Will Blood-work, WBC and RBC be abnormal if you have cancer?

Dear Ask The Doctor: If a person has active cancer in their body would their bloodwork be out of normal range, maybe WBC or Rbc?

Dear Ronnie: An abnormal blood-work may certainly make a physician suspicious of cancer if there is presence of associated signs like weight loss, night sweats etc. Blood cancers can be detected by a complete blood count which may have to be confirmed by a bone marrow biopsy. Test for proteins and immunoglobulins by electrophoresis may help in detecting multiple myeloma. Tumor marker tests detect cancers of the ovaries, thyroid and prostate. Though blood tests make the physician suspicious of cancer in the body, it is only by a biopsy and study of the cell that cancer is diagnosed.