A positive correlation was demonstrated between the SMAD4 and CDH1 genes in biopsy material derived from the eutopic endometrium (Rho = 0.681538, p = 0.000176) and in PBMC patients with endometriosis (Rho = 0.526154, p = 0.006900) (see Figure S1). The gene discussed is SMAD4; the disease is endometriosis.