Education concepts

Use a concept to answer one question; use a guide to learn toward a goal. These summaries and the glossary definitions are generated from the concept pages. Domain and learner review remain pending where stated on each page.

Biology basics

Concept	In one sentence
Central dogma: from DNA to RNA to protein	For a protein-coding gene, cells transcribe DNA into RNA and translate the RNA into protein.

Breast cancer and pathology

Concept	In one sentence
TNM staging	TNM staging describes the primary tumor, regional lymph nodes and distant metastasis using a cancer-specific classification.
Pathologic complete response (pCR)	Pathologic complete response means no residual invasive cancer in the breast or sampled regional nodes after neoadjuvant treatment.
Residual cancer burden (RCB)	Residual cancer burden combines breast tumor-bed measurements and regional-node findings into a score after neoadjuvant treatment.
Surgical margins	A surgical margin is the edge of removed tissue, examined to determine whether cancer reaches that edge.

Engineering and manufacturing

Concept	In one sentence
LNP (lipid nanoparticle)	A lipid nanoparticle is a formulated lipid carrier that can protect RNA and help deliver it into cells.
mRNA construct anatomy	An mRNA construct combines a protein-coding message with sequence features that influence its translation, stability and processing.

Evidence and statistics

Concept	In one sentence
Clinical actionability	Clinical actionability asks whether a finding supports a specific medical decision in the relevant disease and treatment setting.
Prognostic versus predictive biomarkers	A prognostic biomarker is associated with outcome, while a predictive biomarker identifies differences in the effect of a particular treatment.
Hazard ratio	A hazard ratio compares the event hazards of two specified groups over follow-up.
Kaplan–Meier curves	A Kaplan–Meier curve estimates the probability of remaining free of a defined event over time while accounting for incomplete follow-up.
Survival endpoints	A survival endpoint specifies the starting time and which events count during follow-up.
Lead-time bias	Lead-time bias occurs when earlier detection lengthens measured survival from diagnosis without changing when the outcome occurs.
Positive predictive value and base rates	Positive predictive value is the probability of the defined condition among people with a positive test result.

Immunology

Concept	In one sentence
Antigen-processing machinery	Antigen-processing machinery generates protein fragments and loads them onto display molecules for T-cell inspection.
B2M (beta-2 microglobulin)	Beta-2 microglobulin supports the assembly and stable surface expression of classical human leukocyte antigen class-I complexes.
Cross-presentation	Cross-presentation occurs when a cell displays externally acquired antigen on class-I human leukocyte antigen molecules.
HLA (human leukocyte antigen)	HLA molecules display protein fragments for T-cell recognition.
Neoantigen	A neoantigen is an immune-recognition target arising from a tumor-specific sequence alteration.
T-cell priming and the three-signal model	T-cell priming is the initial activation of a naive T cell by antigen recognition and a supporting signal context.
T-cell states	T-cell states describe changing differentiation and functional programs, rather than simply whether a T cell is present.
TCR (T-cell receptor)	A conventional alpha-beta T-cell receptor recognizes a peptide together with the human leukocyte antigen molecule displaying it.
Innate vs adaptive immunity	Innate immunity uses inherited sensing systems, while adaptive immunity expands cells with diverse antigen-specific receptors.
The immune-cell roster	Immune cells perform different sensing, presentation, killing, antibody-producing and regulatory jobs that depend on their state and location.
Immune escape	Immune escape occurs when cancer cells survive by avoiding recognition, access or effective immune attack.

Measurement and assays

Concept	In one sentence
ctDNA (circulating tumor DNA) units and detection limits	A circulating tumor DNA number is meaningful only with the assay’s measured quantity, units and detection criteria.

Treatment mechanisms

Concept	In one sentence
CAR (chimeric antigen receptor) anatomy	A chimeric antigen receptor connects an external antigen-binding region to internal signaling machinery in an engineered immune cell.

Terminology provides quick definitions, including legacy entries that have not yet become concept pages.