# Diagnostics roadmap: stains → gene panels → blood tests that decide treatment

Source: https://onco.cc/roadmaps/diagnostics-roadmap/  
OnCo record `diagnostics-roadmap` (Roadmap). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Cancer diagnosis moved from what a tumour looks like under a microscope to what is driving it, and now to reading it from a blood sample. The next step is tests that tell the doctor what to do, not only what is there.

## Summary

Histopathology and immunohistochemistry remain the foundation of every cancer diagnosis, and the first companion diagnostic (HER2 testing paired with trastuzumab in 1998) set the pattern that every targeted drug since has followed: no test, no drug. Single-gene tests gave way to comprehensive genomic profiling of hundreds of genes, tumour-agnostic biomarkers (mismatch repair deficiency, tumour mutational burden, NTRK fusions), and gene-expression signatures that let most women with early hormone-positive breast cancer skip chemotherapy.

The current shift is from tissue to blood and from description to decision. Circulating tumour DNA now genotypes lung cancer without a biopsy, detects molecular residual disease after surgery months before a scan would, and has changed treatment in randomised trials: DYNAMIC halved adjuvant chemotherapy in stage II colon cancer, SERENA-6 switched endocrine therapy on an ESR1 mutation found in blood, and IMvigor011 produced the first ctDNA-guided drug approval in 2026. Digital pathology is following the same path, with the first AI tests that predict treatment benefit from a routine slide cleared in 2025 and 2026.

What decides the pace is validation rather than invention: prospective evidence that acting on a test improves outcomes, standardisation across laboratories, reimbursement for tests that avoid treatment rather than add it, and data that flows between the sequencer, the slide scanner, the record and the registry.

## Fields

- Kind: Roadmap
- Last checked: 2026-09-10

## Sources

- FDA: list of cleared or approved companion diagnostic devices: https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools
- DYNAMIC trial (NEJM 2022): https://www.nejm.org/doi/full/10.1056/NEJMoa2200075

