Prevalence and predictors of loss of wild type BRCA1 in estrogen receptor positive and negative BRCA1-associated breast cancers

Table 2 Pathologic characteristics and their association with loss of wt BRCA1 in ER-positive and ER-negative BRCA1-related breast cancers

Variable	ER+			ER-
	Loss of wt BRCA1 N(%)	No loss of wt BRCA1 N(%)	P-value	Loss of wt BRCA1N(%)	No loss of wt BRCA1 N(%)	P-value
Sample Size	34	8		31	4
First cancers	24 (70.6)	8 (100)		28 (90.3)	2 (50)
Mean age (range)	45.2 (29 to 68)	50.1 (33 to 72)	0.51	42 (28 to 73)	33.5 (31 to 36)	0.14
Second cancers	10 (29.4)	0		3 (9.7)	2 (50)
Mean age (range)	48.7 (34 to 63)			56 (53 to 61)	57 (56 to 58)
Histology
Ductal*	29 (85.3)	4 (50)	0.05	30 (96.8)	4 (100)	1.00
Ductal/Lobular	3 (8.8)	3 (37.5)		1 (3.2)	0
Other	2 (5.9)	1 (12.5)		0	0
Mitoses/10 high power field
0 to 5*	9 (26.5)	8 (100)	< 0.001*	1 (3.2)	0	1.00
6 to 10	12 (35.3)	0		2 (6.5)	0
> 10	13 (38.2)	0		28 (90.3)	4 (100)
Grade
1 (3 to 5 points)	5 (14.7)	5 (62.5)		0	0
2 (6 to 7 points)	6 (17.6)	3(37.5)		1 (3.2)	0
3 (8 to 9 points)*	23 (67.6)	0	< 0.001*	30 (96.8)	4 (100)	1.00
Geographic Necrosis/Fibrotic Focus
Yes	9 (26.5)	0	1.00	22 (71.0)	2 (50)	0.574
No	25 (73.5)	8 (100)		9 (29.0)	2 (50)
Margins
Invasive	29 (85.3)	8 (100)	1.00	15 (48.4)	2 (50)	1.00
Pushing/Circumscribed	5 (14.7)	0		16 (51.6)	2 (50)
Lymphocyte Infiltrate
Moderate/Severe	4 (11.8)	0	1.00	13 (41.9)	2 (50)	1.00
None/Mild	30 (88.2)	8 (100)		18 (58.1)	2 (50)
PR
Positive*	29 (85.3)	8 (100)	1.00	1 (3.6)	0	1.00
Positive	26 (76.5)	7 (87.5)		0
Low Positive^a	3 (8.8)	1 (12.5)		1 (3.6)
Negative	5 (14.7)	0		27 (96.4)	4 (100)
Unknown	0	0		3 (9.8)	0
Her2/Neu IHC
Positive	1 (2.9)	0	1.00	0	0	1.00
Negative	24 (70.6)	7 (87.5)		25 (80.6)	3 (75)
Her2/Neu FISH
Positive	1 (2.9)	1 (12.5)		0	1 (25)
Negative	6 (17.6)	0		5 (16.1)	0
Equivocal^d	2 (5.9)	0		1 (3.2)	0

Abbreviations: ER, estrogen receptor; PR, progesterone receptor; IHC, immunohistochemistry; FISH, fluorescence in situ hybridization.
Loss of wt: cancers with LOH with loss of wt BRCA1 allele.
No loss of wt: includes cancers with no LOH and LOH^mut .
Percentages calculated by column.
^a Low PR positive: 1 to 10% cells show nuclear staining for PR.
^b HER2 positive: HER2:CEP17 ratio by FISH > 2.2 or IHC 3+ (no FISH performed).
^c HER2 negative: HER2:CEP17 ratio by FISH < 1.8 or IHC < 3+ (no FISH performed).
^d HER2 equivocal: HER2:CEP17 ratio by FISH 1.8 to 2.2.
* P-value retained significance with Bonferroni adjustment for multiple comparisons.

ISSN: 1465-542X