TY - JOUR
T1 - Decreased expression of RIZ1 and its clinicopathological significance in epithelial ovarian carcinoma
T2 - Correlation with epigenetic inactivation by aberrant DNA methylation
AU - Akahira, Jun Ichi
AU - Suzuki, Fumihiko
AU - Suzuki, Takashi
AU - Miura, Ikumi
AU - Kamogawa, Noriko
AU - Miki, Yasuhiro
AU - Ito, Kiyoshi
AU - Yaegashi, Nobuo
AU - Sasano, Hironobu
PY - 2007/11
Y1 - 2007/11
N2 - The retinoblastoma protein-interacting zinc finger gene (RIZ1) is considered a tumor suppressor gene. The purpose of the present study was to examine the expression of RIZ1 and evaluate its clinicopathological significance in ovarian carcinoma. Immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed for RIZ1 and its clinicopathological significance was examined. DNA methylation status of RIZ1 was also studied. All (6/6) of the normal, 5/9 of benign, and 4/9 of borderline tissues were positive for RIZ1 protein. In ovarian cancer tissues 32.9% (54/164) were positive for RIZ1. Decreased expression of RIZ1 was significantly correlated with histological subtypes (P < 0.0001), high tumor grade (P = 0.0153) and advanced clinical stage (P = 0.0345), and high Ki67 index (P = 0.0117) but was not associated with the overall prognoses of the patients (P = 0.519). The presence of methylated band was detected in 2/9 cell lines, and 5/69 ovarian cancer tissues. Median values of relative RIZ1 expression in cell lines with methylation were significantly lower than those without methylation (P = 0.0404), and treatment of 5-aza-2′deoxycitidine resulted in demethylation and re-expression of RIZ1. Reduced expression of RIZ1 may play an important role in the pathogenesis and/or development of epithelial ovarian carcinoma, and is considered to be caused in part by aberrant DNA methylation.
AB - The retinoblastoma protein-interacting zinc finger gene (RIZ1) is considered a tumor suppressor gene. The purpose of the present study was to examine the expression of RIZ1 and evaluate its clinicopathological significance in ovarian carcinoma. Immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed for RIZ1 and its clinicopathological significance was examined. DNA methylation status of RIZ1 was also studied. All (6/6) of the normal, 5/9 of benign, and 4/9 of borderline tissues were positive for RIZ1 protein. In ovarian cancer tissues 32.9% (54/164) were positive for RIZ1. Decreased expression of RIZ1 was significantly correlated with histological subtypes (P < 0.0001), high tumor grade (P = 0.0153) and advanced clinical stage (P = 0.0345), and high Ki67 index (P = 0.0117) but was not associated with the overall prognoses of the patients (P = 0.519). The presence of methylated band was detected in 2/9 cell lines, and 5/69 ovarian cancer tissues. Median values of relative RIZ1 expression in cell lines with methylation were significantly lower than those without methylation (P = 0.0404), and treatment of 5-aza-2′deoxycitidine resulted in demethylation and re-expression of RIZ1. Reduced expression of RIZ1 may play an important role in the pathogenesis and/or development of epithelial ovarian carcinoma, and is considered to be caused in part by aberrant DNA methylation.
KW - Immunohistochemistry
KW - Methylation
KW - Ovarian cancer
KW - RIZ1
UR - http://www.scopus.com/inward/record.url?scp=35148883432&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35148883432&partnerID=8YFLogxK
U2 - 10.1111/j.1440-1827.2007.02169.x
DO - 10.1111/j.1440-1827.2007.02169.x
M3 - Article
C2 - 17922684
AN - SCOPUS:35148883432
SN - 1320-5463
VL - 57
SP - 725
EP - 733
JO - Acta Pathologica Japonica
JF - Acta Pathologica Japonica
IS - 11
ER -
