The role of oncobiosis, characterized by dysregulated microbial ecosystems associated with cancer, has been increasingly acknowledged in promoting the metastasis and dissemination of tumour cells. A comprehensive understanding of the complex interactions between the gut microbiome and metastatic colorectal cancer (mCRC) presents promising avenues for the development of innovative therapeutic approaches centred around modulating the gut microbiome to prevent or hinder metastatic spread. In this comprehensive review, we aim to provide a molecularly focused summary of the implications of the human gut microbiome and microbial metabolites in the initiation and advancement of mCRC. By elucidating these intricate mechanisms, we strive to establish a foundation for future research and the design of novel interventions targeting the gut microbiome to combat this devastating disease.

Cancer metastasis is the primary cause of cancer-related deaths. The seeding of primary tumours at a secondary site is a highly inefficient process requiring substantial alterations in the genetic architecture of cancer cells. These alterations include significant changes in global gene expression patterns. MicroRNAs are small, non-protein coding RNAs which play a central role in regulating gene expression. Here, we focus on microRNA determinants of cancer metastasis and examine microRNA dysregulation in metastatic cancer cells. We dissect the metastatic process in a step-wise manner and summarise the involvement of microRNAs at each step. We also discuss the advantages and limitations of different microRNA-based strategies that have been used to target metastasis in pre-clinical models. Finally, we highlight current clinical trials that use microRNA-based therapies to target advanced or metastatic tumours.

Head and neck squamous cell carcinoma (HNSCC) represents frequent yet aggressive tumours that encompass complex ecosystems of stromal and neoplastic components including a dynamic population of cancer stem cells (CSCs). Recently, research in the field of CSCs has gained increased momentum owing in part to their role in tumourigenicity, metastasis, therapy resistance and relapse. We provide herein a comprehensive assessment of the latest progress in comprehending CSC plasticity, including newly discovered influencing factors and their possible application in HNSCC. We further discuss the dynamic interplay of CSCs within tumour microenvironment considering our evolving appreciation of the contribution of oral microbiota and the pressing need for relevant models depicting their features. In sum, CSCs and tumour plasticity represent an exciting and expanding battleground with great implications for cancer therapy that are only beginning to be appreciated in head and neck oncology.

The interaction between cancer cells and the surrounding microenvironment is determinant for metastasis success. In this study, the ultrastructural relevance of cells in the malignant pleural effusion (MPE) of women with breast cancer history was investigated. In MPE, it is possible to observe single cells and clusters. Women whose MPE presents carcinomas in aggregates have a better prognosis when compared to cases in which metastatic single cells are found. Samples were collected via fine-needle aspiration puncture (US-FNA). Subsequent to the material preparation and ultrathin cuts, they were observed using light and transmission electron microscopy (LM/TEM). LM and TEM images served as a basis for the creation of a digital sculpture using ZBrush® software. Clusters exhibited structural stability, en route vesicles allowing exocytosis of electron-dense fibrous elements, and cytoplasmic protrusions contributing to migratory and invasive skills. Single cells presented different necrotic phenotypes and many displayed leukocyte-like characteristics. Cluster cooperative relationships seem to be related to a long-term permanence in MPE. The absence of a collaborative network presumably triggers a more aggressive behavior of single cells. Its putative fusion with leukocytes can maximize the efficiency for transendothelial migration, increasing chances of metastatic success and, unfortunately, reducing survival of women with recidivism.

An 80-year-old man was seen in urgent neuro-ophthalmology consultation for bilateral vision loss. He had a past medical history of hypertension and metastatic stage IV colorectal adenocarcinoma. Four months prior to presentation, he developed gradual onset, painless blurred vision in his right eye. He underwent cataract surgery in that eye, but his vision continued to decline to the point of no light perception. He developed new onset, painless, blurred vision in his left eye 3 weeks prior to presentation and woke up with no light perception in his left eye one day prior to presentation.