Table 1

Percentage of estrogen receptor (ER)-positive breast cancers by grade

ClassN (%)ER+%Pa
Noncarriersb
 Grade 171 (29.7)90.1P1/2 = 0.0024
 Grade 298 (41.0)69.4P1/3 < 0.0001
 Grade 370 (29.3)45.7P2/3 = 0.0006
 Total239 (100)68.6Ptrend < 0.0001
BRCA1 carriersb
 Grade 17 (3.3)71.4P1/2 = 0.070
 Grade 248 (23.1)41.7P1/3 = 0.0004
 Grade 3153 (73.6)15.7P2/3 = 0.0001
 Total208 (100)23.6Ptrend < 0.0001
BRCA2 carriersb
 Grade 15 (5.7)80.0P1/2 = 0.403
 Grade 242 (47.7)95.3P1/3 = 0.297
 Grade 341 (46.6)61.0P2/3 = 0.0001
 Total88 (100)78.4Ptrend = 0.0017
Untestedb
 Grade 186 (14.4)88.4P1/2 = 0.798
 Grade 2239 (40.1)87.0P1/3 < 0.0001
 Grade 3271 (45.5)55.7P2/3 < 0.0001
 Total596 (100)72.9Ptrend < 0.0001
  • a Pa/b (i.e., P1/2, P1/3, and P2/3, column 4) represents the P for the t test between ER+% in classes a and b, therefore P1/2 is the Pvalue for the ttest comparing the ER+% in grade 1 and grade 2 tumors. Ptrend was calculated using the two-sided Cochran-Armitage trend test.

  • b Including all histologies (n = 1131): 992 ductal and 209 nonductal cancers. The 209 nonductal cancers are distributed as follows: noncarrier, n = 54 (22.6% of all noncarriers); BRCA1 carrier, n = 20 (9.6%); BRCA2 carrier, n = 12 (13.6%); untested, n = 123, (20.6%).