Grade-specific prostate cancer associations of IGF1 (CA)19 repeats and IGFBP3-202A/C in blacks and whites.
Carrying the cytosine-adenosine (CA)19 repeat polymorphism in insulin-like growth factor-1 (IGF1) is associated with lower serum proteins and decreased prostate cancer risk. Carrying the -202A/C genotype in insulin-like growth factor binding protein-3 (IGFBP3) also has been associated with lower serum levels of the binding protein. However, the association between this variant and prostate cancer is inconsistent. To test the hypothesis that inconsistencies are partly due to cancer grade-specific differences in strength and direction of associations, we reanalyzed data from our previous Durham Veterans Administration Hospital study of blacks and whites comprising 47 cases (19 African Americans) with Gleason sum > or = 7, 50 cases (30 African Americans) with Gleason sum < 7 and 93 controls (49 African Americans). Compared to controls, the association between carrying the IGFBP3 C allele and prostate cancer risk was in OR(Low-Gleason) = 4.0; 95% CI: 1.4-12.3 compared to OR(High-Gleason) = 1.0; 95% CI: 0.4-2.2. Association patterns were similar in African Americans (OR(Low-Gleason) = 3.6; 95% CI: 1.0-13.2 vs. OR(High-Gleason) = 1.4; 95% CI: 0.4-2.3) and whites (OR(Low-Gleason) = 5.6; 95% CI: 0.6-49.0 vs. OR(High-Gleason) = 0.6; 95% CI: 0.2-2.2). The inverse association between carrying the IGF1 (CA)19 repeat variant did not vary by grade or ethnicity. If confirmed in larger studies, these findings support the hypothesis that the association between IGFBP3 C allele and prostate cancer is grade specific in both ethnic groups.
Hoyo
Cathrine
C
Department of Community and Family Medicine, Hanes House-Room 347, Trent Drive, Box 2914, Medical Center, Duke University Medical Center, Durham, NC 27710, USA. hoyo0001@mc.duke.edu
Grubber
Janet
J
Demark-Wahnefried
Wendy
W
Marks
Jeffrey R
JR
Freedland
Stephen J
SJ
Jeffreys
Amy S
AS
Grambow
Steven C
SC
Wenham
Robert M
RM
Walther
Philip J
PJ
Schildkraut
Joellen M
JM
D000328:Adult; D001741:Black or African American / Q000235:genetics*; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000235:genetics*; D014481:United States / Q000453:epidemiology; D044465:White People / Q000235:genetics*
D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3