TY - JOUR
T1 - Skewed X chromosome inactivation and early-onset breast cancer
AU - Struewing, Jeffrey P.
AU - Pineda, M. A.
AU - Sherman, M. E.
AU - Lissowska, J.
AU - Brinton, L. A.
AU - Peplonska, B.
AU - Bardin-Mikolajczak, A.
AU - Garcia-Closas, M.
PY - 2006/1
Y1 - 2006/1
N2 - Background: Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early-onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study. Methods: We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme Hpall. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as >90% of the signal from one allele in the Hpall digested sample. Results: There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre-menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR=1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR=0.9, 95% CI 0.4 to 2.0. Conclusions: While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.
AB - Background: Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early-onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study. Methods: We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme Hpall. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as >90% of the signal from one allele in the Hpall digested sample. Results: There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre-menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR=1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR=0.9, 95% CI 0.4 to 2.0. Conclusions: While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.
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U2 - 10.1136/jmg.2005.033134
DO - 10.1136/jmg.2005.033134
M3 - Article
C2 - 15923273
AN - SCOPUS:30744462045
SN - 0022-2593
VL - 43
SP - 48
EP - 53
JO - Journal of medical genetics
JF - Journal of medical genetics
IS - 1
ER -