Open AccessHER2 Is Frequently Over‐expressed in Ovarian Clear Cell Adenocarcinoma: Possible Novel Treatment Modality Using Recombinant Monoclonal Antibody against HER2, Trastuzumab
Author(s) -
Fujimura Masaki,
Katsumata Noriyuki,
Tsuda Hiroshi,
Uchi Naoko,
Miyazaki Satomi,
Hidaka Takao,
Sakai Masatoshi,
Saito Shigeru
Publication year - 2002
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.2002.tb01231.x
Subject(s) - trastuzumab , adenocarcinoma , monoclonal antibody , immunohistochemistry , medicine , her2/neu , serous fluid , ovarian cancer , cancer research , antibody , cancer , immunology , breast cancer
Ovarian clear cell adenocarcinoma (CCA) is generally chemo‐resistant. Recently the poor prognosis and resistance to chemotherapeutic agents of HER2/ neu over‐expressing tumors have become clear. Thus, we investigated the expression level of HER2 in surgically resected CCA and ovarian serous adenocarcinoma, endometrioid adenocarcinoma, and mucinous adenocarcinoma specimens, as well as CCA cell lines, by an immunohistochemical method. HER2 was over‐expressed in 42.9% of CCA ( P =0.026, vs. ovarian serous adenocarcinoma), 20.8% of ovarian serous adenocarcinoma, 23.1% of ovarian endometrioid adenocarcinoma, and 30.0% of mucinous adenocarcinoma specimens. Three CCA cell lines, RMG‐1, HAC‐II and KK were also positively stained for HER2. A flow‐cytometric study of HER2 revealed 7.2‐, 6.4‐ and 4.5‐fold greater expression of HER2 than that of normal mammary gland, respectively. Trastuzumab, a humanized recombinant monoclonal antibody against HER2 significantly and dose‐dependently reduced the growth of CCA cell lines in vitro. The extent of the inhibitory effect of trastuzumab was dependent on the expression level of HER2. Trastuzumab also dose‐dependently inhibited the growth of xenografted RMG‐1 tumor. The survival period of trastuzumab‐treated mice was longer than that of the control group. From these findings, trastuzumab appears to be a candidate as a treatment modality for HER2 over‐expressing ovarian CCA.