Dhruvika Varun

Breast cancer (BCa) is one of the most commonly diagnosed malignancies worldwide and is clinically heterogenous. BCa is classified into distinct histopathological and molecular subtypes that inform diagnosis, treatment, and prognosis. Although therapeutic advances, particularly targeted therapies, have improved outcomes, metastatic BCa remains an unmet clinical need. In addition, treatment options remain limited especially for triple negative BCa (TNBC). There is an urgent need to develop novel approaches that can prevent, delay, or reverse disease progression in these patients. The roles of genetic and epigenetic alterations in BCa are well established. Emerging evidence highlights the dysregulation of epitranscriptomic mechanisms involving covalent RNA modifications as a contributing factor in BCa pathogenesis. Notably, recent evidence supports functional crosstalk between epigenetic and epitranscriptomic processes with potential clinical and therapeutic relevance. This review explores key epitranscriptomic RNA modifications, m⁶A, m⁶A_m, m⁵C, m⁷G, and m¹A in the context of BCa. The functional consequences of the epitranscriptomic regulators ("writers," "erasers", and "readers") are discussed alongside the accumulating evidence of their contribution to cancer development and progression. This review considers how RNA modifications and their regulators might serve as biomarkers or therapeutic targets and offers new directions for translational research and clinical intervention in BCa.

In hormone-dependent cancers, front-line treatment options include surgery and therapies that target hormone dependance. These therapies are effective initially but fail in tumors that recur, develop resistance or present at an advanced stage. Consequently, new therapeutic avenues are urgently needed. Increasing evidence implicates epigenetic modulators in tumor initiation, progression and therapeutic response, making them attractive biomarkers for patient stratification and targets for intervention. Over the past two decades, the discovery and development of small-molecule inhibitors directed against key epigenetic regulators have accelerated. This review provides a comprehensive overview of the major epigenetic targets, the inhibitors developed against them and the clinical trials currently underway in endocrine-related cancers. While epigenetic agents have shown limited benefits as monotherapies, their use in combination regimens is emerging as a strategy to overcome resistance and enhance the efficacy of existing treatments. We summarize the current landscape of combination trials, highlight early signs of clinical activity and discuss the opportunities and challenges inherent in integrating epigenetic drugs into the management of advanced endocrine-related cancers.

Osteosarcoma (OSA) is the most prevalent bone malignancy in people and dogs. Current survival rates show the need for advances in novel therapies to help overcome the growth, survival and metastatic progression of the cancer. Canine models are often used to advance prognostic and treatment opportunities for OSA due to the similarities in the disease between species. This study focusses on the genetic and molecular similarities of OSA between human and canine specimens. Differentially expressed genes (DEGs) were compared and identified in canine and human OSA tumours, revealing 86 common genes, 36 having high and 50 having low expression. Further immunohistochemical analysis of the corresponding proteins of three identified DEGs (ASPN, STK3, BAMBI) allowed for the visualisation of protein expression in canine OSA tissues (n = 19). Overall nuclear and cytoplasmic H-scores were generated, and nuclear and cytoplasmic scores in males and females and in different anatomical locations (axial versus appendicular) were also investigated, presenting unique opportunities to understand the expression in this cancer type. This study contributes to a deeper knowledge of genetic pathways changes and identifies avenues for the diagnosis, prognosis and treatment of OSA in people and dogs, whilst encompassing the One Health concept in medicine.

Osteosarcoma (OSA) is the most common type of primary bone malignancy in people and dogs. Our previous molecular comparisons of canine OSA against healthy bone resulted in the identification of differentially expressed protein-expressing genes (forkhead box protein O4 (FOXO4), interferon regulatory factor 8 (IRF8), and lymphoid enhancer binding factor 1 (LEF1)). Immunohistochemistry (IHC) and H-scoring provided semi-quantitative assessment of nuclear and cytoplasmic staining alongside qualitative data to contextualise staining (n = 26 patients). FOXO4 was expressed predominantly in the cytoplasm with significantly lower nuclear H-scores. IRF8 H-scores ranged from 0 to 3 throughout the cohort in the nucleus and cytoplasm. LEF1 was expressed in all patients with significantly lower cytoplasmic staining compared to nuclear. No sex or anatomical location differences were observed. While reduced levels of FOXO4 might indicate malignancy, the weak or absent protein expression limits its primary use as diagnostic tumour marker. IRF8 and LEF1 have more potential for prognostic and diagnostic uses and facilitate further understanding of their roles within their respective molecular pathways, including Wnt/beta-catenin/LEF1 signalling and differential regulation of tumour suppressor genes. Deeper understanding of the mechanisms involved in OSA are essential contributions towards the development of novel diagnostic, prognostic, and treatment options in human and veterinary medicine contexts.