are evaluated in a hospital without advanced imaging or on-site surgical capability. However, the study is not sufficiently powered to rule out a role for FAST in these circumstances, and our data suggest that up to 5.4% of transfer decisions could be influenced by FAST. Rural emergency physicians should not allow a negative FAST study to override a clinical indication for transfer to a trauma centre; however, positive FAST studies can be used to accelerate transfer for definitive treatment. [ABSTRACT FROM AUTHOR]

Examines whether emergency physicians can accurately diagnose clavicle fractures. Results showing that experienced emergency physicians are highly accurate when they are clinically certain of clavicle fracture; No apparent effect of routine radiography of obvious middle-third clavicle fractures on improving the diagnostic accuracy or treatment decisions.

Objective: Research has demonstrated that experienced emergency physicians can identify a subgroup of patients with shoulder dislocation for whom pre-reduction radiographs do not alter patient management. Based on that research, a treatment guideline for the selective elimination of pre-reduction radiographs in clinically evident cases of anterior shoulder dislocation was developed and implemented. The primary objective of this study was to prospectively determine whether the treatment guideline safely eliminates unnecessary radiographs. Methods: We enrolled a convenience sample of patients who presented to our rural emergency department with possible shoulder dislocation between November 2000 and April 2001. Physiclans scored their level of clinical diagnostic certainty on a 10-cm visual analogue scale prior to viewing pre-reduction radiographs (if obtain). Data were collected on clinical scoring and evaluation, compliance with the guideline, and outcomes. Results: A total of 63 patients were enrolled, ranging in age from 17 to 79 years (mean = 33); 87.3% were male. Emergency physicians were certain of shoulder dislocation in 59 (93.7%) patients (95% CI, 84.5%-98.2%) and complied with the treatment guideline in 52 patients (82.5%). Most deviations from the treatment guideline involved the elimination of post-reduction radiographs (which the guideline recommends for all patients). The treatment guideline eliminated 56 (88.9%, 95% CI, 78.4%-95.4%) pre-reduction radiographs, as compared to the standard practice of obtaining pre-reduction films for all cases of suspected shoulder dislocation (p < 0.0001) Conclusions: Experienced emergency physicians are frequently certain of the diagnosis of anterior shoulder dislocation on clinical grounds alone and can comfortably and safely use this guideline for the selective elimination of pre-reduction radiographs. Compliance with the guideline substantially decreases pre-reduction radiographs. Validation of the guideline in... [ABSTRACT FROM AUTHOR]

A male member of a large HNPCC kindred, affected by primary malignancies of the breast and colon, was identified. This individual was found to harbor a germline mutation of the MLH1 mismatch repair gene previously shown to segregate with disease in this kindred. The breast tumor exhibited somatic reduction to homozygosity for the MLH1 mutation, and microsatellite instability was evident in the breast tumor. We conclude that hereditary male breast cancer can occur as an integral tumor in the HNPCC syndrome. [ABSTRACT FROM AUTHOR]

Neonatal treatment with estrogens is associated with development of uterine adenocarcinomas in CD-1 mice. Treatment with the synthetic estrogen diethylstilbestrol (DES) on Days 1 to 5 after birth results in 90% incidence of these hormonedependent lesions in 18-mo.-old mice. Three cell lines were established from these DES-associated tumors. Each of these cell lines exhibited morphologic and ultrastructural characteristics of transformed epithelial cells, including an increased nuclear:ytoplasmic ratio, enlarged and irregular nuclei with multiple nucleoli and areas of chromatin condensation, positive staining for cytokeratin, desmosomes, and microvilli. After subcutaneous injection into nude mice, all three cell lines formed solid tumors within 4 wk. Although the primary uterine tumors and tumor transplants in nude mice had been shown to be estrogen-dependent and estrogen-receptor positive, neither the monolayer growth nor the tumorigenicity of any of the three cell lines in this study was enhanced by or dependent on estrogen. Estrogen receptor levels were low in early and intermediate passage cells. Allele-specific oligonucleotide hybridization analysis of PCR-amplified cell line DNA revealed no point mutations in the 12th, 13th, or 61st codons of the K-ras or H-ras protooncogenes. Southern analysis revealed no changes in genomic organization of the putative tumor suppressor gene DCC, but demonstrated a three-to four-fold amplification of the c-myc gene in one cell line. Expression of c-myc RNA was concomitantly increased in the same cell line. These three transformed cell lines represent the end point in the process of hormone-associated tumorigenesis and as such should prove useful in investigating the molecular changes and the mechanisms involved in hormonal carcinogenesis. [ABSTRACT FROM AUTHOR]

Two new lines of human endometrial carcinoma (HEC) cells, one from an adenocarcinoma and one from a highly metastatic serous papillary carcinoma, were established in culture. Structural and morphologic properties of these cells at early passage were compared with those of cultured normal human endometrial epithelial (NHEE) cells. For these studies, cells were grown on a conventional plastic surface or on an extracellular matrix substrate (Matrigel), and examined by transmission electron microscopy and immunofluorescent light microscopy. The HEC cells appeared morphologically similar on plastic and Matrigel, whereas the NHEE cells showed significantly greater epithelial morphologic differentiation on Matrigel than on plastic. On extracellular matrix, the morphologic differences observed between HEC cells and NHEE cells were primarily of an architectural nature, which may be in part explained by differences between NHEE and HEC cells in the arrangement of actin microfilaments and cytokeratin intermediate filaments. Furthermore, HEC cells displayed extensive networks of vimentin intermediate filaments, which were absent from the NHEE cells. These observations support the hypothesis that architectural deregulation is a prominent feature of endometrial carcinoma, and that cytoskeletal alterations may uncouple HEC cell ultrastructural morphology from the influence of extracellular matrix. [ABSTRACT FROM AUTHOR]