Effect of IGFBP-5 expression on PaC cells grown in the absence of serum. Stable transfectants (empty vector/Vec-white bar, low/IGFBP-5L-gray bar, high/IGFBP-5H-black bar) were seeded in growth media for 24 h then switched to serum-free medium (SFM) for the remainder of the growth period. Cell counts (A) or thymidine incorporation (B) were determined at 72, 96 and 120 h post-seeding. Data shown represent the mean ± SE of IGFBP-5-transfected cell growth relative to vector-transfected controls (100%) from 3-5 separate experiments performed in duplicate. aP < 0.05, bP < 0.01, dP < 0.001.