Characterization of primary FTSEC in vitro cultures. (a) Primary FTSEC cultures maintain expression of markers expressed by fallopian tube secretory epithelia in vivo (arrowheads indicate secretory, non-ciliated cells), the FTSEC cultures express cytokeratins, CA125, basal laminin, vimentin and nuclear PAX8. 90-100% of cells stain positive for PAX8 suggesting fallopian tube ciliated epithelial cells do not proliferate in vitro. Green stain shows positive staining, nuclei are counterstained with DAPI (blue), except in the case of PAX8. (b) Growth curves. FTSECs have a limited in vitro lifespan, as is typical for primary normal cells. (c) Modal karyotypes for 5/6 primary FTSEC cultures were normal and female (46,XX). # Two cells or fewer showed unbalanced structural chromosomal rearrangements or numerical abnormalities.