Adenocarcinomas and their derived lymphovascular emboli contain dual compartmental populations of tumor microvesicles which differ in size and possibly content and function.

Adenocarcinomas and their associated lymphovascular emboli metastasize as tight aggregates of tumor cells. Using a xenograft model of human inflammatory breast cancer (Mary-X), which exhibited florid lymphovascular emboli in mice and high density tumor aggregates (spheroids) in vitro, we previously demonstrated that both emboli and spheroids are mediated by an intact overexpressed E-cadherin axis which regulates homotypic tumor cell adhesion. We now report that Mary-X spheroids secrete 5-10 fold higher levels of microvesicles (MVs) than most other carcinoma cell lines. Despite the high density of tumor cells and the strong juxtaposition of tumor cells to each other in the spheroids, interce…