[Expression of osteopontin mRNA and its protein in colorectal cancer and liver metastatic tissues].
OBJECTIVE
To investigate the expression of osteopontine (OPN) in colorectal cancer and liver metastatic tissues and the significance of OPN in tumorigenesis and liver metastasis of colorectal cancer.


METHODS
The expression of OPN mRNA in 44 samples of colorectal cancer tissues and adjacent normal tissues and 20 samples of liver metastatic tissues was examined by FQ-PCR, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as internal standard. S-P immunohistochemical method was utilized to detect the OPN protein in colorectal cancer and liver metastasis tissues. On the principle that the C(T) value is in inverse proportion to the log value of original copy number of target sequence, OPN C(T)/GAPDH C(T) was used to evaluate the mRNA expression level in different tissues.


RESULTS
The OPN mRNA levels in colorectal cancer tissues were 0.85 approximately 1.47 (kappa +/- s = 1.15 +/- 0.14 ), significantly higher than those in adjacent normal tissues (0.94 approximately 1.47,kappa +/- s =1.32 +/- 0.18) and lower than those in liver metastatic tissues (0.92 approximately 1.30,kappa +/- s =1.07 +/- 0.10) (t =5.81, P =0.00 and t = 2.12,P =0.038), Immunohistochemistry showed that OPN protein was localized in the cytoplasm of colorectal cancer cells, metastatic cancer cells, and normal hepatocytes around metastatic tissue, but not in the normal colorectal tissues around the primary cancer and normal hepatocytes in persons without colorectal cancer.


CONCLUSIONS
The expression of OPN mRNA is the highest in liver metastatic tissues, moderate in primary colorectal cancer tissues, and lowest in adjacent normal tissues of the metastatic liver cancer. OPN protein is located in cytoplasm of colorectal cancer cells. OPN is a potential marker for liver metastasis of colorectal cancer.
Cancer Institute, Zhejiang University, Hangzhou 310009, China.
Ling
L
Ding
Shu
S
Zheng
Jiang
J
Cao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000378:metabolism / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D053495:Osteopontin; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis*; D012795:Sialoglycoproteins / Q000032:analysis / Q000235:genetics*
D012333:RNA, Messenger; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin