| Gastric cancer is one of the most common malignant tumor. Colorectal cancer is a common malignant tumor in the gut, which mortality keeps rising. Invasion and metastasis is the most important cause of cancer mortality. The prognosis of the disease is largely dependent on tumor stage at the time of surgery and is poor when development of metastasis has occurred. The process of metastasis contains a series of interaction between cell and cell or cell and matrix. CD44 is a transmembranous cell adhesion molecules which exist in several isoforms arising from mRNA alternative. It plays a role in cell-matrix interaction. It is known to be a major ligand for hyaluronate and to bind collagen, laminin and fibronectin. CD44 directly influence the binding of tumor cell and the extracellar matrix, which at last effect on the invasion and metastasis of tumor.There is increasing evidence that the expression of variants of the glycoprotein CD44 containing exon ll-CD44v6 is related to the the cellular mobility, invasiveness and metastatic potential of gastrointestinal carcinoma, this study was conducted to know the role of the CD44 variant 6 (CD44 v6) in both tumor progression and metastasis of gastric cancer and colorectal cancer.Materials and MethodsA total of 44 gastric cancer and 76 colorectal cancer tissue with their normal mucosa was obtained from tissue resected in surgury during Mar, 2001 and Feb. 2002 in the 1st affiliacted hospital of Zhejiang university. 44 cases of gastric cancer contains 30 male, 14 female, mean 58.1 years old, 30 had limph-node metastasis, 14 had distant metastasis. 76 cases of colorectal cancer, contains 46 male, 30 female,mean 58. 9 years old, 25 being colonic cancer,51 being rectal cancer, 31 had limph-node metastasis, 13 had distant metastasis.In the present study, 44 cases of gastric cancer with normal gastric mucosa and 62 caese of colorectal cancer with there normal mucosa was detected CD44v6 raRNA expression using reverse transcription-polymerase chain reaction(RT-PCR). CD44 v6 was stained immunohistochemically in 44 gastric cancer tissues and 30 corresponding normal tissues, 76 colorectal cancer tissues and 42 corresponding normal tissues. 39 of the colorectal cases were also detected by flow-cytometric analysis.ResultsA little of the normal gastric tissue and colonocytes showed an expression of CD44 v6. The expression of CD44 v6 mRNA and CD44v6(IHC) was significantly higher in gastric cancer and colorectal cancer than in normal tissue.RT-PCR amplification of CD44 v6 mRNA revealed it positively associated with the lymph node metastasis and distant metastasis. There was no correlation between the expression of CD44 v6 mRNA and gross type, histologic type, histologic differentiation and clinical stage of the gastric cancer. Besides, no significant differences were identified between expression frequencies for CD44 v6 in gastric carcinomas and different gross type, histologic type, histologicdifferentiation, lymph node involvement, distant metastasis, and clinical stage of the gastric cancer.Expression of CD44 v6 mRNA in 62 cases of colorectal cancer is significantly higher (88. 9%) in cases with distant metastasis(52.8%) compared with that without distant metastasis, but We found no association between CD44 v6 mRNA and lymph node involvement of colorectal cancer. Expression of CD44 v6 in 76 cases of colorectal cancer was positively associated with the lymph node involvement, but not associated with distant metastasis. There was no correlation between the expression of CD44 v6 mRNA, CD44v6(IHC)and gross type, histologic type, histologic differentiation , Dukes stage of the colorectal cancer.The expression of CD44 v6 (FCM) was significantly higher in gastric cancer and colorectal cancer than in normal tissue. The expression was higher in female than in male. There was no correlation between the expression of CD44 v6 (FCM)and gross type, histologic type, histologic differentiation, lymph node involvement, distant metastasis , Dukes stage of the colorect...
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