Noelyn Hung

Hyperproliferation, cancer, and inflammation in mice expressing a Δ133p53-like isoform

The p53 protein is a pivotal tumor suppressor that is frequently mutated in many human cancers, although precisely how p53 prevents tumors is still unclear. To add to its complexity, several isoforms of human p53 have now been reported. The Δ133p53 isoform is generated from an alternative transcription initiation site in intron 4 of the p53 gene (Tp53) and lacks the N-terminus. Elevated levels of Δ133p53 have been observed in a variety of tumors. To explore the functions of Δ133p53, we created a mouse expressing an N-terminal deletion mutant of p53 (Δ122p53) that corresponds to Δ133p53. Δ122p53 mice show decreased survival and a different and more aggressive tumor spectrum compared with p53 null mice, implying that Δ122p53 is a dominant oncogene. Consistent with this, Δ122p53 also confers a marked proliferative advantage on cells and reduced apoptosis. In addition to tumor development, Δ122p53 mice show a profound proinflammatory phenotype having increased serum concentrations of interleukin-6 and other proinflammatory cytokines and lymphocyte aggregates in the lung and liver as well as other pathologies. Based on these observations, we propose that human Δ133p53 also functions to promote cell proliferation and inflammation, one or both of which contribute to tumor development.

Hematuria and death secondary to aortoureteric fistula

Ureteroarterial fistulae are extremely rare after previous vascular surgery. Eight cases have been described in the English literature. This is the first example of a vascular communication between the aorta and the ureter. All previous cases were ureteroiliac fistulae. Known hydronephrosis in the presence of prior vascular grafting and heavy hematuria should alert the clinician to the possibility of a ureteroarterial fistula.

The CDKN2A G500 Allele Is More Frequent in GBM Patients with No Defined Telomere Maintenance Mechanism Tumors and Is Associated with Poorer Survival

Prognostic markers for glioblastoma multiforme (GBM) are important for patient management. Recent advances have identified prognostic markers for GBMs that use telomerase or the alternative lengthening of telomeres (ALT) mechanism for telomere maintenance. Approximately 40% of GBMs have no defined telomere maintenance mechanism (NDTMM), with a mixed survival for affected individuals. This study examined genetic variants in the cyclin-dependent kinase inhibitor 2A (CDKN2A) gene that encodes the p16INK4a and p14ARF tumor suppressors, and the isocitrate dehydrogenase 1 (IDH1) gene as potential markers of survival for 40 individuals with NDTMM GBMs (telomerase negative and ALT negative by standard assays), 50 individuals with telomerase, and 17 individuals with ALT positive tumors. The analysis of CDKN2A showed NDTMM GBMs had an increased minor allele frequency for the C500G (rs11515) polymorphism compared to those with telomerase and ALT positive GBMs (p = 0.002). Patients with the G500 allele had reduced survival that was independent of age, extent of surgery, and treatment. In the NDTMM group G500 allele carriers had increased loss of CDKN2A gene dosage compared to C500 homozygotes. An analysis of IDH1 mutations showed the R132H mutation was associated with ALT positive tumors, and was largely absent in NDTMM and telomerase positive tumors. In the ALT positive tumors cohort, IDH1 mutations were associated with a younger age for the affected individual. In conclusion, the G500 CDKN2A allele was associated with NDTMM GBMs from older individuals with poorer survival. Mutations in IDH1 were not associated with NDTMM GBMs, and instead were a marker for ALT positive tumors in younger individuals.

Ascending-dose study of noribogaine in healthy volunteers: Pharmacokinetics, pharmacodynamics, safety, and tolerability

Noribogaine is the active metabolite of the naturally occurring psychoactive substance ibogaine, and may help suppress withdrawal symptoms in opioid‐dependent subjects. The objectives of this Phase I study were to assess the safety, tolerability, pharmacokinetic, and pharmacodynamic profiles of noribogaine. In this ascending single‐dose, placebo‐controlled, randomized, double‐blind, parallel‐group study in 36 healthy drug‐free male volunteers, 4 cohorts (n = 9) received oral doses of 3, 10, 30, or 60 mg or matching placebo, with intensive safety and pharmacokinetic assessments out to 216 hours, along with pharmacodynamic assessments sensitive to the effects of mu‐opioid agonists. Noribogaine was rapidly absorbed, with peak concentrations occurring 2–3 hours after oral dosing, and showed dose‐linear increases of area under the concentration–time curve (AUC) and Cmax between 3 and 60 mg. The drug was slowly eliminated, with mean half‐life estimates of 28–49 hours across dose groups. Apparent volume of distribution was high (mean 1417–3086 L across dose groups). No safety or tolerability issues were identified in any cohort. No mu‐opioid agonist pharmacodynamic effects were noted in pupillometry or cold‐pressor testing. Single oral doses of noribogaine 3–60 mg were safe and well tolerated in healthy volunteers.

