PTEN encoding product: a marker for tumorigenesis and progression of gastric carcinoma.
OBJECTIVE
To detect the expression of PTEN encoding product in normal mucosa, intestinal metaplasia (IM), dysplasia and carcinoma of the stomach, and to investigate its clinical implication in tumorigenesis and progression of gastric carcinoma.


METHODS
Formalin-fixed paraffin embedded specimens from 184 cases of gastric carcinoma, their adjacent normal mucosa, IM and dysplasia were evaluated for PTEN protein expression by SABC immunohistochemistry. PTEN expression was compared with tumor stage, lymph node metastasis, Lauren's and WHO's histological classification of gastric carcinoma. Expression of VEGF was also detected in 60 cases of gastric carcinoma and its correlation with PTEN was concerned.


RESULTS
The positive rates of PTEN protein were 100 %(102/102), 98.5 %(65/66), 66.7 % (4/6) and 47.8 %(88/184) in normal mucosa, IM, dysplasia and carcinoma of the stomach, respectively. The positive rates in dysplasia and carcinoma were lower than in normal mucosa and IM (P<0.01). Advanced gastric cancers expressed less frequent PTEN than early gastric cancer (42.9 % vs 67.6 %, P<0.01). The positive rate of PTEN protein was lower in gastric cancer with than without lymph node metastasis (40.3 % vs 63.3 %, P<0.01). PTEN was less expressed in diffuse-type than in intestinal-type gastric cancer (41.5 % vs 57.8 %, P<0.05). Signet ring cell carcinoma showed the expression of PTEN at the lowest level (25.0 %, 7/28); less than well and moderately differentiated ones (P<0.01). Expression of PTEN was not correlated with expression of VEGF (P>0.05).


CONCLUSIONS
Loss or reduced expression of PTEN protein occures commonly in tumorigenesis and progression of gastric carcinoma. It is suggested that PTEN can be an objective marker for pathologically biological behaviors of gastric carcinoma.
Yang
Lin
L
No.4 Lab, Cancer Institute, The First Affiliated Hospital, China Medical University, Shenyang 110001, China. yxin@mail.cmu.edu.cn
Kuang
Li-Ge
LG
Zheng
Hua-Chuan
HC
Li
Jin-Yi
JY
Wu
Dong-Ying
DY
Zhang
Su-Min
SM
Xin
Yan
Y
D014408:Biomarkers, Tumor; D002681:China; D018450:Disease Progression; D016228:Endothelial Growth Factors / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism / Q000473:pathology; D016147:Genes, Tumor Suppressor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D009367:Neoplasm Staging; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D014408:Biomarkers, Tumor; D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D025521:Tumor Suppressor Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human