TABLE A1.

Univariate Screen to Detect Predictors of Relapse, Death of Any Cause, and Death of Breast Cancer

Predictor Variable	Outcome Variable
	RFS	OS	BCSS
Overall population
pCR v residual disease	0.053	0.583	0.381
PDX engraftment	1.41 × 10 – 6	9.09 × 10 – 6	2.33 × 10 – 6
RCB class	0.008	0.006	0.007
Race (White, Hispanic, other)	0.049	0.103	0.141
Age >53 years	0.392	0.482	0.736
Clinical stage on diagnosis (I, II ,III)	0.02	0.124	0.096
Nodal status (positive or negative)	0.414	0.304	0.528
HR status (HR-low or negative)	0.528	0.833	0.984
HER2 status (±)	0.087	0.014	0.021
Grade (2 or 3)	0.94	0.591	0.647
Size of largest lesion at diagnosis	0.213	0.468	0.419
Preoperative treatment complete (yes/no)	0.768	0.913	0.913
HR-low or negative/HER2– subgroup
pCR v residual disease	0.3	0.938	0.381
PDX engraftment	2.22 × 10 – 6	3.31 × 10 – 5	2.33 × 10 – 6
RCB class	0.015	0.01	0.007
Race (White, Hispanic, other)	0.049	0.082	0.141
Age >53 years	0.672	0.609	0.736
Clinical stage on diagnosis (I, II, III)	0.055	0.105	0.096
Nodal status (positive or negative)	0.595	0.28	0.528
HR status (HR-low or negative)	0.996	0.776	0.984
Grade (2, 3)	0.951	0.581	0.647
Size of largest lesion at diagnosis	0.181	0.216	0.419
Preoperative treatment complete (yes/no)	0.552	0.923	0.913

NOTE. Cox likelihood ratio test P values for statistical significance as a predictor for an event in the overall population and HR-low or negative/HER2-negative subgroup. P < .05 highlighted in bold.

Abbreviations: BCSS, breast cancer-specific survival; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; OS, overall survival; pCR, pathologic complete response; PDX, patient-derived xenograft; RCB, residual cancer burden; RFS, relapse-free survival; TNBC, triple-negative breast cancer.