Is entosis seen in vivo?

Yes, entosis has been observed in vivo. In vivo studies have observed entotic cells within tissue samples from breast cancer and in mouse mammary gland tissue. Entotic cells have also been detected in other tissues in the body such as in the liver, skin, and gastrointestinal tract. This suggests that entosis can occur in several different types of tissue. In vitro, entosis was only observed after culturing cells in non adhesive conditions, after starvation, or due to effects of anticancer drugs. In vivo samples of tumors can be found under normal conditions without anticancer treatment, both in primary lesions and metastases. Thus, the cells behave differently.