Table 1

 Frequency of skewed X inactivation (≥90:10) in patients with breast cancer

Age group (years)
No/total(%)p Value*No/total(%)p Value*No/total(%)p Value*
Probability (p) values ⩽0.06 are in bold. Low risk patients were patients with one close relative (first or second degree) with breast cancer; high risk patients were those with two or more close relatives with breast cancer.
*Patients were compared with controls of their respective age group; p values ⩽0.017 are significant (after Bonferroni correction).
†Patients from Karolinska Hospital.
‡Patients from Huddinge Hospital and Söder Hospital.
Familial†‡12/107(11.2) 0.001 11/113(9.7)0.154/52(7.7) 0.02
    Low risk†‡10/76(13.2) 0.001 7/65(10.8)0.221/29(3.4) 0.02
        Low risk†6/32(18.8) 0.001 3/26(11.5)0.180/12(0.0)0.16
        Low risk‡4/44(9.1) 0.06 4/39(10.3)0.381/17(5.9)0.23
    High risk†‡2/31(6.5)0.254/48(8.3)0.573/23(13.0)0.51
        High risk†2/20(10.0)0.132/34(5.9)0.661/19(5.3)0.17
        High risk‡0/11(0.0)1.002/14(14.3)0.182/4(50.0)0.21
Sporadic‡6/97(6.2)0.2118/132(13.6) 0.02 10/63(15.9)0.35
Controls 7/259(2.7)4/91(4.4)43/202(21.3)