Alpha feto-protein (AFP)

Stains
Alpha feto-protein (AFP)

Author: Nat Pernick, M.D. (see Authors page)

Revised: 16 October 2015, last major update December 2011

Copyright: (c) 2003-2015, PathologyOutlines.com, Inc.

PubMed Search: alpha feto protein

Table of Contents

Cite this page: Alpha feto-protein (AFP). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainsafp.html. Accessed July 12th, 2017.

Definition / general

Major plasma protein of early fetus; present in fetal gut, liver and yolk sac (Wikipedia)
Serum levels may be elevated if severe hypothyroidism (J Pediatr Endocrinol Metab 2012;25:761)

Uses by pathologists

Serum marker:
- Elevated in maternal serum or amniotic fluid ( > 2.5 multiples of median at a specified gestational age) if fetal developmental anomalies
- Serum tumor marker elevated in patients with hepatoblastoma (eMedicine), hepatocellular carcinoma, hepatoid adenocarcinoma, testicular cancer (other than pure seminoma) and yolk sac tumor, but not in intrahepatic cholangiocarcinoma (Am Surg 2010;76:1210)
- Preoperative levels are prognostic for hepatocellular carcinoma (World J Surg Oncol 2013;11:212)

Immunostain:
- Somewhat sensitive and specific for hepatocellular carcinoma, hepatoid adenocarcinoma, germ cell tumors and particularly yolk sac tumor

Microscopic (histologic) images

Images hosted on Pathout server:

Dysgerminoma - ovary (negative staining)

Liver: HCC

Images hosted on other servers:

Hepatoid adenocarcinoma: gallbladder, lung, ovary, skull base, stomach

Liver: adult hepatic blastoma (fig B)

Yolk sac tumors: urachus, testis

Yolk sac tumor arising in mature teratoma of liver

Positive staining - normal

Early fetal gut, hepatocytes and yolk sac

Positive staining - disease

Various sites: embryonal carcinoma, some extrahepatic carcinomas (Acta Cytol 2003;47:799), hepatoid adenocarcinoma (J Clin Pathol 1996;49:420, Int J Gynecol Cancer 2007;17:1150, Mod Pathol 2014;27:535), teratomas (some), yolk sac tumor
Liver: hepatoblastoma, hepatocellular carcinoma (60%, Mod Pathol 1997;10:686, Am J Surg Pathol 2002;26:978), infantile hemangioendothelioma (rare, Hum Pathol 2010;41:7633)
Ovary: some Sertoli-Leydig tumors (in hepatoid areas), yolk sac tumors (strong)
Pancreas: acinar cell carcinoma (some, Anticancer Res 2005;25:1671), pancreatoblastoma (up to 68%, JOP 2007;8:55)

Negative staining

Hepatocellular carcinoma-diffuse cirrhosis-like variant (Am J Surg Pathol 2010;34:935)
Cholangiocarcinoma, hepatocellular adenoma and seminoma