Abstract: Objective： To study the expression and significance of PTEN， EGFR（epidermal growth factor receptor）and GH（human growth hormone）in endometriosis （EMs），malignant transformed endometrium of EMs and investigate the malignant mechanisms and the characteristics of EMs. Methods：Immunohistochemical S-P method was used to examine the expressions of PTEN，EGFR and GH in the eutopic，ectopic and ectopic malignant transformed endometrium of EMs. Results：The positive rate of PTEN in eutopic，ectopic and ectopic malignant transformed endometrium of EMs of 24 cases were 66. 67％ （16/24），37. 50％ （9/24）and 20. 00％ （1/5）respectively，the positive rate in ectopic and ectopic malignant transformed endometrium of EMs was lower than that of eutopic endometrium and there was statistical difference（P < 0. 05），nevertheless the positive rate between ectopic and ectopic malignant transformed endometrium of EMs had no statistical difference（P＞0. 05）which indicated that the biologic characteristic of the two lesions were similar；The positive rate of GH in eutopic，ectopic and ectopic malignant transformed endometrium of EMs were 87. 18%（102/117），85. 38% （111/130） and 80. 00% （4/5） respectively；The positive rate of EGFR in eutopic，ectopic and ectopic malignant transformed endometrium of EMs were 54. 70% （64/117），89. 23%（116/130）and 80. 00%（4/5）respectively，the positive rate in ectopic and ectopic malignant transformed endometrium of EMs were higher than that of eutopic endometrium. The positive rate of EGFR and GH in ectopic and ectopic malignant transformed endometrium of EMs were similar. Therefore suggested the diagnostic criteria of aEM（atypical endometriosis） and malignant change of EMs. Conclusion：Endometriosis possesses some features of neoplasm such as adhesion，invasion，metastasis and can transform to malignant tumor. GH， EGFR and PTEN play important role in occurrence，development and malignant transformation of EMs. Especially the down regulation or loss of PTEN accompanied simultaneously with the high expression of GH and EGFR can be viewed as the important malignant transformation mark.