WEEK 9.pdf

TUMOR MARKERS 9 TUMOR MARKERS A tumor marker is a substance present in or produced by a tumor (benign or malignant) or by the tumor's host in response to the tumor's presence Can be used to differentiate a tumor from normal tissue To determine the presence of a tumor based on measurement in the bloo...

TUMOR MARKERS 9 TUMOR MARKERS A tumor marker is a substance present in or produced by a tumor (benign or malignant) or by the tumor's host in response to the tumor's presence Can be used to differentiate a tumor from normal tissue To determine the presence of a tumor based on measurement in the blood or secretions and that can be detected in various body fluids and on the surface of cancer cells. A good tumor marker should.. 1. It should be highly sensitive 2. It should be highly specific 3. 100% accuracy in differentiating between healthy individuals and tumor patients. 4. Should be able to differentiate between neoplastic and non-neoplastic disease and show positive correlation with tumor volume and extent. 5. It should predict early recurrence and have prognostic value. 6. It should be easily assayable and be able to indicate all changes in cancer patients receiving treatment. CLASSIFICATION Enzymes or isoenzymes ALP, PAP Hormones calcitonin, bHcg. Oncofetal antigens AFP, CEA Carbohydrate Epitopes CA 15-3, CA 19-9,CA125 Receptors Estrogen, progesterone Serum and tissue proteins beta-2 microglobulin, monoclonal immunoglobulin, glial fibrillary acidic protein (GFAP), protein S-100 Other biomolecules polyamines POTENTIAL USES Screening in general population Differential diagnosis of symptomatic patients Clinical staging of cancer Estimating tumor volume As a prognostic indicator for disease progression Evaluating the success of treatment Detecting the recurrence of cancer Monitoring reponse to therapy ENZYMES 1. Alkaline Phosphatase (ALP) primary or secondary liver cancer, metastatic cancer with bone or liver involvement. 2. Prostatic acid phosphatase (PAP) prostate cancer Increased PAP activity may be seen in osteogenic sarcoma, multiple myeloma and bone metastasis of other cancers and in some benign conditions such as osteoporosis and hyperparathyroidism. 3. Prostate Specific Antigen (PSA) much more specific for screening or for detection early prostate cancer. HORMONES 1. Calcitonin medullary thyroid cancer 2. Human Chorionic Gonadotropin (hCG) tumors of placenta, gestational trophoblastic disease and some tumors of testes and ovary. ONCOFETAL ANTIGENS 1. a-fetoprotein (AFP) hepatocellular and germ cell carcinoma 2. carcinoembryonic antigen (CEA) colorectal, gastrointestinal, lung and breast carcinoma. CARBOHYDRATE MARKERS 1. CA 15-3 breast carcinoma may also be present in pancreatic, lung, ovarian, colorectal and liver cancer and in some benign breast and liver diseases. 2. CA 125 ovarian and endometrial carcinomas, elevates in pancreatic, lung, breast, colorectal and gastrointestinal cancer, and in benign conditions such as cirrhosis, hepatitis, endometriosis, pericarditis and early pregnancy 3. CA19-9 colorectal and pancreatic carcinoma, elevated levels seen in hepatobiliary, gastric, hepatocellular and breast cancer and in benign conditions such as pancreatitis and benign gastrointestinal diseases. RECEPTOR MARKERS Estrogen and progesterone receptors are used in breast cancer as indicators for hormonal therapy. Patients with positive estrogen and progesterone receptors tend to respond to hormonal treatment. PROTEIN MARKERS 1. ß2-macroglobulin multiple myeloma, Hodgkin lymphoma, also increases in chronic inflammation and viral hepatitis. 2. Ferritin Ferritin is a marker for Hodgkin lymphoma, leukemia, liver, lung and breast cancer. 3. Thyroglobulin It is a useful marker for detection of differentiated thyroid cancer. PROTEIN MARKERS 1. ß2-macroglobulin multiple myeloma, Hodgkin lymphoma, also increases in chronic inflammation and viral hepatitis. 2. Ferritin Ferritin is a marker for Hodgkin lymphoma, leukemia, liver, lung and breast cancer. 3. Thyroglobulin It is a useful marker for detection of differentiated thyroid cancer. 4. Immunoglobulin Bence-Jones protein is a free monoclonal immunoglobulin light chain in the urine and it is a reliable marker for multiple myeloma. GYNECOLOGIC MARKERS 1. CA 125 Proven to be a useful first-generation marker for monitoring ovarian cancer and triaging patients with pelvic masses, despite limitations in sensitivity and specificity. Marked elevations (>1500 U/mL) are generally seen with ovarian cancer. Early detection of ovarian cancer through the measurement of CA-125, usually in combination with other modalities (eg, bimanual pelvic examination, transvaginal ultrasonography), is the most promising application of this tumor marker, permitting effective triage of patients for primary surgery. 2. Beta Human Chorionic Gonadotropin (BHCG) Produced by syncytiotrophoblast of placenta To maintain progesterone production by the corpus luteum during early pregnancy. hCG can be detected as early as one week after conception. Seminomatous germ cell tumours of testis (approx. 20%). 3. ALPHA FETOPROTEIN AFP is a 70 kDa glycoprotein homologous to albumin. fetal serum protein synthesized by the liver, yolk sac, and gastrointestinal tract. AFP is a major component of fetal plasma, reaching a peak concentration of 3 mg/mL at 12 weeks of gestation. Following birth, AFP rapidly clears from the circulation, because its half-life is 3.5 days. AFP concentration in adult serum is less than 20 ng/mL. Malignancies with elevated levels: Non-seminomatous germ cell tumours (NSGCT) of testis, ovary and other sites. Hepatocellular carcinoma (HCC) Hepatoblastoma