A monoclonal antibody established from the immunization of basal cell carcinoma (BCC) tissues reacts to the intercellular space of BCC and hair follicles.

To detail the histogenetic relationship between basal cell carcinoma (BCC) and hair follicles, a monoclonal antibody, coded as MMKB-1 and established from immunization of mice by human basal cell carcinoma (BCC) tissues, was immunohistochemically studied in tissues of BCC and squamous cell carcinoma (SCC) of the skin, as well as in normal human skin tissues. On 1M-NaCl-split normal human skin tissues, it reacted against both the epidermal and the dermal sides of the basement membrane zone (BMZ). This monoclonal antibody reacted to the BMZ and intercellular space (ICS) of the solid, superficial, and fibrosing types of BCC cell nests, but, in SCC tumor cell nests, it reacted exclusively to the BMZ. Immunoelectron microscopic studies revealed that the corresponding antigen of the monoclonal antibody was distributed in the hemidesmosomes and the anchoring fibrils along the BMZ of the normal human skin and the desmosomes of the BCC cell nest. The monoclonal antibody also reacted to the ICS of the lower outer root sheath and hair matrix. We discussed the histogenesis of BCC and hair follicles, referring to the results of the staining patterns of MMKB-1 monoclonal antibody and to other studies suggesting a histogenetic relationship between BCC and hair follicles.