Allelic loss on chromosome 18q as a prognostic marker in stage II colorectal cancer.
OBJECTIVE
Loss of heterozygosity (LOH) on chromosome 18q is frequent in colorectal cancer (CRC) and has been associated with poor prognosis in stage II tumors. This study investigated the frequency of LOH in sporadic CRC and its effect on patient prognosis.


METHODS
One hundred forty-four patients were screened for LOH at 18q by polymerase chain reaction using three polymorphic microsatellite markers.


RESULTS
Nineteen patients were excluded because their tumors showed microsatellite instability in at least one marker. Of the remaining 125 patients, 121 were informative in at least one marker; 45% (54 of 121) showed 18q LOH. Five-year survival was 42% in those with 18q LOH and 73% in those without 18q LOH (P = 0.008). Multivariate analysis showed that tumor side (P = 0.0001) and 18q LOH (P = 0.01) were the only independent prognostic factors. Examining markers individually showed that only the lost of D18S474 had a significant influence on survival in patients with stage II CRC (P = 0.016).


CONCLUSIONS
18q LOH indicates an unfavorable outcome in patients with stage II CRC. Our results emphasize the importance of the 18q21.1 region, where several tumor-suppressor genes have been mapped. Microsatellite analysis may be useful in identifying high-risk patients who might benefit from adjuvant therapy.
Martínez-López
E
E
Laboratory of Molecular Biology of Cancer, University Hospital Germans Trias i Pujol, Barcelona, Spain.
Abad
A
A
Font
A
A
Monzó
M
M
Ojanguren
I
I
Pifarré
A
A
Sánchez
J J
JJ
Martín
C
C
Rosell
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005819:Genetic Markers; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis; D016019:Survival Analysis
D005819:Genetic Markers