Vincent L. Biron

Dynamic Changes in Histone H3 Lysine 9 Methylations IDENTIFICATION OF A MITOSIS-SPECIFIC FUNCTION FOR DYNAMIC METHYLATION IN CHROMOSOME CONGRESSION AND SEGREGATION

Histone methylation is unique among post-translational histone modifications by virtue of its stability. It is thought to be a relatively stable and heritable epigenetic mark for gene-specific regulation. In this study, we use quantitative in situ approaches to investigate the cell cycle dynamics of methylated isoforms of histone H3 lysine 9. Contrary to the expected stability of trimethylated lysines, our results for trimethylated lysine 9 (tMeK9) of H3 demonstrate that the genomic content of this methylation undergoes significant changes as cells progress through mitosis. Unexpectedly, there is a loss of tMeK9 that appears to reflect a robust demethylase activity that is active during the period between anaphase and cytokinesis. Subsequent investigations of mitoses in tMeK9-deficient cells revealed defects in chromosome congression and segregation that are distinct from the increased cohesion at centromeres previously reported in association with the loss of tMeK9. Collectively, these results identify a mitosis-specific trimethylation of Lys9 in pericentromeric heterochromatin that functions in the faithful segregation of chromosomes.

Detection of human papillomavirus type 16 in oropharyngeal squamous cell carcinoma using droplet digital polymerase chain reaction.

The incidence of oropharyngeal squamous cell carcinoma caused by oncogenic HPV (HPV‐OPSCC) is rising worldwide. HPV‐OPSCC is commonly diagnosed by RT‐qPCR of HPV‐16 E6 and E7 oncoproteins or by cyclin‐dependent kinase inhibitor 2A, multiple tumor suppressor 1 (p16) immunohistochemistry (IHC). Droplet digital PCR (ddPCR) has been recently reported as ultra‐sensitive and highly precise method of nucleic acid quantification for biomarker analysis. We aimed to validate this method for the detection of HPV‐16 E6 and E7 in HPV‐OPSCC.

Depression and Survival in Patients With Head and Neck Cancer: A Systematic Review

IMPORTANCE The incidence of depression in patients with head and neck cancer (HNC) is estimated to be as high as 40%. Previous studies have demonstrated an effect of depression on rehabilitation and survival in the posttreatment period. OBJECTIVE To systematically review the relationship between depression and survival in patients with HNC undergoing curative treatment. EVIDENCE REVIEW A search of electronic databases as well as gray literature was undertaken from January 1, 1974, to August 20, 2014, including MEDLINE (via Ovid), EMBASE (via Ovid), CINAHL, EBSCO, PsycINFO (via Ovid), Elsevier Scopus, and Institute for Scientific Information Web of Science Core Collection, using controlled vocabulary and medical subject headings representing HNC, depression, and survival. Articles in these databases were reviewed for inclusion by 2 independent reviewers according to predetermined eligibility criteria and were adjudicated by a third reviewer. The articles were then quantitatively scored using the GRACE (Good Research for Comparative Effectiveness) tool, a validated instrument for assessing the quality of observational studies. Qualitative assessment of each article was then undertaken. FINDINGS A total of 654 references were retrieved across all databases. A review of the abstracts and full texts identified 3 articles, each describing a distinct, single study, including a total of 431 patients, that were eligible for analysis. Scores for the articles as assessed with the GRACE tool ranged from 9 to 11. In each of the 3 studies used in the analysis, the comparison groups were depressed and nondepressed patients as established by a standardized psychiatric assessment tool. Two of the 3 studies demonstrated a statistically significant difference in survival for patients with HNC and depression; however, a sensitivity analysis was not possible due to the incompatible statistical analyses performed in each study. CONCLUSIONS AND RELEVANCE An association between depression and survival in patients with HNC is apparent; however, the strength and etiology of this association is not yet clear. Further directed and multi-institutional study is required to investigate this association and determine appropriate screening and management strategies.

Measurement tools for the diagnosis of nasal septal deviation: a systematic review.

