Publications by authors named "Simon Roy"

The emergence of pathologist-driven molecular reflex testing for tumoural biomarkers is a significant advancement in cancer diagnostics, facilitating targeted cancer therapy for our patients. Based on our experience, the Canadian landscape of pathologist-driven reflex biomarker testing for melanoma lacks standardization and is plagued by a lack of awareness by pathologists and clinicians. This paper comprehensively examines the approaches to reflex biomarker testing for melanoma patients across Canada, highlighting the regional variations in the criteria for initiating molecular testing, the biomarkers tested, and the molecular techniques employed.

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We studied the exciton delocalization of indodicarbocyanine 5 dye derivative (Cy5-R) heterodimers templated by a DNA Holliday junction (HJ), which was quantified by the exciton hopping parameter . These dyes were modified at the 5 and 5' positions of indole rings with substituent (R) H, Cl, Bu, Peg, and hexyloxy (Hex) groups that exhibit different bulkiness and electron-withdrawing/donating capacities. The substituents tune the physical properties of the dyes, such as hydrophobicity (log ) and solvent-accessible surface area (SASA).

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Correction for 'Towards control of excitonic coupling in DNA-templated Cy5 aggregates: the principal role of chemical substituent hydrophobicity and steric interactions' by Sebastián A. Díaz , , 2023, , 3284-3299. https://doi.

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Article Synopsis
  • Vulvar and vaginal melanomas (VVMs) are rare but serious types of cancer that don't have a lot of standard ways to predict their outcomes.
  • A study looked at 79 cases of VVMs over about 26 months and found that certain factors, like tumour necrosis (when the tumor is dying), can indicate how likely a patient is to survive.
  • Vaginal melanomas were found to have worse survival rates compared to other types like vulvar or clitoral melanomas, highlighting the need for different treatment plans based on where the cancer is located.
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mutation occurs in 46% of melanomas and drives high levels of ERK activity and ERK-dependent proliferation. However, is insufficient to drive melanoma in GEMM models, and 82% of human benign nevi harbor mutations. We show here that BRAF inhibits mesenchymal migration by causing feedback inhibition of RAC1 activity.

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Article Synopsis
  • Some skin cancers, like cutaneous squamous cell carcinoma (cSCC), can look a lot like other harmless conditions, which sometimes leads to mistakes in diagnosis.
  • This study tested a special scoring system for a protein called p53 to help doctors tell cSCC apart from similar-looking but non-dangerous skin issues.
  • The results showed that p53 testing could be a useful tool for doctors, with a high rate of agreement with more advanced testing methods, helping to confirm cSCC diagnoses.
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Molecular aggregates exhibit emergent properties, including the collective sharing of electronic excitation energy known as exciton delocalization, that can be leveraged in applications such as quantum computing, optical information processing, and light harvesting. In a previous study, we found unexpectedly large excitonic interactions (quantified by the excitonic hopping parameter ) in DNA-templated aggregates of squaraine (SQ) dyes with hydrophilic-imparting sulfo and butylsulfo substituents. Here, we characterize DNA Holliday junction (DNA-HJ) templated aggregates of an expanded set of SQs and evaluate their optical properties in the context of structural heterogeneity.

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Programmable self-assembly of dyes using DNA templates to promote exciton delocalization in dye aggregates is gaining considerable interest. New methods to improve the rigidity of the DNA scaffold and thus the stability of the molecular dye aggregates to encourage exciton delocalization are desired. In these dye-DNA constructs, one potential way to increase the stability of the aggregates is to create an additional covalent bond via photo-cross-linking reactions between thymines in the DNA scaffold.

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Distinguishing lupus erythematosus panniculitis (LEP) from subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a diagnostic challenge with important clinical implications. Immunohistochemical expression of interferon regulatory factor 8 (IRF8) has been shown to highlight cells with plasmacytoid dendritic cell differentiation. Considering that the presence of plasmacytoid dendritic cells highlighted by CD123 immunolabeling is a well-described feature that supports LEP over SPTCL, we hypothesized that IRF8 immunohistochemistry can be used as a diagnostic test to improve accuracy in differentiating LEP from SPTCL.

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Aggregates of conjugated organic molecules (i.e., dyes) may exhibit relatively large one- and two-exciton interaction energies, which has motivated theoretical studies on their potential use in quantum information science (QIS).

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We report a series of 58 melanocytic tumors that harbor an activating fusion of BRAF, a component of the mitogen-activated protein kinase (MAPK) signaling cascade. Cases were diagnosed as melanocytic nevus (n = 12, 21%), diagnostically ambiguous favor benign (n = 22, 38%), and diagnostically ambiguous concerning for melanoma (n = 12, 21%) or melanoma (n = 12, 21%). Three main histopathologic patterns were observed.

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Article Synopsis
  • Scientists are trying to tell the difference between two skin issues: one that looks like a harmless grouping of cells and another that is a type of skin cancer called melanoma.
  • They did a study using a special test called PRAME to help identify these differences in skin samples.
  • The results showed that PRAME can be a helpful tool, as it correctly identified the differences between the two conditions most of the time.
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Understanding and controlling exciton coupling in dye aggregates has become a greater focus as potential applications such as coherent exciton devices, nanophotonics, and biosensing have been proposed. DNA nanostructure templates allow for a powerful modular approach. Using DNA Holliday junction (HJ) templates variations of dye combinations and precision dye positions can be rapidly assayed, as well as creating aggregates of dyes that could not be prepared (either due to excess or lack of solubility) through alternative means.

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Molecular excitons are useful for applications in light harvesting, organic optoelectronics, and nanoscale computing. Electronic energy transfer (EET) is a process central to the function of devices based on molecular excitons. Achieving EET with a high quantum efficiency is a common obstacle to excitonic devices, often owing to the lack of donor and acceptor molecules that exhibit favorable spectral overlap.

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