The simultaneous presence of a bicarotid trunk and a retroesophageal right subclavian artery: a case report with clinical impact

Many variations exist in the branching pattern of the aortic arch. One variation exists in which there is a common origin of the carotid arteries, known as a bicarotid trunk, coexisting with a retroesophageal right subclavian artery. This anomaly is associated with a right non-recurrent laryngeal nerve. Aortic arch anomalies are clinically applicable to the fields of anatomy, radiology, general medical practice, as well as thoracic and cardiovascular surgery. Here, we report a case of an uncommon branching pattern of the aortic arch identified during anatomical dissection and supported by ante-mortem diagnostic imaging. The anatomical variant was discovered in an 89-year-old Caucasian male during a routine anatomical dissection and was characterized by a bicarotid arterial trunk, left subclavian artery, followed by a retroesophageal right subclavian artery. Additionally, a right non-recurrent inferior laryngeal nerve was present. In the absence of clinical symptoms, the relevance of this variant is most evident in the case of cardiovascular or laryngeal surgeries. With advanced imaging such as CT and MRI, this type of vascular anomaly should be properly identified and described. The variation presented has particular interest to general practitioners, radiologists, and cardiovascular and thoracic surgeons

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The prognostic impact of clinical and molecular features in hairy cell leukaemia variant and splenic marginal zone lymphoma.

Hairy cell leukaemia variant (HCL-variant) and splenic marginal zone lymphoma (SMZL) are disorders with overlapping features. We investigated the prognostic impact in these disorders of clinical and molecular features including IGH VDJ rearrangements, IGHV gene usage and TP 53 mutations. Clinical and laboratory data were collected before therapy from 35 HCL-variant and 68 SMZL cases. End-points were the need for treatment and overall survival. 97% of HCL-variant and 77% of SMZL cases required treatment (P = 0·009). Survival at 5 years was significantly worse in HCL-variant [57% (95% confidence interval 38-73%)] compared with SMZL [84% (71-91%); Hazard Ratio 2·25 (1·20-4·25), P = 0·01]. In HCL-variant, adverse prognostic factors for survival were older age (P = 0·04), anaemia (P = 0·01) and TP 53 mutations (P = 0·02). In SMZL, splenomegaly, anaemia and IGHV genes with >98% homology to the germline predicted the need for treatment; older age, anaemia and IGHV unmutated genes (100% homology) predicted shorter survival. IGHV gene usage had no impact on clinical outcome in either disease. The combination of unfavourable factors allowed patients to be stratified into risk groups with significant differences in survival. Although HCL-variant and SMZL share some features, they have different outcomes, influenced by clinical and biological factors.

The clinical impact and molecular biology of del(17p) in multiple myeloma treated with conventional or thalidomide-based therapy.

Hemizygous deletion of 17p (del(17p)) has been identified as a variable associated with poor prognosis in myeloma, although its impact in the context of thalidomide therapy is not well described. The clinical outcome of 85 myeloma patients with del(17p) treated in a clinical trial incorporating both conventional and thalidomide-based induction therapies was examined. The clinical impact of deletion, low expression, and mutation of TP53 was also determined. Patients with del(17p) did not have inferior response rates compared to patients without del(17p), but, despite this, del(17p) was associated with impaired overall survival (OS) (median OS 26.6 vs. 48.5 months, P < 0.001). Within the del(17p) group, thalidomide induction therapy was associated with improved response rates compared to conventional therapy, but there was no impact on OS. Thalidomide maintenance was associated with impaired OS, although our analysis suggests that this effect may have been due to confounding variables. A minimally deleted region on 17p13.1 involving 17 genes was identified, of which only TP53 and SAT2 were underexpressed. TP53 was mutated in <1% in patients without del(17p) and in 27% of patients with del(17p). The higher TP53 mutation rate in samples with del(17p) suggests a role for TP53 in these clinical outcomes. In conclusion, del(17p) defined a patient group associated with short survival in myeloma, and although thalidomide induction therapy was associated with improved response rates, it did not impact OS, suggesting that alternative therapeutic strategies are required for this group.

