Algorithm
A systematic process consisting of an ordered sequence of steps, each step depending on the outcome of one or more previous steps. In computation, an algorithm is the set of machine instructions used to process information. Algorithms are often represented by flowcharts.

Annotation
Explanatory or extra information associated with a particular biospecimen. This information might include the clinical condition of the patient who donated the biospecimen, collecting and processing procedures, and storage conditions.

Benign Tumor
A noncancerous tumor that may grow but does not invade nearby tissue or spread to other parts of the body.

Biomarkers
Biological substances or features that can be used to indicate normal biological processes, disease processes, or responses to therapy. Biomarkers can be physiological indicators, such as heart rate or blood pressure, or they can be molecules in the tissues, blood, or other body fluids. For example, elevated blood levels of a protein called prostate specific antigen is a molecular biomarker for prostate cancer.

Biomaterials
See Biospecimen

Biobank
See Biorepository

Bioinformatics
The use of mathematics, statistical techniques, and computers to analyze biological data.

Biopsy
The removal and examination of a tissue sample from the living body to determine the existence or cause of a disease. Biopsies are performed by passing a biopsy needle through the skin into the organ in question or by extracting a small piece of the organ during open surgery.

Biorepository
A building, room, or container where biospecimens are stored, either for clinical or research purposes. A biorepository can be a formal organization or an informal collection of materials in a scientist's freezer.

Biospecimen
Any biological material taken from a person for diagnostic or research purposes. Biospecimens can be cellular molecules (such as DNA or proteins), cells, tissues (such as skin, bone, or muscle), organs (such as liver, heart, or kidney), blood, gametes (sperm and ova), embryos, fetal tissue, or waste (such as urine, feces, or nail clippings).

Case Report Form
A form used in clinical trials. Investigators record data on the form that will be used to answer the research questions and determine the safety of the therapy being tested.

Controls
In a clinical study, members of a comparison group who differ in disease experience or treatment from those being studied. If the effects of a disease are being studied, the controls lack the disease. If the effects of a treatment are being studied, the controls are treated with a placebo, or a substance that has no clinical effect.

Cryogenic Freezing (Cryopreservation)
The preservation of cells, tissues, or organs at very low temperatures, typically -80°C (dry ice temperature) or -196°C (the boiling point of liquid nitrogen).

Deletion
In genetics, the loss of any portion of the genetic material on a chromosome. The deletion can involve the loss of a single nucleotide, or DNA "e;letter;"e; part or all of a gene; or a microscopically visible portion of the chromosome, possibly involving multiple genes.

Diagnosis
Identifying a disease by its objective indications (signs), subjective sensations (symptoms), and laboratory findings.

Encrypted
Electronic information, such as in a computer file, that has been converted into a secret code (a system of letters, numbers, or symbols) that people cannot understand or use without an electronic "e;key"e; to decode the information. Encryption may be used to protect medical and genetic information.

Fixative
A fluid, often consisting of a mixture of several reactive chemicals, that is used to prepare tissues and cells for microscopic study. The fixative quickly kills the cells or tissues, hardens them so that they can withstand further processing, and preserves them in a close facsimile of the living state. Information about the cell or tissues molecular state is usually lost. Examples of chemicals used in fixatives include formaldehyde and ethanol.

Formalin
A solution of formaldehyde in water, often used to preserve biological specimens.

Gene
The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Genetics
The study of genes and their effects on the inheritance of specific traits and on other biological processes.

Genome
The full set of genes in an individual.

Institutional Review Board
An official group associated with an institution performing medical research. The group reviews research studies being planned within the institution to safeguard the safety, well-being, and rights of study subjects. The group also ensures that the research is legal and ethical. An institutional review board may consist of scientists, physicians, clergy, and patients.

Machine readable
Data that can be fed directly into a computer without the need for retyping. The term is usually applied to data that have been stored magnetically on disk or tape, but it can also be applied to bar codes or text that can be scanned.

Malignant Tumor
A cancerous tumor that invades surrounding tissues and spreads to other parts of the body.

Molecular Signatures
The coexpression of certain genes in normal or diseased tissue or a microbe. In medicine, the term is usually applied to tumors. The molecular signature of a tumor can be used to describe and classify the tumor. It can also sometimes be used to predict clinical outcomes, including disease progression, response to chemotherapy, and patient survival time.

Mutation
Any permanent change in the genetic material of a cell. In humans, this genetic material is DNA. Mutations may be caused by mistakes during cell division or by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect. Certain mutations may lead to cancer or other diseases.

Oncogene
A gene that contributes to the malignancy of cancer cells.

Oncoprotein
A protein that is coded for by an oncogene and that is involved in tumor cell growth.

Personalized Medicine
The use of molecular analysis methods to better manage a patient's disease or disease predisposition. These methods include testing for variations in genes, gene expression, proteins, and metabolites. Test results are correlated with clinical factors-such as drug response, disease state, and treatment prognosis-and help physicians individualize treatment for each patient.

Protocol
A detailed plan for an experiment, procedure, or test.

Reagent
A substance taking part in a chemical reaction, especially one used to detect, measure, or prepare another substance.

Tissue Microarray
Paraffin block consisting of up to a thousand separate tissue samples of regular size and shape and arranged in an orderly fashion. Sections from this block are cut into 100-500 thin slices, each of which is mounted on a microscope slide and treated for a variety of microscopic analyses.

Transcription
The process by which the DNA sequence in a gene is copied into a molecule called messenger RNA (mRNA). The mRNA leaves the cell nucleus and enters the cytoplasm, where the mRNA's genetic information is used for synthesizing a protein.

Transplantation
The process of removing an organ or tissue from one individual and placing it inside another. Transplantation can also refer to moving a tissue section from one area of a person's body to another area in the same person.

Tumor
An abnormal mass of tissue that possesses no physiological function and arises from preexisting cells through uncontrolled cell division.

Unstructured
Cancer tissue lacking the microscopic structure or organization of normal tissue. Among the traits of cancer tissue that contribute to its unstructured appearance are a large number of dividing cells, variations in cell size and shape, loss of specialized cell features, and a poorly defined tumor boundary.