METHODS: Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were used to investigate the expression status of ErbB2
protein and gene in 30
osteochondroma tissues and 20 non-neoplastic bone tissues. The association of ErbB2 gene and
protein expression with clinicopathological parameters of
osteochondroma was analyzed by using the χ2 test and Fishers exact test.
RESULTS: ErbB2
protein was found to be over-expressed in 4 of 30 (13.3%)
osteochondromas and 1 of 20 (5%) non-neoplastic bone samples, which were not statistically significant (p=0.336). However, 13 of the 30 (43.3%)
osteochondromas showed ErbB2 gene amplification, which was failed to be observed in any of the non-neoplastic bone tissue. ErbB2 gene amplification in
osteochondroma was significantly higher compared with that in non-neoplastic bone tissue (p=0.001). In addition, the ErbB2 gene amplification was closely associated with clinical pathological parameters of
osteochondroma, including high expression of cellularity (p=0.001), presence of binucleated cells (p=0.001), nuclear pleomorphism (p=0.003), calcification (p=0.002), nodularity (p=0.002),
necrosis (p=0.009) and cartilage thickness (p=0.026). The association of the gene amplification with other clinicopathological parameters of
osteochondroma, including permeation of trabecular bone, cystic/mucoid changes, mitosis, radiographic appearance, cap volume and subtype of
osteochondroma was not observed. The over-expression of ErbB2
protein was not found to be associated with the above stated clinical pathological parameters of
osteochondroma.
CONCLUSION: ErbB2 gene amplification was associated with adverse clinicopathological status of
osteochondroma and could serve as an index for malignant conversion of
osteochondroma. Further research is required to verify the predictive values of ErbB2 for
osteochondroma.
LEVEL OF EVIDENCE: Level IV, Diagnostic Study.