system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Cell Line, Tumor, Disease Models, Animal, Enzyme Inhibitors, Female, Head and Neck Neoplasms, Indazoles, Longitudinal Studies, Lymphoma, B-Cell, Lymphoma, Follicular, Magnetic Resonance Imaging, Mice, Mice, Inbred C57BL, Mice, Transgenic, PTEN Phosphohydrolase, Phosphatidylinositol 3-Kinases, Sulfonamides.
user
Does quantitative MRI establish the efficacy of PI3K inhibitor ( GDC-0941 ) multi-treatments in PTEN-deficient mice lymphoma? Context: To assess the efficacy of multiple treatment of phosphatidylinositol-3-kinase (PI3K) inhibitor on autochthonous tumours in phosphatase and tensin homologue (Pten)-deficient genetically engineered mouse cancer models using a longitudinal magnetic resonance imaging (MRI) protocol. Using 3D MRI, B-cell follicular lymphoma growth was quantified in a Pten(+/-)Lkb1(+/hypo) mouse line, before, during and after repeated treatments with a PI3K inhibitor GDC-0941 (75 mg/kg). Mean pre-treatment linear tumour growth rate was 16.5±12.8 mm(3)/week. Repeated 28-day GDC-0941 administration, with 21 days 'off-treatment', induced average tumour regression of 41±7%. Upon cessation of the second treatment (which was not permanently cytocidal), tumours re-grew with an average linear growth rate of 40.1±15.5 mm(3)/week. There was no evidence of chemoresistance.
assistant
This protocol can accommodate complex dosing schedules, as well as combine different cancer therapies. It reduces biological variability problems and resulted in a 10-fold reduction in mouse numbers compared with terminal assessment methods. It is ideal for preclinical efficacy studies and for phenotyping molecularly characterized mouse models when investigating gene function. Final Decision: yes