Table 3. MDR gene expression level in pre-NAC and post-NAC samples of breast tumor with or without MDR gene loci deletions.

Genes	Sighting point	Tumor with no deletion	Tumor with deletion	p-value
ABCB1	Pre-NACT	3.18 ± 0.73	4.05 ± 1.81	0.584
	Post-NACT	4.29 ± 1.25	0.57 ± 0.28	0.028
ABCB3	Pre-NACT	0.85 ± 0.09	1.15 ± 0.69	0.416
	Post-NACT	0.90 ± 0.22	0.46 ± 0.18	0.253
ABCC1	Pre-NACT	1.33 ± 0, 32	0.83 ± 0.25	0.689
	Post-NACT	1.53 ± 0.37	0.43 ± 0.16	0.047
ABCC2	Pre-NACT	3.54 ± 0.91	2.22 ± 0.72	0.096
	Post-NACT	3.77 ± 1.36	1.55 ± 0.59	0.032
ABCC5	Pre-NACT	2.28 ± 0.43	3.34 ± 1.33	0.194
	Post-NACT	2.70 ± 0.45	3.08 ± 1.35	0.560
ABCG1	Pre-NACT	2.03 ± 0.47	1.12 ± 0.44	0.409
	Post-NACT	1.78 ± 0.39	0.33 ± 0.10	0.009
ABCG2	Pre-NACT	2.02 ± 0.38	1.93 ± 0.88	0.306
	Post-NACT	2.50 ± 0.51	0.78 ± 0.34	0.044
MVP	Pre-NACT	0.51 ± 0.12	0.46 ± 0.21	0.990
	Post-NACT	0.60 ± 0.16	0.21 ± 0.08	0.275

p-value – Mann-Whitney U-test was applied to identify the link between the expression levels of MDR genes in breast tumors and the presence/absence of deletion in the MDR loci. The expression levels of the MDR genes were measured using real-time quantitative PCR (RT-qPCR) based on the TaqMan technology. Expression levels are shown as mean and standard error (M ± SE).