Figure 3. Breast tissue immunohistochemistry (IHC): a, normal mammary duct IHC using antibodies against the basal keratins 5/6. b, normal mammary duct IHC using antibodies against the luminal keratins 8/18 (adjacent tissues sections were used in 3a and 3b). c, tumor Stanford 16 using IHC with antibodies against keratins 8/18. d, tumor New York 3 using IHC with antibodies against keratins 5/6.