Upregulation of gene expression in ex vivo–isolated liver endothelial cells from tumor-bearing immuno-incompetent mice. ESbL-lacZ lymphoma cells were injected intradermally into BALB/c (nu/nu) mice. Seven days later, endothelial cells were isolated from control (C) and tumor-bearing mice (day 7) and analyzed as described in the legend to Fig 3 and in Materials and Methods. The pBluescript SK DNA (vector), which was used as a control, gave no nonspecific background signals. The difference in the expression of all four genes between C and the day 7 tumor-bearing immuno-incompetent host was significant (P = .003, paired t-test).