## Connected records

- drugs: [ArteraAI Breast](https://onco.cc/drugs/artera-ai-breast/), [ArteraAI Prostate](https://onco.cc/drugs/artera-ai-prostate/), [cobas EGFR Mutation Test v2](https://onco.cc/drugs/cobas-egfr-mutation-test/), [FoundationOne CDx / Liquid CDx](https://onco.cc/drugs/foundationone-cdx/), [Guardant Reveal](https://onco.cc/drugs/guardant-reveal/), [Guardant360 CDx](https://onco.cc/drugs/guardant360-cdx/), [HER2 IHC and ISH companion assays (HercepTest, PATHWAY 4B5, HER2 Dual ISH)](https://onco.cc/drugs/her2-testing-assays/), [MammaPrint (70-gene signature)](https://onco.cc/drugs/mammaprint/), [Oncotype DX](https://onco.cc/drugs/oncotype-dx/), [PD-L1 IHC 22C3 pharmDx](https://onco.cc/drugs/dako-pd-l1-22c3-pharmdx/), [Prosigna (PAM50)](https://onco.cc/drugs/prosigna/), [RaDaR](https://onco.cc/drugs/radar-mrd/), [Signatera](https://onco.cc/drugs/signatera/), [Tempus xT CDx](https://onco.cc/drugs/tempus-xt-cdx/), [therascreen companion diagnostic kits (KRAS, EGFR, PIK3CA, FGFR, BRAF)](https://onco.cc/drugs/therascreen-cdx/), [TruSight Oncology Comprehensive](https://onco.cc/drugs/trusight-oncology-comprehensive/)
- terms: [Core needle biopsy and fine-needle aspiration (FNA)](https://onco.cc/terms/core-needle-biopsy/), [FDA laboratory-developed test (LDT) rule](https://onco.cc/terms/fda-ldt-rule/), [Tumour-agnostic (tissue-agnostic) approval](https://onco.cc/terms/tumour-agnostic/)
- ideas: [A national platform trial that every ctDNA-positive patient can join](https://onco.cc/ideas/idea-bio2-national-mrd-platform/), [ctDNA-guided adjuvant therapy as the default in stage II-III colon cancer](https://onco.cc/ideas/idea-ctdna-guided-adjuvant-crc/), [Formally qualify tumour-DNA blood tests as a surrogate endpoint for adjuvant trials](https://onco.cc/ideas/idea-tr2-ctdna-mrd-qualification/), [Make resistance a diagnosis: sequence at every progression and choose the next line from what the tumour became](https://onco.cc/ideas/idea-lung-resistance-directed-sequencing-at-every-progression/), [Pay for residual disease tests only inside a trial or registry](https://onco.cc/ideas/idea-bio2-mrd-coverage-with-evidence/), [Pre-register biomarker validation studies the way trials are registered](https://onco.cc/ideas/idea-tr2-biomarker-study-registry/), [Publish the four numbers the NHS lung cancer pathway does not currently measure: reflex testing rate, genomic turnaround, surgical access and a lung-specific waiting time in every nation](https://onco.cc/ideas/idea-lung-uk-screening-testing-and-access-gaps/), [Test the drug in biomarker-negative patients too, so the biomarker can be validated](https://onco.cc/ideas/idea-tr2-marker-stratified-default/), [Universal tumour and germline sequencing at diagnosis feeding a shared learning system](https://onco.cc/ideas/idea-moon-universal-sequencing-learning-system/)
- roadmaps: [AI in the oncology clinic: from narrow cleared tools to multimodal decision support](https://onco.cc/roadmaps/ai-oncology-clinic/), [ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment](https://onco.cc/roadmaps/ctdna-tests/), [Early detection roadmap: organ screening → blood tests for many cancers](https://onco.cc/roadmaps/early-detection-roadmap/), [Lung cancer roadmap: from Doll and Hill and the naming of tobacco, through the cytotoxic plateau, computed tomography screening, EGFR and ALK, immunotherapy by PD-L1, the perioperative trials and PACIFIC, to DLL3 in small-cell disease and a 2032 registry watch](https://onco.cc/roadmaps/lung-cancer-evidence-roadmap/), [Prostate cancer roadmap: from Huggins and the discovery that a cancer can depend on a hormone, through the PSA epidemic and what it cost, the androgen receptor drugs, the DNA repair subset and PSMA, to a 2032 registry watch](https://onco.cc/roadmaps/prostate-roadmap/), [Trial modernisation roadmap: the randomised trial → platforms and adaptive designs → decentralised, pragmatic and always-on](https://onco.cc/roadmaps/trial-modernisation-roadmap/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/)
- technologies: [Cancer variant knowledgebases and molecular tumour boards](https://onco.cc/technologies/variant-knowledgebases/), [cfDNA fragmentomics](https://onco.cc/technologies/fragmentomics/), [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/), [Comprehensive genomic profiling](https://onco.cc/technologies/cgp/), [Continuous and near-continuous ctDNA monitoring](https://onco.cc/technologies/continuous-ctdna-monitoring/), [Cytogenetics and FISH](https://onco.cc/technologies/cytogenetics-fish/), [Digital pathology & AI](https://onco.cc/technologies/digital-pathology-ai/), [DNA methylation profiling](https://onco.cc/technologies/methylation-profiling/), [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/), [HRD & BRCA testing](https://onco.cc/technologies/hrd-testing/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [Long-read sequencing (PacBio, Oxford Nanopore)](https://onco.cc/technologies/long-read-sequencing/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/), [MSI and mismatch-repair testing](https://onco.cc/technologies/msi-mmr-testing/), [Multidisciplinary tumour boards](https://onco.cc/technologies/multidisciplinary-tumour-board/), [MUSK (Stanford, vision-language pathology)](https://onco.cc/technologies/musk/), [Pathology & radiology foundation models](https://onco.cc/technologies/pathology-foundation-model/), [Proteomics & phosphoproteomics](https://onco.cc/technologies/proteomics/), [Prov-GigaPath (Microsoft, Providence)](https://onco.cc/technologies/prov-gigapath/), [Reference laboratories and companion-diagnostic testing](https://onco.cc/technologies/reference-laboratories/), [RNA sequencing & expression profiling](https://onco.cc/technologies/rna-seq/), [Single-cell & spatial profiling](https://onco.cc/technologies/single-cell-spatial/), [Spatial biology instruments](https://onco.cc/technologies/spatial-biology-instruments/), [Spatial-omics-guided treatment selection](https://onco.cc/technologies/spatial-omics-guided-therapy/), [Tumour mutational burden testing](https://onco.cc/technologies/tmb-testing/), [Virchow / Virchow2 (Paige, MSK)](https://onco.cc/technologies/virchow/), [Whole-exome & whole-genome sequencing](https://onco.cc/technologies/wes-wgs/), [Whole-slide scanners and image management](https://onco.cc/technologies/whole-slide-scanners/)
- trials: [CIRCULATE-Japan (GALAXY / VEGA / ALTAIR)](https://onco.cc/trials/circulate-japan/), [DYNAMIC](https://onco.cc/trials/dynamic/), [IMvigor011](https://onco.cc/trials/imvigor011/), [INSIGHT](https://onco.cc/trials/insight-gist/), [MASAI (Mammography Screening with Artificial Intelligence)](https://onco.cc/trials/masai/), [RxPONDER (SWOG S1007)](https://onco.cc/trials/rxponder/), [SERENA-6](https://onco.cc/trials/serena-6/), [TAILORx](https://onco.cc/trials/tailorx/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [Data silos](https://onco.cc/bottlenecks/b-data-silos/), [Dormant cells and minimal residual disease](https://onco.cc/bottlenecks/b-dormancy-mrd/), [Tumour heterogeneity and clonal evolution](https://onco.cc/bottlenecks/b-tumor-heterogeneity/)

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