Association between H-ras minisatellite and colorectal cancer risk.
BACKGROUND
The H-ras locus has been suggested to play an important role in susceptibility to cancer. However, the results remain controversial.


METHODS
In order to elucidate the potential role of the H-ras locus in colorectal carcinogenesis, 142 colorectal tumors with matched normal samples were studied for genomic instability and loss of heterozygosity (LOH), and 143 healthy samples of white blood cell DNA were examined by PCR, for H-ras allelic polymorphism.


RESULTS
Nine percent of colorectal cancer patients constitutionally presented at least one rare allele versus 1.4% of healthy individuals (P = 0.0034). The risk of developing colorectal cancer increased significantly with the presence of rare H-ras alleles (odds ratio = 7.10 and 95% confidence interval = 1.92-26.35). The genotype associating one common allele and one rare allele was overrepresented in cancer patients (P < 0.01). No associations were observed between the rare alleles and tumor site or with the aggressiveness of cancer. Low frequencies of LOH (5%) and genetic instability (0.7%) at the H-ras locus were found in our colorectal cancer set.


CONCLUSIONS
Consequently, the presence of uncommon alleles at the H-ras locus appeared to be an informative genetic marker.
Laboratoire de Radioanalyse, Centre Paul Papin, Angers, France.
S
S
Gosse-Brun
S
S
Sauvaigo
A
A
Daver
F
F
Larra
F
F
Kwiatkowski
Y J
YJ
Bignon
D
D
Bernard-Gallon
D000230:Adenocarcinoma / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D003111:Colonic Polyps / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D016001:Confidence Intervals; D004247:DNA / Q000097:blood; D005260:Female; D011905:Genes, ras; D006801:Humans; D007962:Leukocytes / Q000502:physiology; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012016:Reference Values; D012307:Risk Factors
D004247:DNA