HTR-8/SVneo is a trophoblast cell line that was isolated in 1992 from the placenta of a 6-to-12-week-old embryo. Cells were derived by transfecting the cells that grew out of chorinic villi explants of human first-trimester placenta with the gene encoding for simian virus 40 large T antigen. These cells exhibit a variety of markers characteristic of extravillous invasive trophoblast cells in situ: insulin-like growth factor (IGF)-II, NDOG-5, proliferating cell nuclear antigen (PCNA), human leukocyte antigen framework antigen (W6/32) and a distinct set of integrins including alpha 1, alpha 3, alpha 5, alpha v and beta 1 subunits and alpha v beta 3/beta 5 vitronectin receptor. They were negative formacrophage marker 63/D3, endothelial cell marker factor VIII and alpha 6 and beta 4 integrin subunits. HTR-8/SVneo cells are useful to study trophoblast and placental biology. This cell line was deposited by C Graham (Queen's University).