How is molecular investiga tion in cancer dx?

PCR of T cells and B cells/Igs monoclonal or polyclonal, FISH also used to see translocation in Ewing sarcoma. Prognosis (Some have poor prognosis, FISH and PCR deect oncogenes HER2/NMYC) Detection of minimal residual disease (BCR-ABL transcript by PCR measures residual chronic myeloid leukemia) Diagnosis of Heriditary Predisposition to cancer (BRCA1, use it for prophylactic surgery/control) Therapeutic-Decision making (according to mutation some respond to BRAF inhibitors (Melanoma) others no response)