Mutational status of the TP53 gene as a predictor of response and survival in patients with chronic lymphocytic leukemia: results from the LRF CLL4 trial.

PURPOSE: TP53 mutations have been described in chronic lymphocytic leukemia (CLL) and have been associated with poor prognosis in retrospective studies. We aimed to address the frequency and prognostic value of TP53 abnormalities in patients with CLL in the context of a prospective randomized trial. PATIENTS AND METHODS: We analyzed 529 CLL samples from the LRF CLL4 (Leukaemia Research Foundation Chronic Lymphocytic Leukemia 4) trial (chlorambucil v fludarabine with or without cyclophosphamide) at the time of random assignment for mutations in the TP53 gene. TP53 mutation status was correlated with response and survival data. RESULTS: Mutations of TP53 were found in 40 patients (7.6%), including 25 (76%) of 33 with 17p deletion and 13 (3%) of 487 without that deletion. There was no significant correlation between TP53 mutations and age, stage, IGHV gene mutations, CD38 and ZAP-70 expression, or any other chromosomal abnormality other than 17p deletion, in which concordance was high (96%). TP53 mutations were significantly associated with poorer overall response rates (27% v 83%; P < .001) and shorter progression-free survival (PFS) and overall survival (OS; 5-year PFS: 5% v 17%; 5-year OS: 20% v 59%; P < .001 for both). Multivariate analysis that included baseline clinical variables, treatment, and known adverse genetic factors confirmed that TP53 mutations have added prognostic value. CONCLUSION: TP53 mutations are associated with impaired response and shorter survival in patients with CLL. Analysis of TP53 mutations should be performed in patients with CLL who have progressive disease before starting first-line treatment, and those with mutations should be selected for novel experimental therapies.

Interlaboratory and interplatform comparison of microarray gene expression analysis of HepG2 cells exposed to benzo(a)pyrene.

Microarray technology is being used increasingly to study gene expression of biological systems on a large scale. Both interlaboratory and interplatform differences are known to contribute to variability in microarray data. In this study we have investigated data from different platforms and laboratories on the transcriptomic profile of HepG2 cells exposed to benzo(a)pyrene (BaP). RNA samples generated in two different laboratories were analyzed using both Agilent oligonucleotide microarrays and Cancer Research UK (CR-UK) cDNA microarrays. Comparability of the expression profiles was assessed at various levels including correlation and overlap between the data, clustering of the data and affected biological processes. Overlap and correlation occurred, but it was not possible to deduce whether choice of platform or interlaboratory differences contributed more to the data variation. Principal component analysis (PCA) and hierarchical clustering of the expression profiles indicated that the data were most clearly defined by duration of exposure to BaP, suggesting that laboratory and platform variability does not mask the biological effects. Real-time quantitative PCR was used to validate the two array platforms and indicated that false negatives, rather than false positives, are obtained with both systems. All together these results suggest that data from similar biological experiments analyzed on different microarray platforms can be combined to give a more complete transcriptomic profile. Each platform gives a slight variation in the BaP-gene expression response and, although it cannot be stated which is more correct, combining the two data sets is more informative than considering them individually.

Gene expression profiles modulated by the human carcinogen aristolochic acid I in human cancer cells and their dependence on TP53.

