failure-free survival: the time from enrollment onto a clinical trial or from the start of treatment to disease progression, recurrence, death, or other prespecified event.
FAK (focal adhesion kinase): a protein tyrosine kinase recruited at focal adhesions, which are sites at cell membranes where cytoskeletal elements interact with extracellular matrix proteins. Cell migration and differentiation are initiated at these sites. Typically, FAKs are activated by Src.
false-discovery proportion: one of the several statistical measures to quantify the chance of false discovery in multiple hypothesis testing. Other methods include calculating false discovery
rates or familywise error rates.
false-discovery rate: a statistical method used to correct for multiple comparisons. Instead of using
significance levels, false-discovery rate allows for a certain fraction (defined by a q value) of the tests declared positive by the statistics to be truly negative. The false-discovery rate of a set of statistical tests is the expected percentage of false positives in the set of tests. There are several algorithms available for selecting positive genes while controlling the false-discovery rate.
false-discovery rate (FDR): a statistical method used to correct for multiple comparisons. Instead of using
significance levels, false-discovery rate allows for a certain fraction (defined by a q value) of the tests declared positive by the statistics to be truly negative.
The false-discovery rate of a set of statistical tests is the expected percentage of false positives in the set of tests. There are several algorithms available for selecting positive genes while controlling the false-discovery rate.
farnesylation: see FT (farnesyltransferase).
Fas: a transmembrane death receptor activated by the Fas ligand, leading to the formation of death-related signaling complexes at the membrane.
Fas ligand: ligand for the death receptor Fas. See Fas.
FBL: gene encoding for fibrillarin, which is a component of a nucleolar small nuclear ribonucleoprotein particle thought to participate in the first step in processing preribosomal RNA. In humans, fibrillarin is associated with the U3, U8, and U13 small nuclear RNAs.
FBXO5: gene encoding a member of the F-box protein family. These proteins are substrate-targeting subunits of the ubiquitin-ligase complex.
Fcγ receptors: receptors for immunoglobulin G. Fcγ receptors are expressed on leukocytes and comprise three distinct classes:
FcγRI, FcγRII, and FcγRIII. In humans, the latter two classes can be further divided into FcγRIIa and FcγRIIb and FcγRIIIa and FcγRIIIb.
feature selection: determining the set of genes to include in the classifier on the basis of their likelihood to be differentially expressed in tumors of different stages or in response to therapy.
febrile neutropenia: symptoms include fever and a decrease in
the number of neutrophils in the blood. A low neutrophil count increases the risk of infection.
FGF (fibroblast growth factor): part of the FGF family of proteins, which are involved in proliferation and differentiation of several cell types. It binds to receptors belonging to the tyrosine kinase family.
FGFR (fibroblast growth factor receptor): a family of tyrosine kinase receptors that has four members, FGFR1-4. Like other tyrosine kinase receptors, intracellular signaling follows receptor dimerization in response to ligand binding. This leads to autophosphorylation of the tyrosine molecules in the intracellular tyrosine kinase region of the receptor.
FGFR2: important in embryogenesis. Defects in FGFR2 cause several craniosynostosis syndromes such as Apert syndrome, Crouzon syndrome, Jackson-Weiss syndrome, and Pfeiffer syndrome.
FGFR3: gene that might mediate an inhibitory signal, restraining growth of chondrocytes during ossification. FGFR3 has been shown to cooperate with FGFR4 in lung development.
FGFR4: shows strong binding to acidic FGF, bFGF, FGF4, FGF6, FGF8, and FGF9. FGFR3 and FGFR4 have been shown to cooperate in lung development. FGF4 is involved in the development of endoderm derivatives and in skeletal muscle formation and also plays a role in the cascade of molecular events leading to terminal muscle differentiation.
FIGO histologic grading: a grading system for endometrial carcinoma defined by the International Federation of Gynecology and Obstetrics (FIGO). FIGO histologic grading is a three-grade system primarily defined by tumor architecture and modified in the presence of notable nuclear atypia. FIGO grade has prognostic value.
FIGO staging: a tumor staging system established and revised by the International Federation of Gynecology and Obstetrics (FIGO) that takes into account the postoperative histopathologic evaluation of the specimen. The FIGO stage classification has prognostic value.
FIP1L1-PDGFRA: a constitutively activated tyrosine kinase that transforms hematopoietic cells. The FIP1L1-PDGFRA fusion protein is expressed as a result of a chromosomal abnormality identified in patients with the hypereosinophilic syndrome. The abnormality occurs as a consequence of the fusion of FIP1L1 (coding for Fip1-like 1 protein) gene to the PDGFRA (coding for PDGFRA) gene and is generated by an interstitial deletion on chromosome 4q12.
first-degree family history: the record of a recurring medical condition occurring in family members who share about 50% of their genes, including parents, offspring, and siblings.
FISH (fluorescent in situ hybridization): in situ hydridization is a sensitive method generally used to detect specific gene sequences in tissue sections or cell preparations by hybridizing the complementary strand of a nucleotide probe to the sequence of interest. FISH uses a fluorescent probe to increase the sensitivity of in situ hybridization.
