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

Table 1 Pathologic and immunohistochemical characteristics that were significantly different in BRCA1-associated breast cancers with and without loss of wt BRCA1

Variables	Loss of wt BRCA1	No loss of wt BRCA1	P-value
	N(%)	N(%)
Sample Size	65	12
Histology
Ductal*	59 (90.8)	8 (66.7)	0.043
Ductal/Lobular	4 (6.1)	3 (25)
Other	2 (3.1)	1 (8.3)
Mitoses/10 high power field
0 to 5*	10 (15.4)	8 (66.7)	< 0.001*
6 to 10	14 (21.5)	0
> 10	41 (63.1)	4 (33.3)
Grade
1 (3 to 5 points)	5 (7.7)	5 (41.7)
2 (6 to 7 points)	7 (10.8)	3 (25)
3 (8 to 9 points)*	53 (81.5)	4 (33.3)	0.001*
CK5/6	58	11
Positive	29 (50)	0 (0)	< 0.001*
Negative	29 (50)	11 (100)
CK14	58	9	0.023
Positive	23 (39.7)	0
Negative	35 (60.3)	9 (100)
CK5/6 or CK14	60	12	< 0.001*
Positive	35 (58.3)	0 ((0)
Negative	25 (41.7)	12 (100)
CK5/6 and/or CK14 and/or EGFR	61	12	0.023
Positive	39 (63.9)	3 (25)
Negative	22 (36.1)	9 (75)

Abbreviations: ER, estrogen receptor; CK, cytokeratin; EGFR, epidermal growth factor receptor.
Loss of wt: cancers with LOH with loss of wt BRCA1 allele.
No loss of wt: includes cancers with no LOH and LOH^mut.
*P-value retained significance with Bonferroni adjustment for multiple comparisons.
Percentages calculated by column.

ISSN: 1465-542X