Immunoexpression of Bmi-1, CK15, Bcl-2 in different types of basal cell carcinomas

INTRODUCTION: Basal cell carcinoma (BCC) occurs in aggressive and non-aggressive forms. The expression of immunohistochemical markers varies in different types of BCC. AIM: Immunohistochemical analysis of selected proteins in BCCs. MATERIAL AND METHODS: The immunohistochemical method was used to examine the immunoexpression of Bmi-1, CK15 and Bcl-2 in 56 cases of BCC divided into four groups. RESULTS: Positive Bmi-1 staining 3–4+ level (nodular type) was seen in 91.3% of samples, 4+ (infiltrative) in 92.3%, 4+ (nodular/infiltrative) – 69.2%, 3+ – 30.8%, in BSC 3+ – 42.8%, and 28.6% each for 2+ and 4+. Low grade positivity (0–1+) in CK15 staining was present in 52.1% of nodular BCC, 46.2% – nodular/infiltrative, 92.3% – infiltrative, and 100% – BSC, but levels 2–3+ in nodular BCC in 47.8%, nodular/infiltrative BCC – 53.8%, infiltrative – 7.7%. Bcl-2 positivity (3–4+) was revealed in nodular BCC in 95.6%, (1–2+) in 100% of BSC, infiltrative and infiltrative/nodular BCC, but the lowest (0–1+) in 76.9% of nodular/infiltrative BCC, 71.4% of BSC, and in 38.4% of infiltrative BCC. CONCLUSIONS: Positive Bmi-1 staining was the highest in the aggressive infiltrative subtype of BCCs, whereas the lowest in basosquamous cell carcinomas (BSC). Infiltrative BCC was characterized by a lower level of CK15 expression than nodular BCC and nodular/infiltrative BCC. Differentiation of Bcl-2 expression depended on the type of tumour; the highest level was found in nodular BCC, low grade in nodular/infiltrative and infiltrative BCCs, and BSC.