2 Fanburg-Smith Fanburg-Smith J J Bratthauer Bratthauer G G Miettinen Miettinen M M Osteocalcin and osteonectin immunoreactivity in extraskeletal osteosarcoma: a study of 28 cases Osteocalcin and osteonectin immunoreactivity in extraskeletal osteosarcoma: a study of 28 cases Hum Pathol. The gene discussed is SPARC; the disease is osteosarcoma.