By using tissue microarrays and immunohisto-chemical analysis, we studied protein expression of genes in the erb-b signaling pathway (erb-b1; erb-b2; phosphoinositide-3-kinase, catalytic, a polypeptide [PIK3CA]; phosphatase and tensin homologue [PTEN]; phosphorylated AKT [p-AKT]; and phosphorylated extracellular signal-regulated kinase [p-ERK]) in 118 advanced ovarian carcinomas and related expression to clinicopathologic features and survival. High protein expression was seen in 15.3% of cases for erb-b2, 44.1% for erb-b1, 43.2% for PIK3CA, 51.6% for p-AKT, and 28.0% for p-ERK. Low protein levels of PTEN were seen in 41.5% of the cases and tended to be more common in well-differentiated tumors. In multivariate analysis, only high expression of both erb-b1 and erb-b2 was an independent factor in progression-free and disease-specific survival (P=.009, hazard ratio=2.46; P=.002, hazard ratio=3.023, respectively). The PI3K/AKT and RAS/MEK/ERK pathways seem to be activated in some cases of advanced ovarian carcinomas, although PIK3CA, p-AKT, p-ERK, and PTEN do not seem to be independent prognostic markers in this group of patients.