Had a tumor under the fingernail, ring finger,left hand,ate part of the bone,do you think it is cancer?

It is unclear what kind of tumor you are referring to and what is meant by ate part of the bone. A diagnosis cannot be made without seeing exactly what is being referred to but if a tumor did in fact infiltrate into bone, there is a possibility of this being.a cancer. The most important step is to follow up with your doctor so a diagnosis can be made-a biopsy would be needed. Best of luck to you!