The nerve fiber density (NFD) of Anti-PGP 9.5 (+) endometriosis-associated nerve of peritoneal endometriosis (EAN-PEM) was significantly higher than NFD of para-endometriotic nerve of peritoneal endometriosis (PEN-PEM) and NFD of nerve of peritoneum of control (N-PC) (p<0.001, p = 0.002, respectively) (Fig 3A, S3 Table). This evidence concerns the gene PGP and endometriosis.