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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2006.12.007 Byline: Carla P. Martins (1), Lamorna Brown-Swigart (1), Gerard I. Evan (1) Abstract: Although restoration of p53 function is an attractive tumor-specific therapeutic strategy, it remains unclear whether p53 loss is required only for transition through early bottlenecks in tumorigenesis or also for maintenance of established tumors. To explore the efficacy of p53 reinstatement as a tumor therapy, we used a reversibly switchable p53 knockin (KI) mouse model that permits modulation of p53 status from wild-type to knockout, at will. Using the well-characterized E[mu]-myc lymphoma model, we show that p53 is spontaneously activated when restored in established E[mu]-myc lymphomas in vivo, triggering rapid apoptosis and conferring a significant increase in survival. Nonetheless, reimposition of p53 function potently selects for emergence of p53-resistant tumors through inactivation of p19.sup.ARF or p53. Our study provides important insights into the nature and timing of p53-activating signals in established tumors and how resistance to p53 evolves, which will aid in the optimization of p53-based tumor therapies. Author Affiliation: (1) Cancer Research Institute and Department of Cellular and Molecular Pharmacology, Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA Article History: Received 26 July 2006; Revised 9 November 2006; Accepted 8 December 2006 Article Note: (miscellaneous) Published online: December 21, 2006

A reversibly switchable mouse transgenic model of Myc-dependent Beta-cell carcinogenesis is used to delineate the kinetics and causal sequence of angingenic processes following acute Myc activation. It is shown that the onset of endothelial cell proliferation is induced shortly after Myc-induced cell cycle entry of beta cells.

Only a subset of patients with breast cancer responds to immune checkpoint blockade (ICB). To better understand the underlying mechanisms, we analyze pretreatment biopsies from patients in the I-SPY 2 trial who receive neoadjuvant ICB using multiple platforms to profile the tumor microenvironment. A variety of immune cell populations and markers of immune/cytokine signaling associate with pathologic complete response (pCR). Interestingly, these differ by breast cancer receptor subtype. Measures of the spatial distributions of immune cells within the tumor microenvironment, in particular colocalization or close spatial proximity of PD-1 + T cells with PD-L1 + cells (immune and tumor cells), are significantly associated with response in the overall cohort as well as the in the triple negative (TN) and HR + HER2 - subtypes. Our findings indicate that biomarkers associated with immune cell signaling, immune cell densities, and spatial metrics are predictive of neoadjuvant ICB efficacy in breast cancer., Competing Interests: Declaration of interests J.W. reports honoraria from DAVA Oncology; consults for Baylor College of Medicine; has ownership in Theralink; and is co-inventor of the RPPA technology, and phospho-HER2 and -EGFR response predictors with filed patents. C.H. is an employee of Akoya Biosciences. R.N. reports grants from Quantum Leap, AstraZeneca, Celgene, Corcept Therapeutics, Genentech/Roche, Immunomedics, Merck, OBI Pharma, Odonate Therapeutics, Pfizer, and Seattle Genetics outside the submitted work; and personal fees from Aduro, AstraZeneca, Athenex, Celgene, Daiichi Sankyo, G1 Therapeutics, Genentech, MacroGenics, Merck, Novartis, Pfizer, Puma, and Syndax. M.C.L. reports support from Eisai, Genentech, GRAIL, Menarini Silicon Biosystems, Merck, Novartis, Seattle Genetics, and Tesaro. D.Y. reports unrelated support from Boehringer Ingelheim. A.M.D. reports honoraria or consulting for Pfizer and Context Therapeutics and reports support from Novartis, Pfizer, Genentech, Calithera, and Menarini. L.P. reports consulting fees and honoraria for advisory board participation from Pfizer, AstraZeneca, Merck, Novartis, Bristol-Myers Squibb, GlaxoSmithKline, Genentech/Roche, Personalis, Daiichi, Natera, and Exact Sciences and institutional research funding from Seagen, GlaxoSmithKline, AstraZeneca, Merck, Pfizer, and Bristol-Myers Squibb. D.A.B. is co-owner of Berry Consultants LLC, a company that designs adaptive clinical trials (including I-SPY2). E.F.P. reports leadership, stock/ownership, consulting/advisory, and travel funds from Perthera and Ceres Nanosciences; stock and consulting/advisory for Theralink Technologies, Inc; support from Ceres Nanosciences, GlaxoSmithKline, AbbVie, Symphogen, Genentech, SpringWorks Therapeutics, and Deciphera Therapeutics; and patents/royalties from NIH and filed patents for p-HER2 and p-EGFR response predictors. L.v.V. is a co-inventor of the MammaPrint signature and a part-time employee and stockholder of Agendia NV. L.E. is an unpaid member of the board of directors of Quantum Leap Healthcare Collaborative (QLHC), has received grant support from QLHC for the I-SPY2 trial, and is on the Blue Cross/Blue Shield Medical Advisory Panel., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

HER2-targeted therapy dramatically improves outcomes in early breast cancer. Here we report the results of two HER2-targeted combinations in the neoadjuvant I-SPY2 phase 2 adaptive platform trial for early breast cancer at high risk of recurrence: ado-trastuzumab emtansine plus pertuzumab (T-DM1/P) and paclitaxel, trastuzumab and pertuzumab (THP). Eligible women have >2.5 cm clinical stage II/III HER2 + breast cancer, adaptively randomized to T-DM1/P, THP, or a common control arm of paclitaxel/trastuzumab (TH), followed by doxorubicin/cyclophosphamide, then surgery. Both T-DM1/P and THP arms 'graduate' in all subtypes: predicted pCR rates are 63%, 72% and 33% for T-DM1/P (n = 52), THP (n = 45) and TH (n = 31) respectively. Toxicity burden is similar between arms. Degree of HER2 pathway signaling and phosphorylation in pretreatment biopsy specimens are associated with response to both T-DM1/P and THP and can further identify highly responsive HER2 + tumors to HER2-directed therapy. This may help identify patients who can safely de-escalate cytotoxic chemotherapy without compromising excellent outcome., (© 2021. The Author(s).)