CA125

Aliases
  • CA-125
  • CA125
  • CA125 ovarian cancer antigen
  • FLJ14303
  • MUC-16
  • MUC16
  • Mucin 16
  • Mucin-16
  • Ovarian cancer-related tumor marker CA125
  • Ovarian carcinoma antigen CA125
  • mucin 16, cell surface associated
Description
From NCBI Gene: This gene encodes a protein that is a member of the mucin family. Mucins are high molecular weight, O-glycosylated proteins that play an important role in forming a protective mucous barrier, and are found on the apical surfaces of the epithelia. The encoded protein is a membrane-tethered mucin that contains an extracellular domain at its amino terminus, a large tandem repeat domain, and a transmembrane domain with a short cytoplasmic domain. The amino terminus is highly glycosylated, while the repeat region contains 156 amino acid repeats unit that are rich in serines, threonines, and prolines. Interspersed within the repeats are Sea urchin sperm protein Enterokinase and Agrin (SEA) modules, leucine-rich repeats and ankyrin (ANK) repeats. These regions together form the ectodomain, and there is a potential cleavage site found near an SEA module close to the transmembrane domain. This protein is thought to play a role in forming a barrier, protecting epithelial cells from pathogens. Products of this gene have been used as a marker for different cancers, with higher expression levels associated with poorer outcomes. [provided by RefSeq, May 2017]
Attributes
QA State
Accepted
Type
Protein
HGNC Name
MUC16
Certifications
  • None
QA State for Breast
Curated

 Non-Public Biomarker

Organ-specific information for this biomarker is currently being annotated or is "under review". Logging in may give you privileges to view additional information. Contact the Informatics Center if you believe you should have access.

Certifications
  • None
QA State for Ovary
Accepted
Organ-Specific Notes

The best known marker for late stage and to a lesser degree early stage ovarian carcinomas - especially of serous and endometrioid histology. Overexpressed in ovarian carcinomas and ovarian low malignant potential (LMP) tumors as compared to the expression in normal ovarian tissue and ovarian adenomas. CA125, an epithelial sialomucin also called MUC16, is a heavily glycosylated protein with relatively high molecular weight and is the only approved marker for monitoring ovarian cancer. Although sialomucins are transmembrane in location, they can be found in serum. Most of the markers in this category have been identified through approaches in which human cancer cells are used as an antigenic stimulus in animals to raise antibodies, which can then efficiently detect the antigen in human serum. CA125 is the best documented and best performing single marker among the epithelial sialomucins. CA125 can be elevated in early pregnancy and with endometriosis, fibroids or infections of the genital tract. These conditions would affect specificity of the test and the possibility of false positive results.

Performance Comment

Of the 28 ovarian cancer biomarkers tested in prediagnostic specimens, from the PLCO, CA125 remains the the single best biomarker for ovarian cancer and has its strongest signal within six months of diagnosis.

Supporting Study Data
Ovarian Cancer Detection by Uterine Lavage DNA and Serum Proteins: A Phase 2 Biomarker Study
Study phase on the ovary: 2

This project investigates the complementarity of tumor DNA (tDNA) in uterine lavage to serum proteins for detection of ovarian cancer and builds on the results from project 1. Since there is no biobank of uterine lavage a prospective study is required. Two hundred patients scheduled for surgery for suspected ovarian cancer will be enrolled at four recruitment sites (50 pts at each site) and blood drawn before anesthesia and uterine lavage obtained before surgery. tDNA will be analyzed at two sequencing sites and serum proteins measured at two immunoassay sites.

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Decision rule: No decision rule specified.
PLCO Ovarian Phase III Validation Study
Study phase on the ovary: 4

see objectives

View Protocol
Decision rule: PMID:21372037
Phase II Validation of a New Panel of Biomarkers for Early Detection of Ovarian Cancer
Study phase on the ovary: 3

While all cancer patients could potentially benefit from earlier detection and prevention, the development of new screening technologies and chemoprevention for epithelial ovarian cancer (EOC) is unique in this regard. EOC is characterized by few early symptoms, presentation at an advanced stage, and poor survival. Presently there is no commercially available test that is diagnostic for either early or advanced stage epithelial ovarian cancer. The most commonly used marker, CA125, identifies a group of cell surface glycoproteins, which have uncertain biological behavior and very limited clinical utility for the detection of early stage disease. In recent years, several approaches have been used in order to develop a test for early detection, including the analysis of serum samples by SELDI-TOF and MALDI-TOF to find proteins or protein fragments of unknown identity that detect the presence/absence of cancer. Unfortunately, at the present time, none of these techniques have been shown to be adequate. Therefore, the development of a test that can detect early stages of the disease could dramatically improve treatment success and long-term survival. We have developed a new blood test based on a different approach: 1) we used known proteins related to cancer biology, 2) we characterized these proteins with several different screening steps using samples obtained from both healthy and cancer patient populations, and 3) validated the results with different techniques. Using split point analysis with four markers, 96 out of 100 EOC patients (96%) were correctly diagnosed with ovarian cancer (including 23 of 24 patients with Stage I/II EOC). In the healthy group, 6 out of 106 individuals were diagnosed incorrectly (5.6%). Working in collaboration with the Early Detection Network (EDRN/NCI/NIH), we performed Phase I discovery study confirming the potential application of this test for early detection of ovarian cancer (Preliminary results). The main objective of this pr

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Decision rule: No decision rule specified.
SPORE/EDRN/PRE-PLCO Ovarian Phase II Validation Study
Study phase on the ovary: 4

see objectives

View Protocol
Decision rule: PMID:21372037
Validation of Early Detection Ovarian Cancer Biomarkers (Team Project)
Study phase on the ovary: 2

Early detection of Ovarian Cancer (OC) is one of the key clinical problems in this disease. We propose a team EDRN project to address the issue of early detection of OC by performing a validation study on candidate protein markers already identified in previous EDRN research or in the literature (e.g. protein products of TCGA identified mutations specific to ovarian cancer). (See appendix for full listing) Biospecimen sources have been identified which include samples obtained at diagnosis and matched controls (Urban, Godwin, Marks, Skates), and longitudinal samples obtained prior to diagnosis (Urban, Skates, Godwin). Bioinformatic filters will be applied to rank the candidates (Diamandis). In order of ranking, candidate proteins for which high quality antibodies are available will be measured by development of ELISAs at JHU (Chan/Zhang) or through NAPPA at DFCI (Anderson/LaBaer), while for other candidates mass spectrometry based selective reaction monitoring (SRM) assays will be developed at PNNL (Rodland). Three milestones are defined. The first two milestones are to assemble the necessary specimens and to develop the qualifying assay(s). The final milestone is to estimate the markers’ sensitivity one year prior to diagnosis at a given high specificity.

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Decision rule: No decision rule specified.
Ovary-Specific Protocols
  • No organ-level protocols specified for ovary.
Ovary-Specific Publications
  • No organ-level publications were listed for ovary.
Ovary-Specific Resources
  • No organ-level resources were given for ovary.
Certifications
  • None
QA State for Pancreas
Under Review

 Non-Public Biomarker

Organ-specific information for this biomarker is currently being annotated or is "under review". Logging in may give you privileges to view additional information. Contact the Informatics Center if you believe you should have access.