Is It Possible For 2 Siblings To Be Diagnosed With

Is it possible for 2 siblings to be diagnosed with a sarcoma? Particularly Osteosarcoma. Our 13yo daughter was diagnosed back in 2006 at age 13. the initial tumor was found in her right knee, then she relapsed and a secondary tumor was found in her left knee. she lost her battle at age 17. She tested negative for having the gene that would make it more likely for other family members to get it.
im asking the question because my now 12yo daughter is saying she has knee pain. in her knee. She does play soccer and her knee does not appear to be swollen. We plan on taking her for an xray as a first step tomorrow.