Bilateral, uncemented total hip arthroplasty in osteopetrosis

Bilateral, uncemented hip replacements were performed on a 45-year-old woman with autosomal dominant osteopetrosis. The hips showed degenerative changes and protrusio acetabuli. Difficulties were encountered especially during preparation of the femoral canal. At ten-year follow-up she has an excellent clinical and radiological result with no sign of osteolysis. Uncemented hip replacement, while technically demanding, can be successful in the intermediate term for patients with this condition.

The alternative lengthening of telomeres pathway may operate in non-neoplastic human cells†

The alternative lengthening of telomeres (ALT) mechanism represents an alternative to the enzyme telomerase in the maintenance of mammalian telomeres in 25–60% of sarcomas and a minority of carcinomas (about 5–15%). ALT‐positive cells are distinguished by long and heterogeneous telomere length distributions by terminal restriction fragment (TRF) Southern blotting. Another diagnostic marker of ALT is discrete nuclear co‐localized signals of telomeric DNA and the promyelocytic leukaemia protein (PML), referred to as ALT‐associated PML bodies (APBs). Recently, we detected smaller sized co‐localized PML and telomere DNA (APB‐like) bodies in endothelial cells adjacent to astrocytoma tumour cells in situ. In this study, we examined a wide variety of non‐neoplastic tissues, and report that co‐localized signals of PML and telomere DNA are present in endothelial, stromal, and some epithelial cells. Co‐localized signals of PML and telomere DNA showed an increased frequency in non‐neoplastic cells with DNA damage. These results suggest that a mechanism similar to that in ALT‐positive tumours also operates in non‐neoplastic cells, which may be activated by DNA damage. Copyright

Prognostic Association of YB-1 Expression in Breast Cancers: A Matter of Antibody

The literature concerning the subcellular location of Y-box binding protein 1 (YB-1), its abundance in normal and cancer tissues, and its prognostic significance is replete with inconsistencies. An explanation for this could be due in part to the use of different antibodies in immunohistochemical and immunofluorescent labeling of cells and tissues. The inconsistencies could also be due to poor resolution of immunohistochemical data. We analyzed two cohorts of breast tumours for both abundance and subcellular location of YB-1 using three different antibodies; two targeting N-terminal epitopes (AB- a and AB- b) and another (AB- c) targeting a C-terminal epitope. We also investigated stress-induced nuclear translocation of YB-1 in cell culture. We report that both AB- a and AB- c detected increased YB-1 in the cytoplasm of high-grade breast cancers, and in those lacking estrogen and progesterone receptors; however the amount of YB-1 detected by AB- a in these cancers is significantly greater than that detected by AB- c. We confirm our previously published findings that AB- b is also detecting hnRNP A1, and cannot therefore be used to reliably detect YB-1 by immunohistochemistry. We also report that AB- a detected nuclear YB-1 in some tumour tissues and stress treated cells, whereas AB- c did not. To understand this, cancer cell lines were analyzed using native gel electrophoresis, which revealed that the antibodies detect different complexes in which YB-1 is a component. Our data suggest that different YB-1 antibodies show different staining patterns that are determined by the accessibility of epitopes, and this depends on the nature of the YB-1 complexes. It is important therefore to standardize the protocols if YB-1 is to be used reproducibly as a prognostic guide for different cancers.

A clinicopathological study of episomal papillomavirus infection of the human placenta and pregnancy complications.

