Exam 3 Tumor Markers

• Detect and monitor cancer or effectiveness of treatment • Markers are produced by tumor directly or as an effect of tumor on healthy tissue • Concentration increases with tumor progression, highest levels when tumors metastasize

• Enzymes • Serum proteins • Hormones & metabolites • Oncofetal antigens • Receptors

• Levels of certain enzymes correlate with tumor burden

• ALP: bone, liver, intestine • Amylase: pancreas • LD: liver, lymphomas • ACP: prostate

Multiple myeloma light chains found in urine

• ACTH: pituitary adenoma and ectopic lung tumor • HCG: testicular tumor • ADH: lung carcinoma • Catecholamines: neuroblastoma

• Carcinoembryonic antigen (CEA) – colorectal * Alpha-fetoprotein (AFP) – hepatocellular or testicular

• ERA – estrogen receptor assay • PRA – progesterone receptor assay - Presence indicates that tumor will likely respond to treatment

• Screening populations at risk • Diagnosis • Prognosis • Monitoring response to treatment • Detection of recurrence

• Standardization between test methods or instruments is not as good as for other common assays • Comparisons from two different assays can be dangerous due to differences in: o Antibody specificity o Assay design and diversity o Lack of standard reference material o Variation in reference ranges • Example: variation in PSA results from two different assays o Testing done on “access” was consistently higher (1.23x) than testing done on “centaur”

• Immunoassay - most common • Advantage: ability to automate testing • May show the hook effect

Hepatocellular or testicular cancer

Ovarian tumors

Colorectal cancer - > 10 suggestive of disease, > 20 assume metastasis

Testicular cancer

prostate cancer • can be elevated in infection, irritate, benign prostate enlargement • pts with prostate cancer have a lower % of free PSA

< 4ng/mL

metastatic breast cancer

elevated in recurrent breast cancer

hereditary breast-ovarian tumor syndrome

localized primary tumor

invasion of primary tumor through epithelium and into blood vessels

migration of tumor into regional lymph nodes

metastasis and invasion of tumor to distant tissues