Telomeric associations and consistent growth factor overexpression detected in giant cell tumor of bone

Tumor specimens from 15 patients with giant cell tumor (GCT) of bone were cytogenetically analyzed. A subset of five individuals had tumor cells harvested and polyadenylated RNA isolated. Multiple Northern blots were performed utilizing radiolabeled probes for the growth factors TGFβ1, TGFβ2, TGFβ3, and TGFα (TGF, transforming growth factor). RNAs from other types of neoplasms and nonneoplastic cells were examined as controls. The most consistent cytogenetic abnormality detected involved multiple telomeric associations (TAs), most frequently involving the terminus of the long arm of chromosome 19 (19q). Northern blot analysis revealed a consistent expression of TGFβ1 and TGFβ2 with an inconsistent mRNA expression for the other TGFs. There was a relative overexpression of mRNA for TGFβ2. The gene location for TGFβ1 is near the 19q terminus and thus it is speculated that TGFβ may play a role in the neoplastic transformation of GCT.