Evaluation of PCNA, p53, K-ras and LOH in endocrine pancreas tumors.
OBJECTIVE
The object of this study was to evaluate the characters of the endocrine pancreas tumors including proliferative activity, p53 mutation, K-ras mutation and microsatellite instability.


METHODS
The 13 endocrine tumors of the pancreas were enrolled in this study. There were 8 hypervascular tumors and 4 normo- or hypovascular tumors. All cases were immunohistochemically characterized in paraffin sections for the presence of proliferating cell nuclear antigen and p53 protein. Mutation in K-ras at codon 12 was detected by the Mutant-allele-specific amplification system. Microsatellite instability was examined by using frozen tissues in the 2 cases.


RESULTS
Proliferating cell nuclear antigen labeling index range was 0.00-0.62 (0.26 +/- 0.23). p53 was positive in 4/13 tumors. K-ras codon 12 mutation was not detected in any tumors. PCNA LI was significantly lower in hypervascular tumors (0.16 +/- 0.20) than normo- or hypovascular tumors (0.44 +/- 0.17) (P < 0.05). PCNA LI was significantly lower in the p53-positive tumors (0.48 +/- 0.17) than the p53-negative tumors (0.17 +/- 0.18) (P < 0.05). K-ras codon 12 mutation was not detected in any tumors. Loss of heterozygosity in 3p was detected in 1 tumor.


CONCLUSIONS
Hypervascular endocrine pancreas tumors have low proliferative activity. p53 mutation influences proliferation as the late event of tumor progression.
Sato
T
T
Department of Surgery, Toyama Prefectural Central Hospital, Japan. YIB03163@niftyserve.or.jp
Konishi
K
K
Kimura
H
H
Maeda
K
K
Yabushita
K
K
Tsuji
M
M
Miwa
A
A
D007516:Adenoma, Islet Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D002455:Cell Division; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D016159:Tumor Suppressor Protein p53