Fms-related tyrosine kinase 3 ligand (Flt3L) (p = 0.008), Interleukin-6 receptor alpha (IL-6RA) (p = 0.022), Epidermal growth factor receptor (EGFR) (p = 0.023), Vascular endothelial growth factor receptor 2 (VEGFR-2) (p = 0.026), ICOS ligand (ICOSLG) (p = 0.027), Epididymal secretory protein E4 (HE4) (p = 0.029), C-X-C motif chemokine 10 (CXCL10) (p = 0.032), Receptor tyrosine-protein kinase erbB-2 (ErbB2/HER2) (p = 0.032), E-selectin (SELE) (p = 0.037) and Folate receptor alpha (FR-alpha) (p = 0.049) were underexpressed in women with endometriosis. This evidence concerns the gene ERBB2 and endometriosis.