Table 1 Sibships with two affected sisters. Number of patients with breast or ovarian cancer, calculated frequency, calculated expected pairs concordant for given phenotype assuming random distribution, observed number of concordant pairs, and results of test for independence
From: No Sib Pair Concordance for Breast or Ovarian Cancer in BRCA1 Mutation Carriers
Cancer | Number of patients | Frequency | Expected concordant pairs | Observed concordant pairs | Chi square (p) |
|---|---|---|---|---|---|
breast | 78 | 78/128 = 0.61 | 64×(0.61)2 = 23.8 | 22 | 0.13 (> 0.05) |
ovarian | 50 | 50/128 = 0.39 | 64×(0.39)2 = 9.8 | 8 | 0.32 (> 0.05) |