Normal upper limit of CA – 125 is ?
Correct Answer: 25 U/ ml
Description: Ans. is `a' i.e., 25 U/ ml The normal value is less than 35 U/mL 1) Carcinoembryonic antigen (CEA) It is a glycoprotein produced by fetal gut, pancreas and liver. It is used as tumor marker for colorectal cancer (major use), lung cancer, breast cancer and ovarian cancer. It is also increased in non-neoplastic conditions like alcoholic cirrhosis, hepatitis, IBD (CD, UC), smoking and pancreatitis. In colorectal cancer it is used for screening; response and follow up after surgery (CEA should diseapper in 6 weeks after resection), prognosis (higher levels suggests high tumor burden) and to see recurrence on follow up. CEA antigen has no correlation with hepatic metastasis. CEA lacks sensitivity as well as specificity, hence cannot be used to confirm the diagnosis. 2) Alpha-feto protein (AFP) It is a glycoprotein synthesized normally early in fetal life by yolk sac, fetal liver and fetal GIT. It is structurally and genetically related to albumin. AFP is raised in liver cancer (hepatocellular carcinoma), lung carcinoma, pancreatic carcinoma, colon carcinoma, and non-seminoma germ cell tumor of testis/ovary (yolk sac tumor/endodermal sinus tumor, embryonal carcinoma, teratoma). AFP is also raised in some non-neoplastic conditions like cirrhosis, hepatitis, and pregnancy. 3) Human chorionic gonadotropin (HCG) It is a placental hormone synthesized by syncytiotrophoblasts. It is glycoprotein with two subunits (dimer) : a-subunit and /3-subunit. But only the P subunit of HCG is typically measured as a tumour marker because of specificity of the 13 subunit. The i3 subunit of HCG has unique sequences that are not shared with other human glycoprotein hormones. It is detected by radioimmunoassay using antibodies to the 13 chain. a-HCG is not used as tumour marker because a unit of the FSH, LH and TSH are identical. So there can be cross reactivity between a subunits of these hormone. That is why in case of testicular tumours the patients also undergo simultaneous assay of LH to be ceain that the marker detected is 13 HCG. HCG (13-HCG) is raised in gestational trophoblastic disease (hydatidiform moles), gonadal germ cell tumor (embryonal carcinoma, choriocarcinoma), and pregnancy. 4) CA-125 Most impoant cancer with elevated CA-125 is epithelial ovarian cancer. CA-125 is also elevated in cancers of endometrium, cervix, fallopian tubes, pancreas, breast, lung and colon. Non-neoplastic conditions causing elevation of CA-125 are pregnancy, mensturation, endometriosis, PID, abdominal TB, peritonitis and uterine fibroid. Tumor markers for testicular/ovarian tumor AFP (alpha-feto protein) : Teratoma, Yolk sac tumor (endodermal sinus tumor), embryonal carcinoma. HCG (human chorionic gonadotrophin): Choriocarcinoma, embryonal carcinoma. a,-antitrypsin : Yolk sac tumor (endodermal sinus tumor). Placental alkaline phosphatase : Seminoma. Other : Placental lactogen, LDH.
Category:
Pathology
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