Expression of inducible nitric oxide synthase in colorectal cancer and its association with prognosis.
BACKGROUND
The expression of inducible nitric oxide synthase (iNOS) has been reported to be altered in a number of tumours, but its role in tumour biology is still unclear.


METHODS
iNOS was studied in a series of 157 colorectal carcinoma patients and its relation to tumour grade, stage, cell cycle regulators, cell proliferation as well as survival was assessed.


RESULTS
iNOS intensity was moderate or intense in 37% of the tumours. iNOS intensity and percentage of positive cells were higher in Dukes A and B tumours than in Dukes C and D tumours, and low iNOS expression intensity was related to high histological grade. iNOS expression correlated positively with cell cycle regulators p21 and AP-2. There was also a high iNOS expression intensity and high fraction of iNOS positive cells in tumours with a high amount of tumour infiltrating lymphocytes (TILs). The cancer related survival was significantly lower among patients with a low signal for iNOS and low iNOS percentage in tumour epithelium. In multivariate analysis iNOS was not an independent prognostic factor.


CONCLUSIONS
These results suggest that iNOS has a protective role in colorectal carcinogenesis, but further studies are required to establish the clinical significance of iNOS in colorectal cancer.
Ropponen
K M
KM
Dept. of Pathology and Forensic Medicine, University of Kuopio, Finland.
Kellokoski
J K
JK
Lipponen
P K
PK
Eskelinen
M J
MJ
Alanne
L
L
Alhava
E M
EM
Kosma
V M
VM
D000230:Adenocarcinoma / Q000201:enzymology* / Q000401:mortality; D014408:Biomarkers, Tumor / Q000032:analysis; D018797:Cell Cycle Proteins / Q000032:analysis; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000401:mortality; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D011379:Prognosis; D015996:Survival Rate
D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II