Publications by authors named "Christine Bonenfant"
Perturbation of the deoxyribonucleotide triphosphate (dNTP) pool is recognized for contributing to the mutagenic processes involved in oncogenesis. The RAS gene family encodes well characterized oncoproteins whose structure and function are among the most frequently altered in several cancers. In this work, we show that fluctuation of the dNTP pool induces CG->TA mutations across the whole genome, including RAS gene at codons for glycine 12 and 13, known hotspots in cancers.
View Article and Find Full Text PDFRecurrent mutations in the CTNNB1 or APC genes leading to the activation of the Wnt/betacatenin pathway are observed in adnexal tumors with matrical differentiation. While most pilomatricomas arise sporadically and harbor CTNNB1 mutations, cutaneous hybrid cysts combining epidermal and matrical differentiations have been mostly reported in a context of the familial adenomatosis polyposis/Gardner's syndrome related to germinal mutations of APC. The objective of this study is to understand the pathogenesis of hybrid cysts combining epidermal and matrical differentiations.
View Article and Find Full Text PDFArticle Synopsis
- The study investigates 16 primary cutaneous carcinomas with mutations in genes that activate the Wnt/β-catenin pathway, noting that these tumors lack matrical differentiation, which is typically associated with such mutations.
- The tumors predominantly affected elderly patients, with a median age of 80, and were mainly located on the head, neck, and upper limbs, leading to metastatic cases in some patients.
- Key findings include poor differentiation in tumor structure, distinct immunohistochemical profiles, and recurrent mutations in APC and CTNNB1, indicating that these tumors represent a unique group apart from other established skin tumor types.
Analyses of combined Merkel cell carcinomas with neuroblastic components suggests that loss of T antigen expression in Merkel cell carcinoma may result in cell cycle arrest and neuroblastic transdifferentiation.
J Pathol
September 2024
Article Synopsis
- - Merkel cell carcinoma (MCC) is an aggressive skin cancer often linked to the Merkel cell polyomavirus, with a rare subtype presenting as combined MCCs featuring an additional tumor component, typically squamous cell carcinoma.
- - This study reports two new cases of combined MCCs with neuroblastic differentiation, characterized by a unique tumor structure involving both a poorly differentiated carcinoma and a neuroblastic component, observed in elderly men with symptoms of isolated inguinal adenopathy.
- - The research utilized various analyses, revealing shared mutations between the tumor components and suggesting that neuroblastic differentiation might occur due to loss of viral protein expression in certain MCC cells, indicating a potential link in their cellular origins.
Background: This study was undertaken to characterize the two porcine lymphoblastoid cell lines L23 and L35, derived from a pig inoculated by the retrovirus Tsukuba-1, and to determine how they induce a strong human lymphocyte proliferation.
Methods: Phenotypic characterization was performed by flow cytometry and reverse transcriptase-polymerase chain reaction analyses. Xenogeneic mixed lymphocyte reactions (XMLR) were performed using unfractionated human peripheral blood mononuclear cells (huPBMC) and purified CD4+ T lymphocytes as responding cells, in the presence of blocking antibodies and fusion proteins.