We then analyzed gene expression from endometriosis I/II and III/IV samples in the proliferative phase, focusing on genes in the top five significantly enriched KEGG pathways: (1) ECM-receptor interaction, (2) cytokine–cytokine receptor interaction, (3) PI3K-Akt signaling pathway, (4) focal adhesion, and (5) protein digestion and absorption. Here, AKT1 is linked to endometriosis.