A 42-year-old man is diagnosed with an osteosarcoma. His family history is significant for a 37-year-old sister with breast cancer and an uncle with adrenocortical carcinoma. His family physician suspects that he may have Li-Fraumeni syndrome and suggests genetic testing. Which of the following genes is most likely to be mutated if he has the syndrome?
选项：

A:Adenomatous polyposis coli (APC) gene
B:RET
C:p53
D:Phosphatase and tensin homologue (PTEN)