NucLexNuclear Medicine Lexicon and Theranostics Ontology
Stage W0: private living prototype12 of 30 manuscripts drafted, 0 reviewed; 50 lexicon entries in draftWhat each later stage would need to show

NucLex for innovators

Molecular targeting

That a cell expresses a molecule is one fact. That a drug reaches it, binds it, stays, and does not bind elsewhere are four more.

MonographBriefNX-M16Proposed length 2,500 to 5,000 words

Writing brief. This monograph has been assigned but the manuscript is not yet written or approved. What follows is the commissioning brief: its question, outline, evidence instructions, and review requirements.

Central question

What must be known about a target?

Reader promise

The reader will be able to separate five questions often collapsed into "is this a good target": which cells express the molecule, where it sits, whether an agent can reach it, how strongly and how long it binds, and what else it binds, and will know what evidence answers each.

Required development

  1. Cell type and expression. Define Target expression as a measurable property of a Cell type under stated conditions; distinguish transcript from protein, tumor from normal tissue, and population average from single-patient measurement.
  2. Location. Explain Subcellular location (surface, intracellular, secreted, shed) and why it changes which agents can engage the target and whether internalization matters for a radionuclide's effect.
  3. Accessibility. Treat delivery as a separate question: vascular supply, interstitial pressure, barrier tissues, and the agent's size and charge. Connect to Biodistribution and pharmacokinetics.
  4. Affinity and residence. Define Binding affinity and residence time as measured quantities with units and conditions; explain that an in vitro constant is a property of an assay as well as of a molecule.
  5. Off-target interaction. Define Off-target binding and distinguish it from on-target binding in normal tissue; show with a labelled conceptual diagram (no measured values) how intended and unintended binding raise separate questions. Connect to Molecules as language without converting the analogy into a parameter.
  6. Draw the conclusion the review gate demands. Show, in a synthetic example, a target that is highly expressed and still a poor therapeutic target because one of the other questions has an unfavourable answer.

Evidence and review

Evidence to obtain: UniProt documentation on subcellular location annotation and evidence codes; Human Protein Atlas documentation on expression evidence and reliability scores; a standard receptor pharmacology reference for affinity, dissociation constant, and residence time with assay conditions; peer-reviewed reviews of radioligand target selection in nuclear oncology. No measured affinity, expression, or selectivity value may appear unless quoted from a cited source with units and conditions.

Review concern: the manuscript must not state or imply that any named target predicts therapeutic benefit, and must not present an analogy-derived quantity as a model parameter.

Molecular target, Target expression, Subcellular location, Cell type, Binding affinity, Off-target binding, Ligand, Biomarker, Biodistribution and pharmacokinetics, Radiopharmaceutical identity, Precision nuclear oncology, Molecules as language.

Review requirements

Source check of every definition against the cited database documentation or pharmacology reference. Domain review by a molecular biologist or radiochemist with target validation experience and a nuclear medicine physician. Editorial check that the five questions are answered separately and the review gate's conclusion is explicit.

Review gate for this monograph

Expression alone does not establish therapeutic response.

The assignment exists. The manuscript has not been written or approved.