Widespread expression of prostate apoptosis response-4 in nasopharyngeal carcinoma.
BACKGROUND
Prostate apoptosis response-4 (Par-4) augments apoptosis in various tumors, either during apoptotic insult or by ectopic overexpression. However, investigation of Par-4 expression in nasopharyngeal carcinoma (NPC) is lacking.


METHODS
Specimens from patients with NPC, hypopharyngeal carcinoma (HPC), or oral cavity cancer were examined for Par-4 expression using immunohistochemistry. NPC cell proliferation and apoptosis were analyzed using immunohistochemical staining for Ki67, B-cell lymphoma 2 (Bcl-2), and in situ terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick end-labeling (TUNEL) assay, respectively.


RESULTS
Par-4 was ubiquitously expressed in NPC biopsies (96.2%, 25/26) and was significantly higher than in HPC (47.6%, 50/105, p < .0001) and oral cavity cancers (38.7%, 12/31, p < .0001). Remarkably, apoptosis of NPC cells was absent and Par-4 expression was associated with obvious expression of Bcl-2 and Ki67 in all patients tested with NPC.


CONCLUSIONS
Immunohistochemistry results showed widespread expression of Par-4 in NPC and revealed sustainable proliferation of NPC cells regardless of Par-4 expression.
Lee
Jeng-Woei
JW
Institute of Life Science, College of Life Science, Tzu-Chi University, Hualien, Taiwan. jwlee@mail.tcu.edu.tw
Hsiao
Wei-Ting
WT
Lee
Kuei-Fang
KF
Sheu
Lai-Fa
LF
Hsu
Hsue-Yin
HY
Hsu
Lee-Ping
LP
Su
Borcherng
B
Lee
Moon-Sing
MS
Hsu
Yih-Chih
YC
Chang
Chung-Hsing
CH
D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology*; D049109:Cell Proliferation; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; C101296:prostate apoptosis response-4 protein