Table 2.

Results of Mutation Analysis^[Note]

	No. of Cases Analyzed/No. of Mutations(95% CI)
Gene	Invasive	Borderline
BRCA1	109/0 (0%–4%)	77/0 (0%–5%)
BRCA2	98/0 (0%–4%)	74/0 (0%–6%)
hMLH1	100/2 (1%–8%)	64/0 (0%–6%)
hMSH2	100/0 (0%–4%)	64/0 (0%–6%)

Note.—There were five index cases analyzed for mutations in all of the genes but in which details on whether the tumors were borderline or invasive were unknown. In the computation of the 95% CIs, we allowed for a detection sensitivity of 70% for BRCA1 mutations. For the calculation of the confidence limits for BRCA2 mutations, we assumed that 73% of mutations in patients with ovarian cancer occur in the ovarian cancer–cluster region of BRCA2 and that the PTT has an 87% sensitivity (Hogervorst et al. 1995; Takahashi et al. 1996; Tavtigian et al. 1996; Gayther et al. 1997; Hakansson et al. 1997; Breast Cancer Information Core Data Base). In the computation of the confidence limits for the SSCP/HA analysis of the hMLH1 and hMSH2 genes, we assumed a sensitivity of 75%, which is the lowest reported sensitivity of the technique (Orita et al. 1989a, 1989b; Condie et al. 1993; Sheffield et al. 1993).