Hello , My Father in law is detected positinve for cancer after the biopsy however we have not been told what cancer it is and what is the origin, they did endoscopy, colonoscopy and did several tumor marker test but as oer them they dont know the origin and treat ment has not been strated yest, they suspect it is stage 4 and have asked for PET SCAN now. we are based in west delhi , plz suggest