NDRG1 mRNA expression analysis in breast tumor tissues (T) and corresponding adjacent tissues (N). (A) NC represents the PCR reaction without DNA. The GAPDH gene was used as internal control. M, Molecular Weight. (B) The PCR products were scanned and analyzed using the Peiqing JS-380 Gel Imaging Analysis System after agarose electrophoresis. The integral absorbance (IA) score for each band was derived from formula IA = average absorbance × area, and the NDRG1 relative expression of each sample was represented in the following way: NDRG1 IA/ GAPDH IA. *P < 0.05.