title: Influence of FasL gene expression on hepatic metastasis of colorectal carcinoma.
abstract: BACKGROUND
  FasL expression was reported to be associated with hepatic metastasis of colorectal cancer. The aim of this study was to study FasL gene expression in colorectal carcinoma and its influences on biological behavior and hepatic metastasis of colorectal carcinoma.
  
  
  METHODS
  FasL gene expressions were examined with reverse transcriptase-polymerase chain reaction (RT-PCR) in the primary focus of colorectal carcinoma, adjacent cancerous mucosae, and metastasized liver focus from colorectal cancer. HR-8348 cells of human rectal cancer cell line were transfected with FasL cDNA. Cell growth suppression rate and response to 5-FU and carboplatin were observed and analyzed with the MTT method.
  
  
  RESULTS
  FasL gene expression was detected in the primary focus of colorectal cancer (n=58), adjacent cancerous mucosae (n=58), and metastasized hepatic tumor tissues (n=28). The positive rate of FasL expression was 24% (14/58), 8% (5/58), and 100% (58/58) in the primary focus, adjacent cancerous mucosae and metastasized hepatic tumor tissues respectively. FasL expression rate in the metastasized hepatic tumor tissues was higher than that in the primary focus (X(2)=43.49, P<0.01) and adjacent cancerous mucosae (X(2)=57.66, P<0.01). In a group of patients with hepatic metastasis, the FasL expression rate in primary focus was higher than that in patients without hepatic metastasis (X(2)=3.96, P<0.05). In vitro study positive expression of FasL was shown in transfected HR-8348 cells. When 5-FU or carboplatin was added, there was a significant difference in growth suppression rate between FasL positive and controlled cancer cells (t=9.02, t=11.93, P<0.01). Under the same concentration of chemotherapeutic agents, the survival rate of FasL positive HR-8348 cells was higher than that of controlled cells.
  
  
  CONCLUSIONS
  FasL positive cancer cells are powerfully resistant to chemotherapeutic agents. The expression of the FasL gene in colorectal cancer cells is related to immune evasion to escape from being killed by immune cells, showing stronger drug-resistance, and it facilitates hepatic metastasis.
authors.affiliation: Department of General Surgery, Beijing Military Commend General Hospital, Beijing 100700, China. shiyongli@cnope ration.com
authors.forename: Shi-Yong
authors.initials: SY
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.forename: Ping
authors.initials: P
authors.lastname: An
authors.forename: Jia-Chen
authors.initials: JC
authors.lastname: Wei
authors.forename: Fu-Yi
authors.initials: FY
authors.lastname: Zuo
authors.forename: Hui-Yun
authors.initials: HY
authors.lastname: Cai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology; D016190:Carboplatin / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D018076:DNA, Complementary / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D053222:Fas Ligand Protein; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000556:secondary; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D008875:Middle Aged; D014162:Transfection / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D018076:DNA, Complementary; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D016190:Carboplatin; D005472:Fluorouracil