Expression of CA 50 in normal human skin: comparative study of CEA and CA 19-9.

Normal skin specimens from different body sites were estimated for the expression of CA 50 in comparison with CA 19-9 and CEA. Expression of CA 50 and CA 19-9 was observed in the ductal system and a small part of the secretory portion of eccrine units, but never in any other skin components including apocrine units. CEA was expressed on the ductal and a small part of the secretory portion of apocrine units as well as on those of eccrine units. However, the expression pattern and intensity in eccrine units were different from those of CA 50 or CA 19-9. We concluded that CA 50 was strongly expressed in the normal ductal system of eccrine units and hence could be standardized to stain the eccrine ductal portion and that immunohistochemical comparative studies with CA 19-9 or CEA might be a good methodological technique for discriminating an eccrine or apocrine origin for some skin disorders.