Gene microarray technology is highly effective in screening for differential gene expression and has hence become a popular tool in the molecular investigation of cancer. In the present study, cDNA microarrays containing 2,000 different genes were used to analyze gene expression profiles in ten human postmenopausal endometrioid-paired carcinoma specimens versus corresponding adjacent normal tissue to identify differentially expressed genes. In our study several genes were found differentially expressed. One of them was the MAP3K8, a gene that has never been described to be overexpressed in this kind of malignancy. To validate the differential expression of this gene as well as the membrane array, we performed semiquantitative reverse transcription-PCR analysis. MAP3K8 was found overexpressed in 30% of the endometrial carcinoma samples. To the best of our knowledge this is the first report showing the MAP3K8 oncogene linked to human endometrial carcinoma suggesting that it may be another molecule involved in human endometrial cancer.