Ans. B. CA 19-9. (Ref. H - 17th / pg. 483)Best tumor marker for pancreatic cancer is CA 19-9.CA 19-9 as a Marker for Pancreatic Cancer# CA 19-9 is not recommended for use as a screening test for pancreatic cancer. The use of CA19-9 testing alone is not recommended for use in determining operability or the results of operability in pancreatic cancer.# CA19-9 determinations by themselves cannot provide definitive evidence of disease recurrence without seeking confirmation with imaging studies for clinical findings and/or biopsy.# Present data are insufficient to recommend the routine use of serum CA19-9 levels alone for monitoring response to Rx. However, CA19- 9 can be measured at the start of Rx for locally advanced metastatic disease and every one to three months during active Rx.Tumor markersAlkaline phosphataseMetastases to bone, liver, Paget disease of bone, seminoma (placental ALP).A-fetoproteinNormally made by fetus. Hepatocellular carcinoma, hepatoblastoma, yolk sac (endodermal sinus) tumor, testicular cancer, mixed germ cell tumor (co-secreted with p-hCG).b-hCGHydatidiform moles and Choriocarcinomas (Gestational trophoblastic disease), testicular cancer.CA-15-3/CA-27-29Breast cancer.CA-19-9Pancreatic adenocarcinoma.CA-125Ovarian cancer.CalcitoninMedullary thyroid carcinoma.CEACarcinoEmbryonic Antigen. Very nonspecific but produced by ? 70% of colorectal and pancreatic cancers; also produced by gastric, breast, and medullary thyroid carcinomas.PSAProstate-specific antigen. Used to follow prostate adenocarcinoma. Can also be elevated in BPH and prostatitis. Questionable risk/benefit for screening.S-100Neural crest origin (e.g., melanomas, neural tumors, schwannomas, Langerhans cell histiocytosis).TRAPTartrate-Resistant Acid Phosphatase (TRAP). Hairy cell leukemia--a B-cell neoplasm.GI Tumor Markers (New)# Thymidine Synthase (TS), Dihydropyrimidine Dehydrogenase (DPD), and Thymidine Phosphorylase (TP) as Markers for Colorectal Cancer. TS, DPD, and TP are tissue markers that have been used to predict response to Rx of established carcinomas and thus are not useful for screening.# Microsatellite Instability (MSI) as a Marker in Colorectal Cancer. MSI ascertained by PCR is not recommended at this time to determine the prognosis of operable colorectal cancer nor to predict the effectiveness of 5-FU adjuvant chemotherapy.# 18q-LOH/DCC as Markers for Colorectal Cancer# Assaying for loss of heterozygosity (LOH) on the long arm of chromosome 18 (18q) or DCC protein determination by immunohistochemistry should not be used to determine the prognosis of operable colorectal cancer, nor to predict response to therapy