Peer-review started: July 5, 2018
First decision: August 2, 2018
Revised: August 4, 2018
Accepted: August 12, 2018
Article in press: August 13, 2018
Published online: September 7, 2018
Processing time: 63 Days and 8.9 Hours
Tumor budding, defined as a small number of cancer cells observed in pathology sections detached from the main tumor mass, is a common phenomenon in cancer. It is suggested that cells in buds are in the process of actively moving away from the primary tumor in the first step of metastasis. Tumor budding has been observed in a variety of carcinomas and is best studied in colorectal cancers where it portends poor prognosis. More recently, tumor budding was found to be of prognostic significance in other cancers including breast cancer. Tumor budding in breast cancer is associated with other adverse pathologic factors, such as larger tumor size and lymphovascular invasion, but may have additional independent prognostic value. In the future, standardization of the quantification criteria for tumor budding may further aid in its adoption as a prognostic marker.
Core tip: Tumor budding, defined as scattered cells or small islands of tumor cells in the vicinity but not connected to the main tumor mass, is a common occurrence in different cancers. In breast cancer, it may portend an adverse prognosis.