OBJECTIVETo detect the mutation and expression of SH-3BP-2 in Chinese patients of cherubism and to investigate the possible relationship of gene mutation and multinucleated giant cells in lesions.

METHODSGenomic DNA was extracted from paraffin-imbedded tissues and peripheral blood samples of 10 cases of cherubism (6 familial cherubism and 4 sporadic cherubism). SH-3BP-2 mutations were detected by PCR-direct sequencing. The nature of multinucleated giant cells in lesions was detected by enzyme histochemical staining and immunohistochemical staining using paraffin-imbedded tissues sections. The SH-3BP-2 protein was detected by immunohistochemical staining.

RESULTSThree missense mutations (G1520A, G1505A, G1505C) in exon 9 of SH-3BP-2 were identified which led to 3 transitions (Gly420Glu, Arg415Gln, Arg415Pro). There were no abnormalities in exon 3 of SH-3BP-2 except 1 case which had not PCR products. The protein SH-3BP-2, the calcitonin receptor and the tartrate-resistant acid phosphatase were detected in the cytoplasm of all multinucleated giant cells and parts of monokaryon matrix cells in 8 paraffin-imbedded samples.

CONCLUSIONSThe SH-3BP-2 mutation may participate in the differentiation and maturation of osteoclast-like cells in the lesion of cherubism.