Trinucleotide repeat polymorphisms in the androgen receptor gene and risk of ovarian cancer.
BACKGROUND
Androgens may play a role in the development of ovarian cancers. Two trinucleotide repeat polymorphisms have been described in exon 1 of the androgen receptor (AR) gene that may affect its function. Previous studies of ovarian cancer and AR repeat polymorphisms have been inconsistent.


METHODS
We analyzed CAG and GGC repeat length polymorphisms in the AR gene using data from a population-based case-control study of ovarian cancer that included 594 cases and 681 controls. Repeat lengths were determined by fluorescent DNA fragment analysis using ABI GeneScan software. Change point models were used to determine appropriate repeat length cutoff points by race (African American versus Caucasian) for both the shorter and longer CAG and GGC repeats.


RESULTS
No relationship was observed between CAG repeat length and ovarian cancer among Caucasians. Among African Americans, having a short repeat length on either allele was associated with a 2-fold increase in ovarian cancer risk (age-adjusted odds ratio, 2.2; 95% confidence interval, 1.1-4.1). Having short CAG repeat lengths for both alleles was associated with a 5-fold increased risk for developing ovarian cancer (age-adjusted odds ratio, 5.4; 95% confidence interval, 1.4-1.7). No relationship with the GGC repeat length polymorphisms was observed.


CONCLUSIONS
These results suggest that having a short CAG repeat length in AR increases ovarian cancer risk in African Americans. The failure to observe this relationship in Caucasians may be due to the rarity of such short CAG alleles in this population or could reflect racial differences in disease etiology.
Schildkraut
Joellen M
JM
Department of Community and Family Medicine, Duke University Medical Center, Box 2949, Durham, NC 27710, USA. schil001@mc.duke.edu
Murphy
Susan K
SK
Palmieri
Rachel T
RT
Iversen
Edwin
E
Moorman
Patricia G
PG
Huang
Zhiqing
Z
Halabi
Susan
S
Calingaert
Brian
B
Gusberg
Alison
A
Marks
Jeffrey R
JR
Berchuck
Andrew
A
D000328:Adult; D001741:Black or African American / Q000235:genetics*; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D005091:Exons; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000208:ethnology; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D010051:Ovarian Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000235:genetics*; D011110:Polymorphism, Genetic; D011159:Population Surveillance; D011944:Receptors, Androgen / Q000235:genetics*; D012042:Registries; D012307:Risk Factors; D018911:Trinucleotide Repeats / Q000235:genetics*; D044465:White People / Q000235:genetics
D011944:Receptors, Androgen