Beta-catenin, frizzled-2, BMP-4, osteopontin, osteocalcin, and osteonectin expression in calcifying basal cell carcinoma

Background: Although basal cell carcinoma (BCC) is the most common human skin tumor, with calcification reportedly taking place in about 20% of all BCC cases, the pathogenesis of calcification in BCC has not yet been studied. Objective: The purpose of this study was to evaluate factors related to the pathogenesis of calcification in BCC. Methods: We performed immunohistochemical staining for β-catenin, frizzled-2, BMP-4, osteopontin, osteocalcin, and osteonectin using frozen skin tissue from 15 cases of BCC with calcification and 11 cases of BCC without calcification. Results: The expression of β-catenin showed positive in 14 of the 15 cases in BCC with calcification, but negative in all 11 cases of BCC without calcification. The expression of frizzled-2 was observed hi 14 of the 15 cases in BCC with calcification, and in 10 of the 11 cases in BCC without calcification. The difference did not reach statistical significance (p=0.236). The expression of BMP-4 was observed in all 26 samples of BCC, but the intensity of expression did not reach statistical significance between the two groups (p=0.293). Furthermore, osteopontin and osteocalcin showed no statistical significance between two the groups (p=0.567, p=0.401). The expression of osteonectin was observed in all of the BCC cases, and was stronger in BCC with calcification than in BCC without calcification (p=0.042). Conclusion: We suggest that the calcification in BCC might be related to the increase of β-catenin expression and that osteonectin might also influence the process of calcification in BCC.