Expression of the Stem Cell Marker Nestin in Pre/hypertrophic Chondrocytes in Osteochondroma

The pathogenesis of osteochondroma, the most common benign bone tumour, is not fully known. To date, regulation of nestin protein levels in osteochondromas and normal growth plates has not been reported. This study used immunohistochemical analysis to detect nestin protein levels in 48 osteochondromas and 13 normal growth plates (eight fetal and five postnatal). Nestin protein was mainly restricted to prehypertrophic and hypertrophic chondrocytes in osteochondroma. Nestin levels were significantly higher in osteochondromas in adolescents (age range 4 - 18 years, n = 32) than in osteochondromas in young adults (age range 20 - 28 years, n = 11), and significantly higher in osteochondromas in young adults than in those in older adults (age range 40 - 77 years; n = 5). Nestin protein was not present in normal growth plates. The presence of nestin protein parallels the biological behaviour of osteochondromas and is restricted to prehypertrophic and hypertrophic chondrocytes, indicating that these nestin-positive cells may be central to osteochondroma development.