Abstract: YKL-40 is one of mammalian chitnase members and secreted by macrophage， neutrocyte， chondrocyte， endotheliocyte，vascular smooth muscle cell and some entity tumor cells. Immunohistochemical assay has found that YKL-40 is expressed in many human tissues with a varying degree. In healthy young group，the expression of serum YKL-40 is in low level and has no deference between male and female. Studies suggest that there are a high expression of YKL-40 protein in the peritoneum of peritoneal endometriosis，eutopic and ectopic endometrium of adenomyosis，ovarian cancer tissues and endometrial cancer tissues. Serum YKL-40 is elevated in ovarian cancer，endometrial cancer and cervical cancer and is related with shortened survival，elevated serum YKL-40 level before treatment indicates a poor prognosis.

Key words: Glycoproteins, Genital neoplasms, female, Endometrial neoplasms, Ovarian neoplasms, Uterine cervical neoplasms