Evolution tumour models paving the way for understanding oral carcinogenesis

Throughout the centuries, the world's outstanding scientists and research groups have gathered their efforts to characterise the initiation and progression of malignant neoplasms. The temporal dissection of tumourigenesis provided by phylogenetic studies is one of the milestones in understanding cancer; however, some black boxes are still unsolved. Currently, there is no consensus regarding the development of oral squamous cell carcinoma (OSCC), the leading cancer of the head and neck region. Oral epithelial dysplasia (OED) may precede oral cancer and, occasionally, be clinically evident as white, red or mixed mucosal lesions, called oral potentially malignant disorders (OPMD). In a stepwise view of oral carcinogenesis, OED and OPMD have been considered harbingers of oral cancer. Nevertheless, the malignant transformation of OPMD is a rare event. Most of these disorders remain benign and can even regress, making it challenging to formulate evolutionary hypotheses for OSCC initiation. Deciphering OED evolution is vital to highlight the potential drivers of oral carcinogenesis and molecular targets for OSCC preventative and therapeutic strategies. This narrative review synthesises the main concepts of evolutionary theories and discusses which of them better explains OED development and malignant transformation.