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 2 Characteristics of women tested for germline BRCA1 and BRCA2 mutations

Characteristics	Triple negative				Not triple negative				Pvalue
	n= 110				n= 321
	n	BRCA1	BRCA2	Total (%)	n	BRCA1	BRCA2	Total (%)
With family history
Early onset, ≤35 years old	6	4	0	4 (66.7)	29	3	4	7 (24.1)	0.063^a
>35 years old	32	9	3	12 (37.5)	161	7	13	20 (12.4)	0.0005^b
Overall	38	13	3	16 (42.1)	190	10	17	27 (14.2)	<0.0001^b
Without family history
Early onset, ≤35 years old	25	7	0	7 (28.0)	71	3	4	7 (9.9)	0.045^a
36 to 50 years old	47	3	1	4 (8.5)	60	1	3	4 (6.7)	1.000^a
Overall	72	10	1	11 (15.3)	131	4	7	11 (8.4)	0.131^b
All, regardless of family history or age	110	23	4	27 (24.5)	321	14	24	38 (11.8)	0.001^b
Mean age at diagnosis (years)	40.6				42.0				0.172
Mean number of first-degree relatives	7.2				7.1				0.827
Mean number of affected (breast or ovarian) relatives, first or second degree	0.6				0.8				0.003
Prevalence of BRCA1 mutations		20.9%				4.4%			<0.0001^b
Prevalence of BRCA2 mutations			3.6%				7.5%		0.158^b

^aFisher Exact test. ^bχ² test. The prevalence of germline mutations in BRCA1 and BRCA2 (combined) in the 431 breast cancer patients analyzed, in whom 110 developed triple-negative breast cancer, and 321 did not. Family history includes presence of breast or ovarian cancer in first- and second-degree relatives, bilateral breast cancer in the index patient or relative, or breast and ovarian cancer in the same individual in the index patient or relative. P values were calculated by using Fisher Exact or χ² test, and mean values were calculated by using independent t test.

ISSN: 1465-542X