What Does A Lump In Middle Of Chest Indicate?

My sister has a lump in the middle of her chest that is almost as big as her stomach. Is there any chance that it might be Cancer? She has been having other symptoms: Weight loss, loss of appetite, Chills, bruises appearing all over her body without a reasonable cause, paleness, fever, and she can t go to sleep without taking something. I am really worried, so please will you help me?