Table 2.

Demographics of study population by DNMT3b genotype

CC, n (%)CT, n (%)TT, n (%)Total
Cancer status
    Colorectal cancer patients12 (16.2)45 (60.8)17 (23.0)74
    Unaffected MMR mutation carriers28 (38.9)27 (37.5)17 (23.6)72
Gender
    Male17 (24.7)37 (53.6)15 (21.7)69
    Female23 (29.9)35 (45.4)19 (24.7)77
MMR gene mutated
    MLH114 (26.9)23 (44.2)15 (28.9)52
    MSH226 (27.7)49 (52.1)19 (20.2)94
MMR gene mutation type
Truncation/deletion33 (28.9)57 (50.0)24 (21.1)114
    Missense7 (21.9)15 (46.9)10 (31.2)32
Ethnicity/race
    Caucasian36 (29.5)60 (49.2)26 (21.3)122
    African American08 (61.5)5 (38.5)13
    Hispanic4 (40)4 (40)2 (20)10
    Asian001 (100)1
    All subjects40 (27.4)72 (49.3)34 (23.3)146
Allele frequency
    C allele0.5205
    T allele0.4795
Age of onset for colorectal cancer (y)*
    75% of subjects cancer-free47374139
    50% of subjects cancer-free71504850
    25% of subjects cancer-free5963
    Time at risk1,7403,1821,4866,408
    Range23-7723-8428-8423-84
  • NOTE: All participants were confirmed carriers of a HNPCC-related MMR mutation.

  • * The age of onset is the age at first diagnosis for colorectal cancer patients and the age at blood draw for unaffected MMR mutation carriers.

  • The age of onset values were determined from Kaplan-Meier estimates, with the median age of onset defined as the age at which 50% of the population is cancer-free.