Triple-negative breast cancer and PTEN (phosphatase and tensin homologue)loss are predictors of BRCA1 germline mutations in women with early-onset and familial breast cancer, but not in women with isolated late-onset breast cancer

Table 1 Characteristics of women tested for germline BRCA1 and BRCA2 mutations

Characteristics	Total		BRCA1		BRCA2		BRCA1 and -2
	n	(%)	n	(%)	n	(%)	n	(%)
Female breast, age at index diagnosis, years
≤30	50	11.6	8	16.0	2	4.0	10	20.0
31-40	164	38.1	17	10.4	13	7.9	30	18.3
41-50	144	33.4	8	5.6	8	5.6	16	11.1
>50	73	16.9	4	5.5	5	6.8	9	12.3
Breast or ovarian cancers in family (first and second degree only)
Female breast	217	50.3	21	9.7	20	9.2	41	18.9
Female ovary	19	4.4	6	31.6	3	15.8	9	47.4
Manchester score
≤10	205	47.6	5	2.4	6	2.9	11	5.4
11-17	146	33.9	16	11.0	10	6.8	26	17.8
≥18	80	18.6	16	20.0	12	15.0	28	35.0
Ancestry
Malay	115	26.7	8	7.0	9	7.8	17	14.8
Chinese	248	57.5	15	6.0	16	6.5	31	12.5
Indian	59	13.7	12	20.3	3	5.1	15	25.4
Others	9	2.1	2	22.2	0	0.0	2	22.2
Referral characteristic
Early onset ≤35 years, regardless of family history	131	30.4	17	13.0	8	6.1	25	19.1
Two cases of breast cancer, one <50 years	126	29.2	10	7.9	11	8.7	21	16.7
Three cases of breast or ovarian cancer	76	17.6	13	17.1	12	15.8	25	32.9
One case of bilateral breast cancer <50 years, in index or first- and second-degree relative	39	9.0	10	25.6	3	7.7	13	33.3
One case of breast and ovarian cancer in same individual in index or first- and second-degree relative	8	1.9	3	37.5	1	12.5	4	50.0
Triple-negative breast cancer, ≤50 years	98	22.7	20	20.4	3	3.1	23	23.5

In total, 431 breast cancer patients were analyzed for germline mutations in BRCA1 and BRCA2 by DNA sequencing and multiple ligation-dependent probe amplification (MLPA) analysis. Table 1 shows the distribution of women according to their age at diagnosis, family history of breast and ovarian cancer in first- and second-degree relatives, Manchester score and self-declared ethnicity, and the prevalence of BRCA1 and BRCA2 mutations in each category.

ISSN: 1465-542X