Cancers

Background: Despite the emergence of new treatment modalities, including targeted therapies that are of benefit to patients whose tumours carry specific mutations, the prognosis for most patients with cholangiocarcinoma remains poor. Novel therapeutic approaches that can benefit the majority of patients whose tumour cells do not carry targetable mutations are urgently needed. Results: To identify mutation-agnostic treatment approaches, we screened a library of well-tolerated off-patent drugs against cholangiocarcinoma cells and normal biliary epithelial cells. The screen identified Niclosamide as a drug that reduces the viability of multiple cholangiocarcinoma cell lines but has a lesser effect on normal primary biliary epithelial cells. Moreover, Niclosamide treatment reduces the growth of cholangiocarcinoma tumour cells as tumour spheroids in vitro and reduces the growth of cholangiocarcinoma cells as tumours in a xenograft mouse model of this disease. Through a proteasome-dependent mechanism, Niclosamide treatment reduces the expression of the Proline-Rich Homeodomain (PRH) protein, a transcription factor which acts as an oncoprotein in cholangiocarcinoma cells. However, PRH knockout does not alter the sensitivity of cholangiocarcinoma cells to Niclosamide, indicating that this drug is not dependent on PRH to reduce cell viability. Interestingly, the CDK4/6 kinase inhibitor Palbociclib selectively reduces the viability of cholangiocarcinoma cell lines compared to normal biliary epithelial cells and, importantly, Palbociclib synergises with Niclosamide to reduce cholangiocarcinoma cell viability in vitro as well as to reduce tumour growth in a mouse xenograft model. Conclusion: These preclinical results suggest that the combination of Niclosamide and an inhibitor of CDK4/6 is worthy of clinical evaluation as a potential treatment for this disease.

Studies of the genomic stability of Ewing sarcoma (EwS) have produced contradictory findings. While they are generally characterized by low mutation rates of individual genes, several cases exhibit genomic alterations that manifest as chromosomal gains and losses. Taken together, these alterations represent independent biomarkers for EwS, such as loss of heterozygosity (LOH) or an altered genome. Patients with primary EwS tumors with fewer than three copy number alterations (CNAs) have a better prognosis than those with more CNAs. The functional mechanisms underlying this chromosomal instability are not yet clear. However, there are indications that this may be directly caused by the EWSR1::ETS translocations that are characteristic of EwS. The transcriptional behavior of the chimeric transcription factor EWSR1-FLI1 leads to the formation of R-loop DNA–RNA hybrids that form when RNA binds back to DNA during transcription and increased replication stress, which may result in structural chromosomal changes. Additionally, the formation of EWSR1 fusion genes in EwS results in the loss of one or both wild-type EWSR1 alleles in sarcoma cells. As chromosome segregation has been observed under loss of wild-type EWSR1, EWSR1 loss has been proposed as a potential source of LOH. So, it is highly probable that a chromosomal translocation and the subsequent formation of the EWSR1-ETS fusion protein cause the genomic alterations in EwS. This indicates that targeted therapy should be directed against the CNA and LOH biology caused by the fusion protein.

Biomarkers have transformed cancer care by linking molecular insights to personalized treatment strategies. This review first surveys the spectrum of detection modalities, including tissue genomics and histopathology; liquid biopsies such as circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and extracellular vesicles; imaging and radiomics; and multi-omic approaches spanning epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We then critically appraise the translational challenges that hinder clinical implementation, assay standardization, data integration, analytical and clinical validation, regulatory pathways, and cost-effectiveness. Finally, we explore emerging solutions, including artificial intelligence (AI)-driven multi-modal phenotyping, adaptive trial designs, and point-of-care assays, and outline future directions for expanding access and equitable adoption. By emphasizing the central role of biomarkers in guiding targeted and immune-based therapies, we underscore their potential to overcome tumor heterogeneity, preempt resistance, and ultimately improve patient outcomes.