FK506: also called tacrolimus. FK506 is a hydrophobic macrolide lactone and functions as a potent immunosuppressant. FK506 forms a complex with the rapamycin-binding protein and inhibits mammalian target of rapamycin activity.
FKBP12: see rapamycin-binding protein.
FLT1: see vascular endothelial growth factor receptor (VEGFR).
FLT3: a member of the family of receptor tyrosine kinases, which include c-kit and fms. FLT3 is expressed on hematopoietic stem cells and plays a role in both differentiation and proliferation. It has been implicated in the pathogenesis of acute myelogenous leukemia.
FLT3L: a growth factor that stimulates the proliferation of hematopoietic cells by binding to and activating distinct FLT3 tyrosine kinase receptors on cells. see FLT3.
[18F]fluorodeoxyglucose-positron emission tomography: positron emission tomography with the glucose analog [18F]fluorodeoxyglucose.
forkhead: a family of transcription factors that contains no known motifs characterized in other transcription factors. It has a distinct DNA-binding motif that binds to B-DNA. Although known to be involved in early developmental decisions, the forkhead family of transcription factors has also been implicated in inhibiting cell-cycle progression at the G1/S phase of the cell cycle.
formalin-fixed, paraffin-embedded tissue: the standard for tissue preparation
in anatomic pathology. The processing of tissue historically has included cutting into thin (5-mm) sections, then placing a cassette for fixation in formalin in a tissue processor followed by infusion of paraffin and embedding on the block for subsequent sectioning for histologic evaluation or immunohistochemistry.
Fos: a component of AP (activator protein)-1. Fos activates transcription when it heterodimerizes with its natural partner, jun.
FoxO3A: a member of the forkhead group of transcriptional factors.
FoxP3: the forkhead transcriptional factor that is specifically expressed in CD4+CD25+ regulator T cells. See forkhead.
frame shift: the addition or deletion in one or more bases. This kind of deletion alters the reading frame of the gene from the point of deletion forward.
framework regions (FR): four regions (FR1-4) in the rearranged IgH gene that connect the complementary determining regions
(CDR1-3). The CDR1-3 regions are the primary determinants of antigen binding
of the antibody.
FRAP1: he HUGO Gene Nomenclature Committee (HGNC: http://www.genenames.org/)–approved official gene symbol for FK506 binding protein 12-rapamycin associated protein 1 or so-called mammalian target of rapamycin.
FRZB1: gene encoding for the frizzled-related protein 1, which functions as negative modulator of Wnt signaling through direct interaction with Wnts. Soluble frizzled-related proteins (SFRPs) have a role in regulating cell growth and differentiation in specific cell types. Methylation silencing of SFRPs may be one of the important mechanisms of aberrant Wnt signaling activation in multiple myeloma; FRZB1 is thought to play a role in the transition from MGUS (monoclonal gammopathy of undetermined significance) to multiple myeloma.
FT (farnesyltransferase): enzymatic activity that allows for the covalent addition of a farnesyl group (a 15-carbon moiety) to a cysteine residue in a protein. Farnesylation is known to occur in proteins with a variety of cellular functions. See Pro-Ras and CENP-E, -F.
FT inhibitors: small molecules that inhibit the transfer of farnesyl groups to cellular substrates, thus impairing signal transduction.
Functional Assessment of Cancer Therapy-Prostate (FACT-P): consists of the Functional Assessment of Cancer Therapy (FACT) general (FACT-G) questionnaire plus a prostate-specific subscale. The FACT-G is composed of seven questions related to physical well-being, seven questions related to social well-being, six questions related to emotional well-being, and seven questions related to functional well-being. Subscale scores range from 0 to 24 (emotional) or 0 to 28 (functional, social, and physical). A total FACT-G score is computed as the sum of the individual subscales; the overall score ranges from 0 to 108. The prostate subscale comprises 12 questions that are specific to men with prostate cancer. It ranges from 0 to 48. The FACT-P score is the sum of FACT-G and the prostate-specific subscale with a range from 0 to 156. Higher scores indicate better quality of life.
FVIII-RA (factor VIII-related antigen): also called von Willebrand factor. FVIII-RA has been used to identify early megakaryoblasts in myelopropliferative disorders and differentiate megakaryocytes from other multinucleated cells. A highly specific endothelial cell marker, FVIII-RA may also be used to demonstrate an abnormal vascular network, which is often seen in myeloproliferative and myelodysplastic diseases. In conjunction with CD34, FVIII-RA is used to mark endothelial cells that originate in tumors. Because its expression is sufficiently restricted to endothelial cells, it is a specific marker of these cells (with the exception of megakaryocytes).
Fyn kinase: a member of the Src family of nonreceptor tyrosine kinases. Fyn is localized at growth cones and postsynaptic membranes of neurons. Fyn expression is seen in several regions of the brain, including the olfactory bulb, cerebellum, hippocampus, and limbic system. Fyn phosphorylates several receptors (eg, the NMDA receptor) and modulates their functions. Fyn is also implicated in the regulation of protein expression in activated T cells, galectin being among one of the proteins regulated.