Evaluation of Carbonic Anhydrase IX and Serum Antioxidant Enzymes in Patients With Periocular Basal Cell Carcinoma.

[PURPOSE] The identification of novel pathways in the etiopathogenesis of basal cell carcinoma (BCC) holds promise for the development of innovative therapeutic strategies. This study investigates the immunohistochemical expression of carbonic anhydrase IX (CA-IX) in periocular BCC, as well as the levels of CA-IX and key antioxidant enzymes in serum.

[METHODS] Fifteen patients with periocular BCC and 18 age- and gender-matched individuals undergoing upper eyelid blepharoplasty were prospectively enrolled. Immunohistochemical analysis of CA-IX expression was performed on tumor tissue excised with clear surgical margins of at least 2 mm, as well as on normal eyelid tissues from the control group. Serum levels of superoxide dismutase 1, catalase, glutathione peroxidase 1, and CA-IX were measured in both groups preoperatively and 1 month postoperatively in the BCC group, using the enzyme-linked immunosorbent assay method.

[RESULTS] In the BCC group, preoperative serum CA-IX levels were significantly higher, while serum glutathione peroxidase 1, catalase, and superoxide dismutase 1 levels were significantly lower compared with the control group (p = 0.001). CA-IX was immunohistochemically positive in 11 of 15 (73%) BCC patients. One month after surgery, an increase in superoxide dismutase 1 and glutathione peroxidase 1 levels and a decrease in CA-IX levels were observed in BCC patients (p < 0.05).

[CONCLUSIONS] Our findings suggest that CA-IX is strongly expressed in periocular BCC tissues and may also serve as a systemic marker, given its elevated serum levels. The lower levels of antioxidant enzymes may be an indicator of possible systemic oxidative stress in BCC patients.