Aristolochic acid (AA) is the causative agent of urothelial tumours associated with aristolochic acid nephropathy. These tumours contain TP53 mutations and over-express TP53. We compared transcriptional and translational responses of two isogenic HCT116 cell lines, one expressing TP53 (p53-WT) and the other with this gene knocked out (p53-null), to treatment with aristolochic acid I (AAI) (50-100 microM) for 6-48 h. Modulation of 118 genes was observed in p53-WT cells and 123 genes in p53-null cells. Some genes, including INSIG1, EGR1, CAV1, LCN2 and CCNG1, were differentially expressed in the two cell lines. CDKN1A was selectively up-regulated in p53-WT cells, leading to accumulation of TP53 and CDKN1A. Apoptotic signalling, measured by caspase-3 and -7 activity, was TP53-dependent. Both cell types accumulated in S phase, suggesting that AAI-DNA adducts interfere with DNA replication, independently of TP53 status. The oncogene MYC, frequently over-expressed in urothelial tumours, was up-regulated by AAI, whereas FOS was down-regulated. Observed modulation of genes involved in endocytosis, e.g. RAB5A, may be relevant to the known inhibition of receptor-mediated endocytosis, an early sign of AA-mediated proximal tubule injury. AAI-DNA adduct formation was significantly greater in p53-WT cells than in p53-null cells. Collectively, phenotypic anchoring of the AAI-induced expression profiles to DNA adduct formation, cell-cycle parameters, TP53 expression and apoptosis identified several genes linked to these biological outcomes, some of which are TP53-dependent. These results strengthen the importance of TP53 in AA-induced cancer, and indicate that other alterations, e.g. to MYC oncogenic pathways, may also contribute.

Identification through microarray gene expression analysis of cellular responses to benzo(a)pyrene and its diol-epoxide that are dependent or independent of p53.

Human colon carcinoma cells (HCT116) differing in p53 status were exposed to benzo(a)pyrene (BaP) or anti-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE) and their gene expression responses compared by complementary DNA microarray technology. Exposure of cells to BPDE for up to 24 h resulted in gene expression profiles more distinguishable by duration of exposure than by p53 status, although a subset of genes were identified that had significantly different expression in p53 wild-type (WT) cells relative to p53-null cells. Apoptotic signalling genes were up-regulated in p53-WT cells but not in p53-null cells and, consistent with this, reduced viability and caspase activity were also p53 dependent. BPDE modulated cell cycle and histone genes in both cell lines and, in agreement with this, both cell lines accumulated in S phase. In p53-WT cells, G(2) arrest was also evident, which was associated with accumulation of CDKN1A. Regardless of p53 status, exposure to BaP for up to 48 h had subtle effects on gene transcription and had no influence on cell viability or cell cycle. Interestingly, DNA adduct formation after BaP, but not BPDE, exposure was p53 dependent with 10-fold lower levels detected in p53-null cells. Other cell lines were investigated for BaP-DNA adduct formation and in these the effect of p53 knockdown was also to reduce adduct formation. Taken together, these results give further insight into the role of p53 in the response of human cells to BaP and BPDE and suggest that loss of this tumour suppressor can influence the metabolic activation of BaP.

AHR- and DNA-damage-mediated gene expression responses induced by benzo(a)pyrene in human cell lines.

Carcinogens induce complex transcriptional responses in cells that may hold key mechanistic information. Benzo(a)pyrene (BaP) modulation of transcription may occur through the activation of the aryl hydrocarbon receptor (AHR) or through responses to DNA damage. To characterize further the expression profiles induced by BaP in HepG2 and MCF-7 cells obtained in our previous study, they were compared to those induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which activates AHR but does not bind to DNA, and anti-benzo(a)pyrene- trans-7,8-dihydrodiol-9,10-epoxide (BPDE), which binds directly to DNA but does not activate AHR. A total of 22 genes had altered expression in MCF-7 cells after both BaP and TCDD exposure, and a total of 29 genes had altered expression in HepG2 cells. In both cell lines, xenobiotic metabolism was upregulated through induction of NQO1, MGST1, and CYP1B1. A total of 78 expression changes were induced by both BaP and BPDE in MCF-7 cells, and a total of 29 expression changes were induced by both BaP and BPDE in HepG2 cells. These genes were predominantly involved in cell cycle regulation, apoptosis, and DNA repair. BaP and BPDE caused the repression of histone genes in both cell lines, suggesting that regulation of these genes is an important component of the DNA damage response. Interestingly, overlap of the BPDE and TCDD gene expression profiles was also observed. Furthermore, some genes were modulated by BaP but not by TCDD or BPDE, including induction of CRY1 and MAK, which may represent novel signaling pathways that are independent of both AHR activation and DNA damage. Promoter analysis identified candidate genes for direct transcriptional regulation by either AHR or p53. These analyses have further dissected and characterized the complex cellular response to BaP.

