Objective: The purpose of this study is to evaluate if the potential of the ADC values obtained at 3.0T quantitative DWI imaging could be a biomarker of invasive ductal carcinoma and assess the relationships between ADCs and prognostic factors.Materials and method: From January 2012 to January 2014,all consecutive patients with diagnosed breast cancer confirmed by histological examination and underwent breast 3.0T MRI in our hospital were enrolled in this study.The MRI protocol included both dynamic contrast enhanced and a diffusion weighted imaging sequence with b values of 0 and 600 s/mm2.The ADC values were measured in each index lesions by two radiologists respectively.The relationship between ADC values and tumor size,axillary lymph node metastases,hormonal receptors,and HER2 were analyzed by using T-test.We also compared ADC values in five different tumor subgroups(Luminal A,Luminal B1,Luminal B2,HER2+,Triple negative)defined by combinations of immunohistochemical features using One-way analysis of variance.Results: The final study sample was consisted of 97 patients with 97 pathologically confirmed invasive ductal carcinoma(IDC)lesions not otherwise specified.The mean ages of 97 patients was 55.67±8.57 years,range from 33-72.Significant statistical difference of mean ADC of tumors between the two groups(size≥2cm,size<2cm)was showed(1.15±0.14 mm2/s versus 1.02±0.11 mm2/s,p=0.031).Mean ADC value of axillary lymph node statues between metastasis positive(1.16±0.08 mm2/s)and negative(1.02±0.18 mm2/s)showed significant difference(p=0.023).Mean ADC value of ER positive lesions(1.01±0.15 mm2/s)was significant lower than that of ER negative lesions(1.12±0.19 mm2/s,p=0.041).Mean ADC value of PR positive lesions(1.07±0.18 mm2/s)was significant lower than that of PR lesions(1.12±0.19 mm2/s,p=0.024).Mean ADC of Ki-67 <15%index lesions(1.14±0.18 mm2/s)showed no significant statistical difference from that of Ki-67>15%index lesions(1.11±0.17 mm2/s,p= 0.73).However there was no significant difference between HER2-positive(1.11±0.18 mm2/s)and negative of lesions(1.07±0.17mm2/s,p=0.051).Mean ADC values for Luminal A,Luminal B1,Luminal B2,HER2+,and Triple negative were 0.95±0.07×10-3 mm2/s,0.99±0.11×10-3 mm2/s,1.12±0.15×10-3 mm2/s,1.27±0.11×10-3 mm2/s,1.31±0.71×10-3 mm2/s,respectively.The mean ADC of Triple Negative was the highest in five groups.The mean ADC of Luminal A was the lowest in the five groups.The mean ADC values of Triple Negative was significantly different between other groups(Luminal A,Luminal B1,Luminal B2)(p<0.001),whereas that of no significant difference between Triple Negative and HER2+groups(p=0.275).The mean ADC values of Luminal A was significantly different between other groups(Luminal B2,HER2+,Triple Negative)(p<0.001),whereas that of no significant statistical different between Luminal A and Luminal B1 groups(p=0.109).Conclusions: The ADC values of breast cancer obtained on 3.0T DWI could be associated with important biological features of tumors,which may bear prognostic significance.ADC values detected on 3.0 T DWI showed potential as a new noninvasive imaging biomarker that might be helpful in predicting the biological properties of breast cancers.