Endothelial-to-mesenchymal transition (EndMT) is a dynamic cellular process characterized by a phenotypic-functional switch of cells from endothelial-to-mesenchymal traits. Many studies have identified EndMT as a key driver of tumor growth and progression. EndMT supports tumor cell proliferation by creating a tumor microenvironment that facilitates cancer cell survival. Notably, EndMT is an important source of cancer-associated fibroblasts, leads to immune dysregulation and immune escape, and supports metastasis and resistance to therapy. Hence, understanding the intricate relationship between EndMT and cancer progression offers exciting new avenues for therapeutic intervention. This review aims to describe the central role of EndMT in tumor progression, highlighting the molecular mechanisms underlying this endothelial alteration and its significant involvement at all stages of tumor progression.

Genomic-oriented oncology has improved tumor classification, treatment options, and patient outcomes. However, genetic heterogeneity, tumor cell plasticity, and the ability of cancer cells to hijack the tumor microenvironment (TME) represent a major roadblock for cancer eradication. Recent biotechnological advances in organotypic cell cultures have revolutionized biomedical research, opening new avenues to explore the use of cancer organoids in functional precision oncology, especially when genomics alone is not a determinant. Here, we outline the potential and the limitations of tumor organoids in preclinical and translational studies with a particular focus on lung cancer pathogenesis, highlighting their relevance in predicting therapy response, evaluating treatment toxicity, and designing novel anticancer strategies. Furthermore, we describe innovative organotypic coculture systems to dissect the crosstalk with the TME and to test the efficacy of different immunotherapy approaches, including adoptive cell therapy. Finally, we discuss the potential clinical relevance of microfluidic mini-organ technology, capable of reproducing tumor vasculature and the dynamics of tumor initiation and progression, as well as immunomodulatory interactions among tumor organoids, cancer-associated fibroblasts (CAFs) and immune cells, paving the way for next-generation immune precision oncology.