RESUMO
Background/Objective: Li-Fraumeni syndrome (LFS) is an inherited sequence variant in TP53 characterized by the early onset of various core malignancies including adrenocortical carcinoma (ACC), sarcomas, breast cancer, leukemias, and central nervous system tumors. We present a case of a patient with LFS who developed endocrine neoplasms not classically seen in LFS in addition to developing ACC. Case Report: A 26-year-old nonbinary individual assigned female at birth with a history of LFS complicated by osteosarcoma of the jaw was incidentally found to have thyroid and sellar masses on surveillance magnetic resonance imaging. Fine-needle aspiration of thyroid mass confirmed papillary thyroid carcinoma, and the patient underwent total thyroidectomy. Pituitary workup was notable for laboratory test results consistent with adrenocorticotropic hormone-dependent hypercortisolism; the patient underwent resection of the pituitary lesion. The patient was subsequently noted on abdominal imaging to have a new left adrenal mass; they underwent left adrenalectomy with pathology consistent with ACC. Discussion: There is limited literature on the relationship between LFS and thyroid and pituitary neoplasms. Genetic testing has suggested that TP53 sequence variants may play a role in tumorigenesis in thyroid and pituitary neoplasms; however, most of the current literature is based on evidence of somatic rather than germline sequence variants. Conclusion: This case highlights a patient with LFS with neoplasia of multiple endocrine organs including ACC, which is a classic finding, as well as papillary thyroid carcinoma and Cushing disease. Further investigation may be necessary to assess if patients with LFS are at a higher risk of various endocrine neoplasms in addition to the core malignancies classically described because this could affect future screening protocols.
RESUMO
Type 2 diabetes is characterized by insulin resistance, hyperglycemia, and progressive ß cell dysfunction. Excess glucose and lipid impair ß cell function in islet cell lines, cultured rodent and human islets, and in vivo rodent models. Here, we examined the mechanistic consequences of glucotoxic and lipotoxic conditions on human islets in vivo and developed and/or used 3 complementary models that allowed comparison of the effects of hyperglycemic and/or insulin-resistant metabolic stress conditions on human and mouse islets, which responded quite differently to these challenges. Hyperglycemia and/or insulin resistance impaired insulin secretion only from human islets in vivo. In human grafts, chronic insulin resistance decreased antioxidant enzyme expression and increased superoxide and amyloid formation. In human islet grafts, expression of transcription factors NKX6.1 and MAFB was decreased by chronic insulin resistance, but only MAFB decreased under chronic hyperglycemia. Knockdown of NKX6.1 or MAFB expression in a human ß cell line recapitulated the insulin secretion defect seen in vivo. Contrary to rodent islet studies, neither insulin resistance nor hyperglycemia led to human ß cell proliferation or apoptosis. These results demonstrate profound differences in how excess glucose or lipid influence mouse and human insulin secretion and ß cell activity and show that reduced expression of key islet-enriched transcription factors is an important mediator of glucotoxicity and lipotoxicity.
Assuntos
Regulação da Expressão Gênica , Proteínas de Homeodomínio/biossíntese , Células Secretoras de Insulina/metabolismo , Transplante das Ilhotas Pancreáticas , Fator de Transcrição MafB/biossíntese , Animais , Xenoenxertos , Proteínas de Homeodomínio/genética , Humanos , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/transplante , Fator de Transcrição MafB/genética , Camundongos , Camundongos KnockoutRESUMO
OBJECTIVE: To study the contribution of interferon-alpha (IFNalpha) and IFNgamma to the IFN gene expression signature that has been observed in microarray screens of peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE). METHODS: Quantitative real-time polymerase chain reaction analysis of healthy control PBMCs was used to determine the relative induction of a panel of IFN-inducible genes (IFIGs) by IFNalpha and IFNgamma. PBMCs from 77 SLE patients were compared with those from 22 disease controls and 28 healthy donors for expression of IFIGs. RESULTS: Expression of IFNalpha-inducible genes was significantly higher in SLE PBMCs than in those from disease controls or healthy donors. The level of expression of all IFIGs in PBMCs from SLE patients with IFNalpha pathway activation correlated highly with the inherent responsiveness of those genes to IFNalpha, suggesting coordinate activation of that cytokine pathway. Expression of genes preferentially induced by IFNgamma was not significantly increased in SLE PBMCs compared with control PBMCs. IFNalpha-regulated gene-inducing activity was detected in some SLE plasma samples. CONCLUSION: The coordinate activation of IFNalpha-induced genes is a characteristic of PBMCs from many SLE patients, supporting the hypothesis that IFNalpha is the predominant stimulus for IFIG expression in lupus.