Based on synonyms in MeSH and EMTREE databases and assuming hyphenated terms will retrieve hyphenated terms as well as those with spaces.
osteopontin OR bone-sialoprotein-1 OR Bone-Sialoprotein-I OR SPP1 OR SPP-1 OR secreted-phosphoprotein-1 OR Secreted-Phosphoprotein-I OR Sialoprotein-1 OR Sialoprotein-I OR Uropontin