Aquaporins are
water channels that facilitate passive water transport across cellular membranes following an osmotic gradient and are essential in the regulation of body water homeostasis. Several
aquaporins are overexpressed in
breast cancer, and AQP1, AQP3 and AQP5 have been linked to spread to lymph nodes and poor prognosis. The subgroup
aquaglyceroporins also facilitate the transport of
glycerol and are thus involved in cellular metabolism. Transcriptomic analysis revealed that the three
aquaglyceroporins, AQP3, AQP7 and AQP9, but not AQP10, are overexpressed in human
breast cancer. It is, however, unknown if they are all expressed in the same cells or have a heterogeneous expression pattern. To investigate this, we employed immunohistochemical analysis of serial sections from human invasive ductal and lobular breast
cancers. We found that AQP3, AQP7 and AQP9 are homogeneously expressed in almost all cells in both premalignant in situ lesions and invasive lesions. Thus, potential intervention strategies targeting cellular metabolism via the
aquaglyceroporins should consider all three expressed
aquaglyceroporins, namely AQP3, AQP7 and AQP9.