Expression of Fas ligand is an early event in colorectal carcinogenesis.
OBJECTIVE
Fas ligand (FasL) is expressed in many cancers and plays an important role in establishing immunologically privileged environments that allow tumors to escape the host's immune surveillance. We investigate the expression of FasL in human colorectal cancer and colorectal adenoma and elucidate the relationship between FasL expression and the clinicopathological characteristics of colorectal cancers.


METHODS
We examined 214 colorectal cancer specimens and 83 colorectal adenoma specimens. Expression of FasL was determined by immunohistochemical staining using a specific monoclonal antibody. We analyzed the relationship between the results of FasL expression and clinicopathological data statistically.


RESULTS
FasL expression was detected in 173 (80.8%) of 214 colorectal carcinomas and 34 (40.9%) of 83 colorectal adenomas. The status of FasL expression in colorectal carcinoma was independent of clinicopathological features including tumor stage, histologic grade, lymphatic invasion, venous invasion, lymph node metastasis, liver metastasis, and Dukes stage. In colorectal adenoma, FasL expression was more frequently observed in high-grade atypia than in low-grade atypia (P = 0.05).


CONCLUSIONS
FasL expression is commonly observed not only in cancer but also in highly dysplastic tissue. These observations suggest that FasL expression may be an important event in the transformation process leading to adenocarcinoma.
Department of Surgery, Niigata University School of Medicine, Niigata, Japan.
M
M
Shimoyama
T
T
Kanda
L
L
Liu
Y
Y
Koyama
T
T
Suda
Y
Y
Sakai
K
K
Hatakeyama
D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology; D000236:Adenoma / Q000737:chemistry* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D053222:Fas Ligand Protein; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008562:Membrane Glycoproteins / Q000032:analysis / Q000096:biosynthesis*; D009367:Neoplasm Staging
C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins