Hello , this is my first post on this forum.My sister has recently been diagnosed with cancer of an unknown primary source ,having never heard of this before I wondered if anyone can enlighten me on this type of cancer please as I am very worried about how poorly my sister is at the moment. She has had 5 of the 12 chemo therapy sessions she has to have ,up to now no specific cancer has been found. I would greatly value any further advice from members please.