ObjectiveTo perform a systematic review of measurement tools utilized for the diagnosis of nasal septal deviation (NSD).MethodsElectronic database searches were performed using MEDLINE (from 1966 to second week of August 2013), EMBASE (from 1966 to second week of August 2013), Web of Science (from 1945 to second week of August 2013) and all Evidence Based Medicine Reviews Files (EBMR); Cochrane Database of Systematic Review (CDSR), Cochrane Central Register of Controlled Trials (CCTR), Cochrane Methodology Register (CMR), Database of Abstracts of Reviews of Effects (DARE), American College of Physicians Journal Club (ACP Journal Club), Health Technology Assessments (HTA), NHS Economic Evaluation Database (NHSEED) till the second quarter of 2013. The search terms used in database searches were ‘nasal septum’, ‘deviation’, ‘diagnosis’, ‘nose deformities’ and ‘nose malformation’. The studies were reviewed using the updated Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.ResultsOnline searches resulted in 23 abstracts after removal of duplicates that resulted from overlap of studies between the electronic databases. An additional 15 abstracts were excluded due to lack of relevance. A total of 8 studies were systematically reviewed.ConclusionsDiagnostic modalities such as acoustic rhinometry, rhinomanometry and nasal spectral sound analysis may be useful in identifying NSD in anterior region of the nasal cavity, but these tests in isolation are of limited utility. Compared to anterior rhinoscopy, nasal endoscopy, and imaging the above mentioned index tests lack sensitivity and specificity in identifying the presence, location, and severity of NSD.

Role of primary surgery in the treatment of advanced oropharyngeal cancer

The purpose of this study was to compare survival outcomes of patients with advanced stage oropharyngeal squamous cell carcinoma (SCC) according to surgical and nonsurgical treatments, when stratified by smoking and p16 status.

Molecular predictors of locoregional and distant metastases in oropharyngeal squamous cell carcinoma

BackgroundThe incidence of oropharyngeal squamous cell carcinoma (OPSCC) is increasing due to fundamental changes in oncogenesis related to effects of the human papilomavirus (HPV). Virally-mediated tumours behave and respond to treatment differently than their classic, carcinogenically-mediated counterparts despite similar stage and grade of disease. This difference in behaviour has lead to investigation of etiologies of OPSCC at the molecular level.Molecular biomarkers offer potential insight into the behaviour of OPSCC. Identifying a subset of patients that are more likely to have recurrence and distant metastasis is valuable for prognostication and treatment planning. There is limited information regarding the profiles of these biomarkers in locoregional and distant metastases in OPSCC.ObjectiveThis study was designed to identify biomarker profiles predictive of locoregional and distant metastases and recurrence in OPSCC.MethodsCross-sectional study of a prospectively-collected oropharyngeal tumour database was undertaken. All patients with OPSCC presenting to the University of Alberta Hospital from 2002- 2009 were included in the study. Data collection from the Alberta Cancer Registry, including demographics, nodal status, distant metastases, treatment, recurrence, and survival, was undertaken. Tissue micro-arrays (TMAs) were constructed for each tumour specimen using triplicate cores (0.6mm) of formalin-fixed, paraffin-embedded (FFPE) pre-treatment tumour tissue. TMAs were processed using immunohistochemistry for p16, EGFR, Ki67, p53, and Bcl-XL. Positivity for each biomarker was determined using quantified AQUAnalysis ® scores on histoplots. Multivariate statistics were utilized to assess the relationship between each biomarker and locoregional and distant metastases, as well as recurrence-free survival (RFS).ResultsHigh expression of p16 (p=0.000) and Bcl-XL (p=0.039) independently demonstrated a significant association with nodal disease at presentation. Kaplan-Meier analysis demonstrated improved RFS in patients with high p16 and decreased RFS in patients with high p53 expression. Cox regression analysis supported p16 as an independent prognosticator for improved RFS. p53 demonstrated an association with recurrence, but when compared to p16 status, nodal status, and staging, was not an independent predictor of recurrence.ConclusionsBiomarker profiling using p16, Bcl-xL, and p53 may be useful in prognostication and treatment planning in patients with OPSCC.

Epigenetics of oropharyngeal squamous cell carcinoma: opportunities for novel chemotherapeutic targets

Epigenetic modifications are heritable changes in gene expression that do not directly alter DNA sequence. These modifications include DNA methylation, histone post-translational modifications, small and non-coding RNAs. Alterations in epigenetic profiles cause deregulation of fundamental gene expression pathways associated with carcinogenesis. The role of epigenetics in oropharyngeal squamous cell carcinoma (OPSCC) has recently been recognized, with implications for novel biomarkers, molecular diagnostics and chemotherapeutics. In this review, important epigenetic pathways in human papillomavirus (HPV) positive and negative OPSCC are summarized, as well as the potential clinical utility of this knowledge.This material has never been published and is not currently under evaluation in any other peer-reviewed publication.