Viral infections are known to adversely affect pregnancy, but scant attention has been given to human papilloma virus (HPV) infection. We aimed to determine the molecular and histopathological features of placental HPV infection, in association with pregnancy complications including fetal growth restriction, pre-maturity, pre-eclampsia, and diabetes. Three hundred and thirty-nine placentae were selected based on the presence or absence of pregnancy complications. Five independent methods were used to identify HPV in the placenta, namely, immunohistochemistry for L1 viral capsid, in situ hybridization to high-risk HPV DNA, PCR, western blotting, and transmission electron microscopy. Pregnancy complications and uterine cervical smear screening results were correlated with placental HPV histopathology. In this study, which was deliberately biased towards complications, HPV was found in the decidua of 75% of placentae (253/339) and was statistically associated with histological acute chorioamnionitis (P<0.05). In 14% (35/253) of the HPV positive cases, HPV L1 immunoreactivity also occurred in the villous trophoblast where it was associated with a lymphohistiocytic villitis (HPV-LHV), and was exclusively of high-risk HPV type. HPV-LHV significantly associated with fetal growth restriction, preterm delivery, and pre-eclampsia (all P<0.05). All cases of pre-eclampsia (20/20) in our cohort had high-risk placental HPV. A further 55 cases (22%, 55/253) of HPV positive placentae had minimal villous trophoblast HPV L1 immunoreactivity, but a sclerosing pauci-immune villitis, statistically associated with diabetes (49.1%, 27/55, P<0.05). For women with placental HPV, 33% (69/207) had an HPV-related positive smear result before pregnancy compared with (9.4% 8/85) of women with HPV-negative placentae (P=0.0001). Our findings support further investigations to determine if vaccination of women and men will improve pregnancy outcomes.

Late intramedullary spinal cord metastasis in a patient with lymphoblastic lymphoma: case report

Late intramedullary spinal cord metastasis of lymphoblastic lymphoma (LBL) is unreported in the literature. The central nervous system (CNS) sites of metastasis previously documented include the spinal leptomeninges causing epidural spinal cord compression or brain praenchymal sites within a year of primary diagnosis. This report represents the first case of intramedullary spinal cord LBL as a late recurrence. The method consists of a case study of one patient with retrospective analysis of tumour tissues from biopsies at ages 5, 9 and 26. The results show that late spinal cord recurrence was microneurosurgically subtotally debulked and later treated with radiotherapy with improvement in neurological deficit. Investigations revealed no evidence of systemic disease and this recurrence appears to be an isolated sanctuary site tumour. A MEDLINE search (1966 - present) of the literature failed to reveal similar reported cases and the authors believe this to be the first late intramedullary spinal cord metastasis in a patient with LBL.

The rs11515 Polymorphism Is More Frequent and Associated With Aggressive Breast Tumors with Increased ANRIL and Decreased p16INK4a Expression

Chromosome position 9p21 encodes three-tumor suppressors p16INK4a, p14ARF, and p15INK4b and the long non-coding RNA ANRIL (antisense non-coding RNA in the INK4 locus). The rs11515 single-nucleotide polymorphism in the p16INK4a/p14ARF 3′-untranslated region is associated with glioblastoma, melanoma, and other cancers. This study investigated the frequency and effect of rs11515 genotypes in breast cancer. Genomic DNA samples from 400 women (200 with and 200 without a diagnosis of breast cancer) were genotyped for the rs11515 major (C) and minor (G) alleles. The rs11515 polymorphism was also investigated in 108 heart tissues to test for tissue-specific effects. Four 9p21 transcripts, p16INK4a, p14ARF, p15INK4b, and ANRIL were measured in breast tumors and myocardium using quantitative PCR. Heterozygotes (CG genotype) were more frequent in women with breast cancer compared to the control population (P = 0.0039). In those with breast cancer, the CG genotype was associated with an older age (P = 0.016) and increased lymph node involvement (P = 0.007) compared to homozygotes for the major allele (CC genotype). In breast tumors, the CG genotype had higher ANRIL (P = 0.031) and lower p16INK4a (P = 0.006) expression compared to the CC genotype. The CG genotype was not associated with altered 9p21 transcripts in heart tissue. In breast cancer, the rs11515 CG genotype is more frequent and associated with a more aggressive tumor that could be due to increased ANRIL and reduced p16INK4a expression. The absence of association between rs11515 genotypes and 9p21 transcripts in heart tissue suggests this polymorphism has tissue- or disease-specific functions.