Colorectal cancer (CRC) is the third leading cause of cancer-related death in the United States. Emerging evidence highlights the significant role of gut microbiota dysbiosis, characterized by a reduction in beneficial bacteria and an increase in pro-inflammatory and pro-carcinogenic bacteria, in CRC pathogenesis. Both genetic and environmental factors, including diet, antibiotic use, physical activity, aging, and obesity, contribute to this microbial imbalance. Dysbiosis promotes chronic inflammation and immune dysregulation, which facilitates tumor initiation and progression. This review examines the intricate interactions between gut microbiota, immune modulation, and CRC development. It explores current and emerging therapeutic strategies that target the microbiome to enhance treatment efficacy, discusses interventions aimed at restoring healthy microbiota in CRC patients, and outlines future directions for microbiome-based therapies to improve clinical outcomes.

Biliary tract cancers (BTCs) are aggressive malignancies associated with poor prognosis and limited treatment options. Advances in precision oncology, notably the identification of recurrent molecular alterations such as fibroblast growth factor receptor 2 (FGFR2) fusions, isocitrate dehydrogenase 1 (IDH1) mutations, ERBB2 amplifications, and v-Raf murine sarcoma viral oncogene homolog B (BRAF) V600E mutations, have introduced new therapeutic avenues and modest survival benefits for patients with advanced disease. However, the practical implementation of targeted therapies remains hampered by challenges in tumor tissue acquisition and molecular testing, highlighting the need for alternative genomic profiling strategies. This comprehensive review examines the role of liquid biopsy as a non-invasive strategy for molecular profiling in BTCs, with a focus on the clinical applications of plasma and bile-derived circulating tumor DNA (ctDNA). We synthesized findings from recent clinical studies evaluating mutation detection rates, concordance between liquid biopsy and tissue-based assays, and the comparative performance of plasma versus bile ctDNA. Liquid biopsy demonstrates high rates of mutation detection and good concordance with tissue analyses. Bile-derived ctDNA, owing to its proximity to the tumor, consistently shows higher sensitivity and mutant allele frequencies (MAFs) than plasma ctDNA. Nevertheless, challenges remain, including lower sensitivity for detecting structural alterations (e.g., gene fusions), variability in ctDNA yield depending on disease status, and a lack of assay standardization across platforms. Liquid biopsy, particularly through bile ctDNA analysis, emerges as a promising adjunct to tissue biopsy for molecular profiling in BTCs. It offers opportunities for earlier, less invasive, and more personalized treatment decisions. Future directions should aim at developing tumor-informed liquid biopsy strategies that increase precision, reduce costs, and ultimately improve patient outcomes. Prospective studies are needed to confirm its clinical utility and survival impact.

Fibroblast growth factor receptor 1 (FGFR1) plays a critical role in the progression of various cancers through its involvement in cell proliferation, survival, and differentiation. More recently, FGFR1 has been implicated in the mechanisms of immune evasion, particularly its role in resistance to immune checkpoint inhibitors (ICIs) such as pembrolizumab and nivolumab. Targeting FGFR1 with monoclonal antibodies and tyrosine kinase inhibitors has emerged as a promising therapeutic strategy to enhance ICI efficacy by altering the tumor microenvironment and countering immune suppression. Preclinical studies demonstrate that combining FGFR1 inhibitors, such as the novel monoclonal antibody OM-RCA-01, with ICIs significantly improves antitumor activity, enhancing T cell responses and cytokine production. This article explores the role of FGFR1 in cancer biology, its contribution to immunotherapy resistance, and the therapeutic potential of targeting FGFR1 to enhance the efficacy of ICIs.