Table A5.

PIK3CA Mutation Status and pCR by Treatment Group

Treatment and PIK3CA Status	Total pCR
	No		Yes
	No. of Patients	%	No. of Patients	%
Lapatinib
Mutant	23	85.2	4	14.8
WT	74	79.6	19	20.4
Trastuzumab
Mutant	16	80.0	4	20.0
WT	63	71.6	25	28.4
Lapatinib + trastuzumab
Mutant	20	71.4	8	28.6
WT	38	44.2	48	55.8

Abbreviations: pCR, pathologic complete response; WT, wild type.