Expression of polo-like kinase 1 (PLK1) protein predicts the survival of patients with gastric carcinoma.
OBJECTIVE
To assess the prognostic value of polo-like kinase 1 (PLK1), an important regulator of cell cycle progression, in patients with gastric carcinoma.


METHODS
PLK1 expression was determined in 160 gastric carcinoma patients by immunohistochemistry and compared with p53 expression and the proliferating cell nuclear antigen-labeling index (PCNA-LI) to evaluate the effect of PLK1 on tumor progression. Furthermore, PLK mRNA expression was determined in 26 advanced gastric cancer patients by reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
PLK mRNA expression was detected in 25 (96.2%) patients by RT-PCR. Immunohistochemical staining revealed PLK1 expression in 84 (52.5%) patients. There were no significant relationships between PLK1 expression and various clinicopathological factors. PLK1 expression was significantly correlated with the PCNA-LI, but not p53 expression. The prognosis of patients with PLK1-positive tumors was significantly worse than that of patients with PLK1-negative tumors (p < 0.05). Moreover, multivariate analysis revealed that PLK1 expression was an independent prognostic factor. Patients with PLK1-positive and high PCNA-LI tumors showed a significantly poorer prognosis than patients with PLK1-negative and/or low PCNA-LI tumors. Furthermore, the prognosis of patients with PLK1- and p53-positive tumors was significantly worse than that of patients with PLK1- and p53-negative or PLK1-negative and p53-positive tumors.


CONCLUSIONS
PLK1 expression may be a critical indicator of a poor prognosis in patients with gastric carcinoma.
Kanaji
Shingo
S
Department of Surgery, Division of Surgical Oncology, Tottori University School of Medicine, Yonago, Japan.
Saito
Hiroaki
H
Tsujitani
Shunichi
S
Matsumoto
Sachiko
S
Tatebe
Shigeru
S
Kondo
Akira
A
Ozaki
Mitsuhiko
M
Ito
Hisao
H
Ikeguchi
Masahide
M
D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000032:analysis* / Q000235:genetics; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D017346:Protein Serine-Threonine Kinases / Q000032:analysis* / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000737:chemistry / Q000401:mortality* / Q000473:pathology*; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D000097869:Polo-Like Kinase 1
D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D018809:Proliferating Cell Nuclear Antigen; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D000097869:Polo-Like Kinase 1