Decreased Peroxisome Proliferator-activated Receptor Gamma Gene Expression is Correlated with Poor Prognosis in Patients with Esophageal Cancer

• Published in: Japanese journal of clinical oncology 2002-07, Vol.32 (7), p.238-243
• Main Authors: Terashita, Yukio, Sasaki, Hidefumi, Haruki, Nobuhiro, Nishiwaki, Tadashi, Ishiguro, Hideyuki, Shibata, Yasuyuki, Kudo, Junzo, Konishi, Shigeru, Kato, Joji, Koyama, Hiroshi, Kimura, Masahiro, Sato, Atsushi, Shinoda, Noriyuki, Kuwabara, Yoshiyuki, Fujii, Yoshitaka
• Format: Article
• Language: English
• Subjects: Esophageal Neoplasms - genetics; Esophageal Neoplasms - mortality; Esophageal Neoplasms - pathology; Esophagus - metabolism; Female; Humans; Immunohistochemistry; Key words: PPARγ – esophageal cancer – prognosis – LightCycler – immunohistochemistry; Lymphatic Metastasis; Male; Prognosis; Receptors, Cytoplasmic and Nuclear - analysis; Receptors, Cytoplasmic and Nuclear - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Survival Rate; Transcription Factors - analysis; Transcription Factors - genetics
• ISSN: 0368-2811; 1465-3621; 1465-3621
• DOI: 10.1093/jjco/hyf056

Background: Peroxisome proliferator-activated receptor gamma (PPARγ) induces apoptosis by ligand stimulation in various tumor cell lines. In esophageal cancer cell lines, PPARγ activation also has suppressed the proliferation. Methods: In 55 primary esophageal squamous cell carcinomas (ESCCs) we examined the correlation between the expression of PPARγ mRNA with prognosis of esophageal cancer patients. The expression of PPARγ mRNA was quantified by real-time reverse transcription polymerase chain reaction using LightCycler. Immunohistochemistry was used to study the expression of PPARγ protein. Results: The expression of PPARγ mRNA was significantly decreased in esophageal cancer cells compared with normal esophageal mucosa (P = 0.0084). Among the clinical factors, PPARγ mRNA expression was lower in the tumors with extensive lymph node metastasis (n4) than those with less extensive lymph node metastasis (n0–3) (P = 0.0059). Patients with low PPARγ mRNA expression had significantly shorter postoperative survival time than those with high PPARγ mRNA expression (P = 0.0191). In immunohistochemistry, PPARγ protein was expressed in the nuclei of cells in some cases and expressed in the nuclei and cytoplasm in others. The expression of PPARγ protein is decreased in esophageal cancer tissue compared with normal esophageal squamous epithelium. However, we could not deduce the apparent relation for the expression between PPARγ mRNA and PPARγ proteins in immunohistochemistry (P = 0.284). Conclusions: In esophageal cancer tissues, the expression of PPARγ was decreased compared with normal esophageal epithelium. The mRNA expression level of PPARγ may be a marker of prognosis after operation in esophageal cancer patients.