cDNA-based Transcript Analysis of Autologous Eutopic and Ectopic Endometrium of Women with Moderate and Severe Endometriosis

Purpose To explore differential gene expression between autologous eutopic and ectopic endometrium and the effect of phases, infertility, and severity of disease on this. Methods cDNA arrays followed by post hoc analysis for 1190 selected human genes were performed to analyze transcript expression in autologous eutopic and ectopic endometrial samples obtained from 6 proven fertile and 4 subfertile volunteers with endometriosis (stage 3: n=5; stage 4: n=5) during either the proliferative (n=7) or secretory (n=3) phase. Results cDNA-based expression array analysis appeared sensitive, precise, and reliable in unsupervised analysis and quantitative RT-PCR. Sample clustering analysis revealed maximal cluster coefficient (C=0.8) between eutopic and ectopic clusters for all pairs, followed by that yielded by phases of cycle (C=0.6); fertility history (C=0.3), and stages of severity (C=0.3) had marginal effects. Of 42 genes showing differential regulation in pooled analysis, 3 genes (CAGA, MT2A, and VIM) were up-regulated and 39 genes including EPHA2, FOXM1, HPSE, ITGA5, ITGAE, ITGB3, PAEP, and TGFBR1 were down-regulated in ectopic endometrium. The high transcript number of AFP, ALOX15, F2RL1, and PRKCG in proliferative phase eutopic endometrium appears to be a potential biomarker for endometriosis. Conclusions Differential expression of specific genes appeared as distinguishing features for ectopic endometrium compared with eutopic endometrium; many of them might be associated with poor cellular integrity of endometriotic cells. However, ectopic endometrium did not show overt molecular indication of tumorigenic potential.