<unk> s may be used for the following purposes: *Screening for common cancers on a population basis. Broad screening for all or most types of cancer was originally suggested but has since been shown not to be a realistic goal. Screening for specific cancer types or locations requires a level of specificity and sensitivity that has so far only been reached by Example: elevated prostate specific antigen suggests that is used in some countries to screen for prostate cancer. *Monitoring of cancer survivors after treatment, detection of recurrent disease. Example: elevated AFP in a child previously treated for teratoma suggests relapse with endodermal sinus tumor. *Diagnosis of specific tumor types, particularly in certain brain tumors and other instances where biopsy is not feasible. *Confirmation of diagnosis to verify the characteristics such as size and aggressiveness of a tumor and thereby to help in the evaluation of a suitable treatment schedule. *Staging: some<unk> s are included in the staging procedures for some tumor localizations. *Prognosis to plan the treatment when used pre-treatment and to help the patient to plan his future when used after the operation of cure. *To verify the effect of treatment to change the treatment if ineffective. *As companion diagnostic to verify if the treatment is suited for the type or subtype of tumor particularly in personalized medicine. As stated in the BMJ 2009,<unk> s should not generally be used for the purpose of diagnosis of cancers, as opposed to monitoring purposes in certain cancers, or in certain cases, for screening purposes. The use of these tests without understanding their utility has resulted in inappropriate use of<unk>  blood tests, which has resulted in inappropriate over-investigation for cancers.
Tumor marker
Biomarker
Biomarker 
Tumor antigen
Lineage markers
Tumor metabolome
Hormone
Cytotechnology