PGC and adenocarcinoma: Group 1, consisting of small adenomas with a slightly increased proportion of low-grade cases and no adenocarcinomas, exhibited expression profiles characterised by three overexpressed genes, that is, RACK1, PGC and ACBP. RACK1, previously known as G protein beta-subunit-like protein 12.3, is a signal molecule involved in the MAPK pathway through binding to Src, integrin beta-subunit or interferon receptor (Chang et al, 1998; Liliental and Chang, 1998; Croze et al, 2000; Kiely et al, 2002).