HER2 mutation as an emerging target in advanced breast cancer.

HER2 activating mutations have emerged as oncogenic drivers and therapeutic targets in a variety of human tumors. In breast cancer, these deregulations occur at low frequency, and are mostly detected in HER2-nonamplified, metastatic disease. Preclinical evidence has clarified the role of hotspot mutations in HER2 constitutive activation, defining them as an alternative mechanism to HER2 gene amplification. Furthermore, recent clinical studies have indicated the emergence of newly acquired HER2 deregulations in significant proportions of breast cancer patients who experience disease progression following both endocrine and HER2-targeted therapies. As the involvement of HER2 mutation in therapy resistance may profoundly impact patient outcomes on successive therapies, several clinical trials are currently investigating the efficacy of various HER2-targeted drugs in HER2-mutant breast cancer. In this review, we firstly summarize the structural organization of the HER2 oncogene and its historical impact on breast cancer prognosis and therapeutic advancement. Then, we provide an overview of the frequencies and functional relevance of clinically recurrent HER2 mutations in breast cancer with a special focus on their role in therapeutic resistance. Finally, we provide a collection of the clinical trials that are currently exploring novel therapeutic approaches for this patient subset and discuss the related perspectives and challenges.

Role of Hippo pathway dysregulation from gastrointestinal premalignant lesions to cancer.

BACKGROUND: First identified in Drosophila melanogaster, the Hippo pathway is considered a major regulatory cascade controlling tissue homeostasis and organ development. Hippo signaling components include kinases whose activity regulates YAP and TAZ final effectors. In response to upstream stimuli, YAP and TAZ control transcriptional programs involved in cell proliferation, cytoskeletal reorganization and stemness. MAIN TEXT: While fine tuning of Hippo cascade components is essential for maintaining the balance between proliferative and non-proliferative signals, pathway signaling is frequently dysregulated in gastrointestinal cancers. Also, YAP/TAZ aberrant activation has been described in conditions characterized by chronic inflammation that precede cancer development, suggesting a role of Hippo effectors in triggering carcinogenesis. In this review, we summarize the architecture of the Hippo pathway and discuss the involvement of signaling cascade unbalances in premalignant lesions of the gastrointestinal tract, providing a focus on the underlying molecular mechanisms. CONCLUSIONS: The biology of premalignant Hippo signaling dysregulation needs further investigation in order to elucidate the evolutionary trajectories triggering cancer inititation and develop effective early therapeutic strategies targeting the Hippo/YAP pathway.

Transcriptional Phenocopies of Deleterious KEAP1 Mutations Correlate with Survival Outcomes in Lung Cancer Treated with Immunotherapy.

PURPOSE: Co-occurring mutations in KEAP1 and STK11/KRAS have emerged as determinants of survival outcomes in patients with non-small cell lung cancer (NSCLC) treated with immunotherapy. However, these mutational contexts identify a fraction of nonresponders to immune checkpoint inhibitors. We hypothesized that KEAP1 wild-type tumors recapitulate the transcriptional footprint of KEAP1 mutations and that this KEAPness phenotype can determine immune responsiveness with higher precision compared to mutation-based models. EXPERIMENTAL DESIGN: The Cancer Genome Atlas was used to infer the KEAPness phenotype and explore its immunological correlates at the pan-cancer level. The association between KEAPness and survival outcomes was tested in two independent cohorts of patients with advanced NSCLC treated with immunotherapy and profiled by RNA sequencing (SU2C n = 153; OAK/POPLAR n = 439). The NSCLC TRACERx421 multiregion sequencing study (tumor regions, n = 947) was used to investigate evolutionary trajectories. RESULTS: KEAPness-dominant tumors represented 50% of all NSCLCs and were associated with shorter progression-free survival (PFS) and overall survival (OS) compared to KEAPness-free cases in independent cohorts of patients with NSCLC treated with immunotherapy (SU2C PFS P = 0.042, OS P = 0.008; OAK/POPLAR PFS P = 0.0014, OS P < 0.001). Patients with KEAPness tumors had survival outcomes comparable to those with KEAP1-mutant tumors. In the TRACERx421, KEAPness exhibited limited transcriptional intratumoral heterogeneity and immune exclusion, resembling the KEAP1-mutant disease. This phenotypic state occurred across genetically divergent tumors, exhibiting shared and private cancer genes under positive selection when compared to KEAP1-mutant tumors. CONCLUSIONS: We identified a KEAPness phenotype across evolutionary divergent tumors. KEAPness outperforms mutation-based classifiers as a biomarker of inferior survival outcomes in patients with NSCLC treated with immunotherapy.

Evaluation of Horses' Daytime Activity Budget in a Model of Ethological Stable: A Case Study in Italy.

The increasing interest in animal welfare and the knowledge of equine physiological and ethological needs have led to the development of different types of horses' management and housing systems. The research presented here aimed to assess the daytime activity budget of horses. Focal animal sampling was used as an observational sampling method, and the five animals were observed for a total of 9920 minutes in the paddock and inside the stall. The results showed that horses spent most of the daytime in foraging behaviors, followed by resting behaviors, and locomotion. Social behaviors (s.e. allogrooming, olfactory investigation) were rare, and the stereotypic behaviors (s.e. oral and locomotor stereotypies) occupied 2.74%±2.74% of the total time. The percentage of time spent in foraging, resting, and locomotion, reflects the activity budget observed in free-roaming feral horses. However, the rare occurrence of positive social interactions and the presence of some stereotypies could be aspects to ameliorate. This kind of housing facility could be considered a good alternative to traditional management; indeed, it might offer a better trade-off between the needs of the horse and the management goals from humans.