A small supernumerary marker chromosome or a giant rod chromosome is present in the tumor cells of low grade OS including low grade central OS and paraosteal OS (see below Variants section), carry various potentially pro-cancerous genes, and are thought to contribute to the development of these OS. (See Small supernumerary marker chromosomes and giant rod chromosomes in osteosarcomas)
Familial cases where the deletion of chromosome 13q14 inactivates the retinoblastoma gene is associated with a high risk of osteosarcoma development. Bone dysplasias, including Pagets disease of bone, fibrous dysplasia, enchondromatosis, and hereditary multiple exostoses, increase the risk of osteosarcoma. Li–Fraumeni syndrome (germline TP53 mutation) is a predisposing factor for osteosarcoma development. Rothmund–Thomson syndrome (i.e. autosomal recessive association of congenital bone defects, hair and skin dysplasias, hypogonadism, and cataracts) is associated with increased risk of this disease. Large doses of Sr-90, nicknamed bone seeker, increases the risk of bone cancer and leukemia in animals and is presumed to do so in people.There is no clear association between water fluoridation and cancer or deaths due to cancer, both for cancer in general and also specifically for bone cancer and osteosarcoma. Series of research concluded that concentration of fluoride in water doesnt associate with osteosarcoma. The beliefs regarding association of fluoride exposure and osteosarcoma stem from a study of US National Toxicology program in 1990, which showed uncertain evidence of association of fluoride and osteosarcoma in male rats. But there is still no solid evidence of cancer-causing tendency of fluoride in mice.
Contamination of the fermentation tanks was a persistent problem and in 1951, the company biologist, Ernst Brandl, attempted to solve this by adding phenoxyethanol to the tanks as an anti-bacterial disinfectant. This resulted unexpectedly in an increase in penicillin production: but, the penicillin produced was not benzylpenicillin, but phenoxymethylpenicillin. Phenoxyethanol was fermented to phenoxyacetic acid in the tanks, which was then incorporated into penicillin via biosynthesis. Importantly, Brandl realised that phenoxymethylpenicillin is not destroyed by stomach acid and can therefore be given by mouth. Phenoxymethyl penicillin was originally discovered by Eli Lilly in 1948 as part of their efforts to study penicillin precursors, but was not further exploited, and there is no evidence that Lilly understood the significance of their discovery at the time. : 119–121 Biochemie is now part of Sandoz. Names
There were four named penicillins at the time penicillin V was discovered (penicillins I, II, III, IV), however, Penicillin V was named "V" for Vertraulich (confidential);: 121  it was not named for the Roman numeral "5". Penicillin VK is the potassium salt of penicillin V (K is the chemical symbol for potassium). References
External links
"Penicillin V". Drug Information Portal. U.S. National Library of Medicine.