Expression of Smac/DIABLO is a novel prognostic marker in lung cancer.
Recently Smac/DIABLO (second mitochondria-derived activator of caspase) has been identified as a proapoptotic protein that inhibits IAPs (inhibitors of apoptosis proteins). Smac is expressed ubiquitously in many organs, including the lung. Here we evaluated the expression of Smac mRNA with real-time reverse-transcription PCR in 88 primary lung cancers and matched normal tissues. Smac mRNA expression in tumor tissues was significantly lower than that in normal tissues (p<0.0001). In squamous cell carcinomas, Smac mRNA expression was significantly lower than that in adenocarcinomas (p=0.0072). Smac mRNA expression in T2-T4 tumors was significantly lower than that in T1 tumors (p=0.0006). The expression of Smac in the tumors of smokers was lower than that in the tumors of non-smokers (p=0.0011). The prognosis of patients with a tumor exhibiting a low expression of Smac mRNA was worse than that in those with a tumor exhibiting high Smac mRNA expression (log-rank test, p=0.047). These results indicate that Smac expression may play a role in the carcinogenesis, progression, and prognosis of primary lung cancer.
Sekimura
Atsushi
A
Department of Surgery II, Nagoya City University, Mizuho, Nagoya 467-8601, Japan. yosfujii@med.nagoya-cu.ac.jp
Konishi
Akimitsu
A
Mizuno
Kotaro
K
Kobayashi
Yoshihiro
Y
Sasaki
Hidefumi
H
Yano
Motoki
M
Fukai
Ichiro
I
Fujii
Yoshitaka
Y
D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007120:Immunochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D012189:Retrospective Studies
D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; C412403:DIABLO protein, human; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger