In conclusion, by using immunohistochemical analysis of serial sections from human breast cancer samples from invasive lobular and ductal carcinoma, we found that the three aquaglyceroporins—AQP3, AQP7 and AQP9—are homogeneously expressed in the samples from invasive ductal and lobular cancers as well as the regions of ductal and lobular carcinoma in situ. This evidence concerns the gene AQP9 and breast cancer.