Correlation of PET-CT nodal SUVmax with p16 positivity in oropharyngeal squamous cell carcinoma

BackgroundThe incidence of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) has been rising in recent years. Given the clinical impact of HPV/p16 positivity in OPSCC, identifying surrogate markers of this disease early in the diagnostic work-up of these patients could improve patient care.MethodsDemographic, pathologic, staging and PET-CT data from patients diagnosed with OPSCC from 2009–2014 were obtained from a prospectively collected provincial cancer registry. Tumor HPV/p16 status was correlated to the maximum standard uptake value (SUVmax) of the primary tumor and cervical nodes. Comparisons of means and multinomial regression models were used to determine associations between p16 status and SUVmax. A diagnostic odds ratio was calculated using a cut off value for predicting HPV/p16 positivity based on nodal SUVmax.ResultsPET-CT and HPV/p16 data was obtained for 65 patients treated surgically for OPSCC. Significantly higher nodal SUVmax was associated with HPV/p16 positive nodes (SUVmax 10.8 vs 7.9). No significant differences were seen between HPV/p16 positive vs negative primary tumor SUVmax (10.3 vs 13.7). In combination with other clinical parameters, higher nodal SUVmax was highly correlated with HPV/p16 positivity.ConclusionElevated nodal SUVmax is a significant predictor of HPV/p16 positive disease.

Radial forearm free flap with titanium mesh sandwich reconstruction in complex anterior skull base defects.

Background Skull base reconstruction presents a number of challenges from anatomical and functional perspectives. This is especially the case with large anterior skull base defects with compromised recipient beds from repeated infection, multiple surgeries, or previous radiation. The purpose of the study was to demonstrate the use of the titanium mesh/radial forearm free flap (RFFF) mesh sandwich for reconstruction of large anterior skull base defects with a poor recipient bed or excessive bony defect. Methods Retrospective case series of 3 patients with complex anterior skull base defects reconstructed with a titanium mesh/RFFF mesh sandwich technique. Results Reconstruction of 3 cases using the titanium mesh/RFFF sandwich technique resulted in definitive treatment with no recurrent cerebral spinal fluid leaks, meningitis, or complications. Conclusions The titanium mesh/RFFF sandwich is an excellent reconstructive option for large anterior skull base defects with a poor recipient bed. This approach is facilitated using a combined open and endonasal endoscopic approach in a multidisciplinary team composed of head and neck surgery, rhinology, and neurosurgery.

Ultrasensitive detection of oncogenic human papillomavirus in oropharyngeal tissue swabs

BackgroundThe incidence of oropharyngeal squamous cell carcinoma (OPSCC) caused by oncogenic human papillomavirus (HPV) is rising worldwide. HPV-OPSCC is commonly diagnosed by RT-qPCR of HPV E6 and E7 oncoproteins or by p16 immunohistochemistry (IHC). Droplet digital PCR (ddPCR) has been recently reported as an ultra-sensitive and highly precise method of nucleic acid quantification for biomarker analysis. To validate the use of a minimally invasive assay for detection of oncogenic HPV based on oropharyngeal swabs using ddPCR. Secondary objectives were to compare the accuracy of ddPCR swabs to fresh tissue p16 IHC and RT-qPCR, and to compare the cost of ddPCR with p16 IHC.MethodsWe prospectively included patients with p16+ oral cavity/oropharyngeal cancer (OC/OPSCC), and two control groups: p16− OC/OPSCC patients, and healthy controls undergoing tonsillectomy. All underwent an oropharyngeal swab with ddPCR for quantitative detection of E6 and E7 mRNA. Surgical specimens had p16 IHC performed. Agreement between ddPCR and p16 IHC was determined for patients with p16 positive and negative OC/OPSCC as well as for healthy control patients. The sensitivity and specificity of ddPCR of oropharyngeal swabs were calculated against p16 IHC for OPSCC.Results122 patients were included: 36 patients with p16+OPSCC, 16 patients with p16−OPSCC, 4 patients with p16+OCSCC, 41 patients with p16−OCSCC, and 25 healthy controls. The sensitivity and specificity of ddPCR of oropharyngeal swabs against p16 IHC were 92 and 98% respectively, using 20–50 times less RNA than that required for conventional RT-qPCR. Overall agreement between ddPCR of tissue swabs and p16 of tumor tissue was high at ĸ = 0.826 [0.662-0.989].ConclusionOropharyngeal swabs analyzed by ddPCR is a quantitative, rapid, and effective method for minimally invasive oncogenic HPV detection. This assay represents the most sensitive and accurate mode of HPV detection in OPSCC without a tissue biopsy in the available literature.