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Simple Summary: This study investigates the fecal and tumor microbiome as potential biomarkers of tumor response to neoadjuvant immunotherapy in combination with chemoradiation. We performed 16S rRNA amplicon sequencing on fecal and tumor samples, as well as fecal metabolomics, on biosamples collected from patients with resectable esophageal or gastroesophageal junction carcinoma before and during treatment. The fecal microbiome of patients whose tumors achieved a pathologic complete response revealed enrichment in sphingolipid and primary bile acids, with corresponding elevated abundance of several bacterial species: Roseburis inulinivorans, Ruminococcus callidus, and Fusicantenibacter saccharivorans. While these results provide initial insight, further study is necessary to validate these data and determine how microbes alter the immune response with neoadjuvant immunotherapy. Background: Preclinical and clinical data indicate that chemoradiotherapy (CRT) in combination with checkpoint inhibitors may prime an anti-tumor immunological response in esophageal cancer. However, responses to neoadjuvant therapy can vary widely and the key biomarkers to determine response remain poorly understood. The fecal microbiome is a novel and potentially modifiable biomarker of immunotherapy response, and both fecal and tumor microbes have been found to associate with outcomes in esophageal cancer. Methods: Fecal and tumor samples were collected from patients with stage II–III resectable esophageal or gastroesophageal junction carcinoma treated with neoadjuvant immune checkpoint inhibitors (ICIs) plus CRT prior to surgical resection. Microbiome profiles were analyzed by 16S rRNA amplicon sequencing and taxonomic data were integrated with fecal metabolite analysis to assess microbial function. Results: The fecal microbiome of patients with pathological complete response (PCR) grouped in distinct clusters compared to patients with residual viable tumor (RVT) by Bray–Curtis diversity metric. Integrated taxonomic and metabolomic analysis of fecal samples identified a sphingolipid and primary bile acid as enriched in the PCR, the levels of which correlated with several bacterial species: Roseburis inulinivorans, Ruminococcus callidus, and Fusicantenibacter saccharivorans. Analysis of the tumor microbiome profiles identified several bacterial genera previously associated with esophageal tumors, including Streptococcus and Veillonella. Conclusions: These results further characterize the fecal and tumor microbiome of patients with operable esophageal cancer and identify specific microbes and metabolites that may help elucidate how microbes contribute to tumor response with neoadjuvant CRT combined with ICI. [ABSTRACT FROM AUTHOR]

Immunotherapy holds potential as a treatment for gastric cancer (GC), though immune checkpoint inhibitor (ICI) resistance remains an obstacle. One resistance mechanism involves defects in interferon-γ (IFN-γ) signaling, in which IFN-γ is linked to improved responsiveness to ICIs. Herein, the roles of RNA N 6 -methyladenosine (m6A) modifications in regulation of IFN-γ signaling and the responsiveness to ICIs are unveiled. The m6A-binding protein YTH N 6 -methyladenosine RNA-binding protein F1 (YTHDF1) is overexpressed in GC tissues, correlating with the suppression of cancer immunity and poorer survival rates. YTHDF1 overexpression impaired the responsiveness to IFN-γ in GC cells, and knockdown studies indicated the redundant effects of YTHDF2 and YTHDF3 with YTHDF1 in IFN-γ responsiveness. RNA immunoprecipitation sequencing revealed YTHDFs directly target interferon regulatory factor 1 (IRF1) mRNA, a master regulator of IFN-γ signaling, leading to reduced RNA stability and consequent downregulation of IFN-γ signaling. Furthermore, in mouse syngeneic tumor models, Ythdf1 depletion in cancer cells resulted in reduced tumor growth and increased tumor-infiltrating lymphocytes, which are attributed to the augmentation of IFN-γ signaling. Collectively, these findings highlight how YTHDFs modulate cancer immunity by influencing IFN-γ signaling through IRF1 regulation, suggesting their viability as therapeutic targets in cancer immunotherapy., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Background: Fibromatosis of the breast, also known as desmoid-type fibromatosis (DTF), is a rare tumor marked by the development of non-metastatic, locally aggressive tumors in breast tissue. It represents only 0.2% of all breast tumors. It is a nonmalignant tumor that often resembles cancer in both its clinical presentation and radiologic imaging characteristics, posing unique diagnostic and management challenges., Case Description: This is a case report of a 34-year-old female with a history of bilateral silicone implant placement who presented with bilateral breast masses. She reported a 6-month history of a 1-cm firm, palpable mass in the right breast without associated pain or growth. She had a family history of breast, pancreatic, and prostate cancer but no significant past medical history. Ultrasound-guided biopsy of the right breast and magnetic resonance imaging (MRI)-guided biopsy of the left breast both revealed fibromatoses. She underwent bilateral excisional biopsies and surgical pathology confirmed breast fibromatosis in the background of benign breast tissue with fibrocystic changes. The patient had an uncomplicated post-operative course., Conclusions: This case report of a patient with prior breast augmentation surgery highlights the clinical presentation, diagnosis, and management of breast fibromatosis. The intricate relationship between desmoid tumors and factors such as tissue injury, surgical trauma, exogenous hormone exposure, and genetics is discussed. Ultimately, comprehensive diagnostic and therapeutic approaches with individualized treatment strategies are essential for managing fibromatosis effectively., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-24-84/coif). E.O. received research funding from the Bristol Myers Squibb foundation for unrelated research work. The other authors have no conflicts of interest to declare., (2025 AME Publishing Company. All rights reserved.)