Evaluation of Bax?2 Positive-Staining in Skin Samples Using Two Immunohistochemical Methods

摘要

BaxΔ2 is a pro-death and tumor suppressor protein that sensitizes cells to certain chemotherapies. Previous diaminobenzidine (DAB)-based staining revealed that Bax?2 is found in all organs, including breast, colon, and skin tissues. In the skin, the Bax?2 positive cells were mainly found in the basal cell layer of the epidermis with a few Bax?2 positive cells in the connective tissue of the dermis, although their cellular identity was unknown. Previous literature has shown that melanin, which is found throughout the cells of the epidermis, is a brown color that provides no visual contrast to the DAB staining. While the DAB-based immunostaining showed cells that appeared to be Bax?2 positive, this result needed to be confirmed. For this, a set of human skin samples from normal and cancerous tissue of various patients was examined. The co-staining of these samples for Bax?2 and basal cells using immunofluorescence revealed that the apparent Bax?2-positve DAB staining in epidermal basal cells and squamous cell carcinoma as false-positive, but the Bax?2 positive cells found in the dermal connective tissue were not false positive—which is consistent with both previous DAB-based and fluorescence-based immunostaining. Using co-immunostaining for Bax?2 with different cellular markers, the Bax2-positive cells in the connective tissue were identified potentially as macrophages and fibroblasts. Further studies are required to confirm the identity of the Bax?2 positive cells in the connective tissue.