{"entity":{"id":"oncology-pharmacogenomics","kind":"technology","name":"Pharmacogenomic testing before chemotherapy","aka":[],"tldr":"Testing a patient's inherited genes before certain chemotherapies to spot people who cannot break the drug down and would suffer severe, sometimes fatal, side effects.","summary":"Germline variants alter how patients handle several cancer drugs. DPYD variants reduce dihydropyrimidine dehydrogenase and cause severe toxicity with fluorouracil and capecitabine; UGT1A1*28 raises irinotecan toxicity; TPMT and NUDT15 variants make thiopurines dangerous. Pre-treatment DPYD testing is required or recommended across much of Europe and by the NHS, and dose reduction guided by genotype has been shown to cut severe toxicity without loss of efficacy.","status":"established","asOf":"2026-09-04","wikipedia":"https://en.wikipedia.org/wiki/Pharmacogenomics","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Pharmacogenomics"}],"tags":[],"related":[],"cancers":[],"sections":["diagnostics","chemotherapy","supportive-care"],"technologies":[],"targets":[],"drugs":["fluorouracil","capecitabine","irinotecan"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"principle":"Genotype defined variants from blood or saliva and adjust starting doses according to consortium guidelines such as those of the Clinical Pharmacogenetics Implementation Consortium.","strengths":["Prevents severe and fatal toxicity","Cheap, once-per-lifetime test","Guideline-backed dose tables"],"limitations":["Covers only known variants and ancestries unevenly","Turnaround can delay treatment","Uptake outside Europe remains patchy"]},"route":"/technologies/oncology-pharmacogenomics/","neighbours":{"section":[{"id":"chemotherapy","kind":"section","name":"Chemotherapy","route":"/fronts/chemotherapy/"},{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"drug":[{"id":"capecitabine","kind":"drug","name":"Capecitabine","route":"/drugs/capecitabine/"},{"id":"fluorouracil","kind":"drug","name":"Fluorouracil (5-FU)","route":"/drugs/fluorouracil/"},{"id":"irinotecan","kind":"drug","name":"Irinotecan (and liposomal irinotecan)","route":"/drugs/irinotecan/"}]}}