ID2 and endometriosis: By intersecting the differentially expressed genes from the following comparisons—5,123 genes from Ect_Bulk vs. Normal, 3,905 genes from Eut_Bulk vs. Normal, 1,566 genes from Ect_stromal vs. Normal_stromal, 1,163 genes from Ect_stromal vs. Normal_stromal, and 108 genes in the TGF-β signaling pathway—we identified five key genes associated with the TGF-β pathway in endometriosis: NBL1, EMP3, ID2, DCN, and THBS1.