Using CRP purified from the samples taken from patients with systemic lupus erythematosus (CRPSLE), acute lymphoblastic leukaemia (CRPALL), tuberculosis (CRPTB), visceral leishmaniasis (CRPVL), osteogenic sarcoma (CRPOS) and Cushing’s syndrome, the authors demonstrated the presence of sugars such as sialic acid, glucose, galactose, mannose in CRPs, and revealed differences in CRP carbohydrate and amino acid composition between different samples. This evidence concerns the gene CRP and osteosarcoma.