Immunohistochemical nuclear staining for p53, PCNA, Ki-67 and bcl-2 in different histologic variants of basal cell carcinoma.

Background: Basal cell carcinoma is the most common form of human cancer. Increased expression of p53 has been found in the majority of basal cell carcinomas (BCCs); however, UV-light-induced signature mutations are present in only about 50% of cases. Increased nuclear staining with an immunohistochemical marker of proliferation and apoptosis has been correlated with aggressive behavior in BCC.

Objective: Our purpose was to correlate markers expression of apoptosis (p53 and bcl-2) and cell proliferation (Ki-67 and PCNA) with histological indicators of tumor severity.

Methods: We used immunohistochemical stains for p53, PCNA, and Ki-67, in superficial, nodular and sclerosing BCC, to determine whether the staining patterns differ in these different histologic variants of BCC.

Results: Bcl-2 expression was significant in basal cell carcinomas said to be aggressive (morpheaform and nodular types). Of the studied tumors, 66.7% (n=14) strongly expressed p53. Our results show a greater expression of Ki-67 in nodular and superficial basal cell carcinoma. PCNA showed a strong expression in all types of tumors.

Conclusion: Studies employing molecular and genetic biology techniques, associated with histomorphology, lead to the identification of risk factors in the development of more recurring and aggressive lesions.