CA19-9

CA19-9 (carbohydrate antigen 19-9 or sialylated Lewis (a) antigen) is a blood test from the tumor marker category. It was discovered in patients with Colon Cancer and Pancreatic Cancer in 1981. Increased levels of CA19-9 are also found in non-malignant conditions, such as Mirizzi’s Syndrome and diseases of the bile duct and liver. The main use of CA19-9 is to determine whether a pancreatic tumor is secreting it; if that is the case, then the levels should fall when the tumor is treated, and they may rise again if the disease recurs.

CA19-9 antigen is highly expressed in Gastrointestinal (gastric, pancreatic, and colonic) Adenocarcinomas and salivary gland Mucoepidermoid Carcinomas. CA19-9 is usually not reactive with breast, kidney, and prostate Carcinomas, but is reactive with sialylated Lea-active pentasaccharide (sialylated lacto-Nfucopentaose II), which is enzymatically synthesized by sialylation of Type 1 carbohydrate chains.

CA 19-9 is a mouse monoclonal antibody derived from cell culture supernatant that is concentrated, dialyzed, filter sterilized and diluted in buffer pH 7.5, containing BSA and sodium azide as a preservative.

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1. Cut and mount 3-4 micron formalin-fixed paraffin-embedded tissues on positive charged slides.
2. Air dry for 2 hours at 58° C.
3. Deparaffinize, dehydrate and rehydrate tissues.
4. Subject tissues to heat epitope retrieval using a suitable retrieval solution such as ImmunoDNA Retriever with Citrate (BSB 0020-BSB 0023) or EDTA (BSB 0030-BSB 0033).
5. Any of three heating methods may be used:
   • Electric Pressure Cooker
     Place standoff rack at base of pressure cooker. Add 1-2 inches of distilled water to the pressure cooker and turn heat to high, and incubate for 15 minutes. Open and immediately transfer slides to room temperature.
   • Water Bath Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a water bath set at 95°-99° C. Incubate for 30-60 minutes.
   • Conventional Steamer Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a Steamer, cover and steam for 30-60 minutes.
6. After heat treatment, transfer slides in ImmunoDNA Retriever with Citrate or EDTA to room temperature and let stand for 15-20 minutes.
7. Wash slides with IHC wash buffer or DI water.
8. Continue IHC staining protocol.