Expression of GATA-6 in neoplastic human adrenal tissues was evaluated by RT-PCR and dot-blot hybridization. RT-PCR products were resolved in 2% agarose gels. Tissue samples represented here, as well as in Figures 3–5, correspond to patients listed in Table 1. Samples 22a and 22b are tumor specimens removed from left (22a) and right (22b) adrenal of the same patient (patient 22, Table 1). M: 1 kb molecular size ladder Ad: normal adrenal. +: genomic DNA. -: negative control for RT-PCR. Samples 1 to 13: non-metastasizing; samples 14 to 22: metastasizing/recurring adrenocortical tumors.