The expression of murine double minute 2 is a favorable prognostic marker in esophageal squamous cell carcinoma without p53 protein accumulation.
BACKGROUND
Murine double minute 2 (MDM2) is an oncoprotein that inhibits the function of p53 tumor-suppressor protein. Although there have been a few reports on MDM2 gene abnormalities, there has been no investigation into expression of the product of this gene in esophageal squamous cell carcinoma. Thus, the clinicopathological and prognostic significance of the product of the MDM2 gene is as yet unknown.


METHODS
MDM2 protein expression status was analyzed in surgically resected materials by immunohistochemical procedures.


RESULTS
The expression of MDM2 significantly correlated inversely with tumor size, depth of invasion, lymph node metastasis, lymphatic vessel invasion, and stage of disease. However, the expression of MDM2 correlated with neither p53 protein accumulation status nor Ki-67 labeling index. The prognosis with MDM2-positive status was significantly better than that with MDM2-negative status for patients with p53-negative tumors, but not in those with p53-positive tumors. Moreover, multivariate analysis showed that the expression of MDM2 was an independent prognostic factor in patients with p53-negative tumors.


CONCLUSIONS
These findings indicate that MDM2 immunohistochemical analysis may provide useful information concerning the prognosis in esophageal squamous cell carcinoma patients with p53-negative tumors.
Saito
Hiroaki
H
First Department of Surgery, Tottori University School of Medicine, 36-1 Nishi-cho, Yonago 683-8504, Japan. KotoriSai10@aol.com
Tsujitani
Shunichi
S
Oka
Shinichi
S
Ikeguchi
Masahide
M
Maeta
Michio
M
Kaibara
Nobuaki
N
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology*; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009687:Nuclear Proteins; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D051736:Proto-Oncogene Proteins c-mdm2; D016159:Tumor Suppressor Protein p53
D014408:Biomarkers, Tumor; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2