Narrative review: research progress of tumor budding in gastrointestinal tumor

Abstract

: Tumor budding is a histological phenomenon observed in various cancers, which means that single malignant cells and/or small malignant cell clusters can be observed in the tumor stroma. In several retrospective studies, it has been found that tumor budding is related to the poor prognosis of tumors. Tumor budding has been included in the guidelines for the treatment of colorectal cancer in 2017. However, significant heterogeneity in its accurate definition, evaluation methods, and patient stratification need to be addressed. The mechanism of tumor budding remains unclear. Tumor budding was considered to be the manifestation of tumor epithelial-mesenchymal transition (EMT) in the early stage, but it was considered to be the manifestation of “partial EMT” in recent years. Some researchers have tried to explain budding by molecular pathways, however, it is still not clear the important genetic mutations in tumor budding as so far. In colorectal cancer, tumor budding provides an important guide for tumor staging and treatment in clinical practice. For other gastrointestinal tumor except colorectal cancer, there have been some studies on the tumor budding, but further research is needed to evaluate its significance. This review aims to summarize the history, current status, controversy, and the latest research in gastrointestinal tumors of tumor budding.