Table 1. Statistical analysis and combination index (CI) values.

RPMI-8226	Concentration (nM)		Viability		Apoptosis
	PPP	ABT	s	CI	S	CI
	125	250	**	0.7	***	0.63
	125	500	**	0.6	*	0.77
	125	1000	*	0.6	**	0.82
	250	250	**	0.9	***	0.74
	250	500	***	0.8	***	0.64
	250	1000	***	0.7	***	0.67
	500	250	ns	nd	ns	nd
	500	500	*	0.6	*	1.03
	500	1000	**	0.6	**	1.03
OPM-2	Concentration (nM)		Viability		Apoptosis
	PPP	ABT	s	CI	s	CI
	125	250	ns	nd	*	0.64
	125	500	ns	nd	**	0.61
	125	1000	ns	nd	*	0.67
	250	250	***	0.7	*	0.78
	250	500	**	0.7	*	0.9
	250	1000	**	0.6	*	0.59
	500	250	*	0.7	ns	nd
	500	500	*	0.6	***	0.67
	500	1000	*	0.6	***	0.62

Significance and CI values were calculated for the different drug concentrations. Statistical significance was evaluated with a Mann-Whitney test using GraphPad Prism 5.0 software. ns = not significant, * p <0.05, ** p <0.01, *** p<0.005 when compared to both single agents. CI values were calculated by the Chou and Thalalay method using CompuSyn 1.0 software (nd = not determined, CI. 1 = synergistic).