Time- and concentration-dependent changes in gene expression induced by benzo(a)pyrene in two human cell lines, MCF-7 and HepG2.

BACKGROUND: The multi-step process of carcinogenesis can be more fully understood by characterizing gene expression changes induced in cells by carcinogens. In this study, expression microarrays were used to monitor the activity of 18,224 cDNA clones in MCF-7 and HepG2 cells exposed to the carcinogen benzo(a)pyrene (BaP) or its non-carcinogenic isomer benzo(e)pyrene (BeP). Time and concentration gene expression effects of BaP exposure have been assessed and linked to other measures of cellular stress to aid in the identification of novel genes/pathways involved in the cellular response to genotoxic carcinogens. RESULTS: BaP (0.25-5.0 muM; 6-48 h exposure) modulated 202 clones in MCF-7 cells and 127 in HepG2 cells, including 27 that were altered in both. In contrast, BeP did not induce consistent gene expression changes at the same concentrations. Significant time- and concentration-dependent responses to BaP were seen in both cell lines. Expression changes observed in both cell lines included genes involved in xenobiotic metabolism (e.g., CYP1B1, NQO1, MGST1, AKR1C1, AKR1C3,CPM), cell cycle regulation (e.g., CDKN1A), apoptosis/anti-apoptosis (e.g., BAX, IER3), chromatin assembly (e.g., histone genes), and oxidative stress response (e.g., TXNRD1). RTqPCR was used to validate microarray data. Phenotypic anchoring of the expression data to DNA adduct levels detected by 32P-postlabelling, cell cycle data and p53 protein expression identified a number of genes that are linked to these biological outcomes, thereby strengthening the identification of target genes. The overall response to BaP consisted of up-regulation of tumour suppressor genes and down-regulation of oncogenes promoting cell cycle arrest and apoptosis. Anti-apoptotic signalling that may increase cell survival and promote tumourigenesis was also evident. CONCLUSION: This study has further characterised the gene expression response of human cells after genotoxic insult, induced after exposure to concentrations of BaP that result in minimal cytotoxicity. We have demonstrated that investigating the time and concentration effect of a carcinogen on gene expression related to other biological end-points gives greater insight into cellular responses to such compounds and strengthens the identification of target genes.

Genome-wide linkage screen for testicular germ cell tumour susceptibility loci.

A family history of disease is a strong risk factor for testicular germ cell tumour (TGCT). In order to identify the location of putative TGCT susceptibility gene(s) we conducted a linkage search in 237 pedigrees with two or more cases of TGCT. One hundred and seventy-nine pedigrees were evaluated genome-wide with an average inter-marker distance of 10 cM. An additional 58 pedigrees were used to more intensively investigate several genomic regions of interest. Genetic linkage analysis was performed with the ALLEGRO software using two model-based parametric analyses and a non-parametric analysis. Six genomic regions on chromosomes 2p23, 3p12, 3q26, 12p13-q21, 18q21-q23 and Xq27 showed heterogeneity LOD (HLOD) scores of greater than 1, with a maximum HLOD of 1.94 at 3q26. Genome-wide simulation studies indicate that the observed number of HLOD peaks greater than one does not differ significantly from that expected by chance. A TGCT locus at Xq27 has been previously reported. Of the 237 pedigrees examined in this study, 66 were previously unstudied at Xq27, no evidence for linkage to this region was observed in this new pedigree set. Overall, the results indicate that no single major locus can account for the majority of the familial aggregation of TGCT, and suggests that multiple susceptibility loci with weak effects contribute to the disease.