# Histopathology & immunohistochemistry

Source: https://onco.cc/technologies/histopathology-ihc/  
OnCo record `histopathology-ihc` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Histopathology means looking at cancer cells under a microscope, and immunohistochemistry stains them for specific proteins. Together they are still the foundation of every diagnosis.

## Summary

H&E morphology assigns histologic type and grade; IHC panels define lineage and biomarkers (ER, PR, HER2, Ki-67, PD-L1, ALK, MMR proteins). HER2 IHC scoring now matters at the low end (HER2-low, HER2-ultralow) because of T-DXd. Tumour-infiltrating lymphocyte (TIL) scoring on H&E is becoming a stratification tool in TNBC.

## Fields

- Kind: Technology
- Status: standard-of-care
- Last checked: 2026-09-04
- Principle: Formalin-fixed paraffin-embedded tissue sectioned, stained, and interpreted by a pathologist; antibody-based chromogenic detection of proteins.
- Strengths: Cheap, fast, universal; Companion diagnostic for most targeted drugs
- Limitations: Subjective scoring; Single-site sampling misses heterogeneity

## Notes

- Colorectal cancer: three of the disease's decisions are made on a stain. Four-protein mismatch repair immunohistochemistry on every tumour selects immunotherapy and finds Lynch syndrome; HER2 immunohistochemistry read against the colorectal-specific more-than-50% rule selects HER2-directed therapy (Valtorta 2015); and digital CD3 and CD8 counting in the tumour and invasive margin gives a prognostic Immunoscore independent of stage and microsatellite status (Pages 2018).
- Lung cancer: three of the disease's decisions rest on a stain and they differ in how trustworthy they are. PD-L1 tumour-cell scoring is reproducible between pathologists (intraclass correlation 0.86 to 0.93) and comparable across the 22C3, 28-8 and SP263 assays, while immune-cell scoring is not (0.18 to 0.19) and SP142 reads systematically lower than the rest (Tsao 2018, Rimm 2017). Immunohistochemistry is an acceptable screen for ALK and ROS1 and is explicitly not acceptable for EGFR (Lindeman 2018). And in small-cell disease the transcriptional subtypes can be read with four antibodies, although 37% of tumours express two of the markers at once (Baine 2020).
- Lymphoma: more of this diagnosis rests on a stain than in any solid tumour. A B-cell panel runs CD20, CD79a, PAX5, CD10, BCL6, MUM1, BCL2, MYC, cyclin D1, SOX11 and Ki-67; a T-cell panel runs CD2, CD3, CD4, CD5, CD7, CD8, CD30, ALK, PD-1, CXCL13 and ICOS; a Hodgkin panel runs CD30, CD15, PAX5, CD20 and EBER. The Hans algorithm, three of those stains read in a fixed order, is how cell of origin is reported in most laboratories (Hans 2004). Two failure modes recur: a core needle sample gives cells but not architecture, which is the commonest reason a lymphoma diagnosis has to be repeated, and in classical Hodgkin lymphoma the malignant cells are a small minority of the tissue, so a small sample can miss them altogether (Kuppers 2009).

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Immunohistochemistry
- Wikipedia: https://en.wikipedia.org/wiki/Immunohistochemistry
- Hans et al., Blood 2004: the CD10, BCL6 and MUM1 immunohistochemistry algorithm on 152 cases: https://doi.org/10.1182/blood-2003-05-1545
- Kuppers, Nat Rev Cancer 2009: the biology of Hodgkin's lymphoma: https://doi.org/10.1038/nrc2542

## Connected records

- cancers: [Adenoma-like adenocarcinoma of the colon and rectum](https://onco.cc/cancers/colorectal-adenoma-like-adenocarcinoma/), [Adenosquamous carcinoma of the pancreas](https://onco.cc/cancers/pancreatic-adenosquamous-carcinoma/), [Adult T-cell leukaemia/lymphoma](https://onco.cc/cancers/adult-t-cell-leukaemia-lymphoma/), [Advanced systemic mastocytosis (aggressive SM, SM with an associated haematological neoplasm, mast cell leukaemia)](https://onco.cc/cancers/advanced-systemic-mastocytosis/), [ALK-negative anaplastic large cell lymphoma](https://onco.cc/cancers/alk-negative-anaplastic-large-cell-lymphoma/), [ALK-positive anaplastic large cell lymphoma](https://onco.cc/cancers/alk-positive-anaplastic-large-cell-lymphoma/), [Bowen's disease (squamous cell carcinoma in situ)](https://onco.cc/cancers/bowens-disease/), [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Breast implant-associated anaplastic large cell lymphoma](https://onco.cc/cancers/breast-implant-associated-alcl/), [Burkitt lymphoma](https://onco.cc/cancers/burkitt-lymphoma/), [Cancer of unknown primary (CUP)](https://onco.cc/cancers/cancer-of-unknown-primary/), [Cancer of unknown primary, favourable subsets](https://onco.cc/cancers/cup-favourable-subsets/), [Cancer of unknown primary, unfavourable (adenocarcinoma and poorly differentiated carcinoma)](https://onco.cc/cancers/cup-unfavourable/), [Colloid (mucinous non-cystic) carcinoma of the pancreas](https://onco.cc/cancers/pancreatic-colloid-carcinoma/), [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)](https://onco.cc/cancers/cutaneous-t-cell-lymphoma/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Ductal adenocarcinoma of the prostate](https://onco.cc/cancers/prostate-ductal-adenocarcinoma/), [Early-onset colorectal cancer (under 50)](https://onco.cc/cancers/early-onset-colorectal/), [EBV-positive diffuse large B-cell lymphoma](https://onco.cc/cancers/ebv-positive-dlbcl/), [Endometrial cancer](https://onco.cc/cancers/endometrial/), [Enteropathy-associated T-cell lymphoma](https://onco.cc/cancers/enteropathy-associated-t-cell-lymphoma/), [Esthesioneuroblastoma (olfactory neuroblastoma)](https://onco.cc/cancers/esthesioneuroblastoma/), [Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)](https://onco.cc/cancers/malt-lymphoma/), [Extranodal NK/T-cell lymphoma](https://onco.cc/cancers/extranodal-nk-t-cell-lymphoma/), [Familial adenomatous polyposis-associated colorectal cancer](https://onco.cc/cancers/fap-associated-colorectal-cancer/), [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/), [Gastric MALT lymphoma](https://onco.cc/cancers/gastric-malt-lymphoma/), [Goblet cell adenocarcinoma of the appendix](https://onco.cc/cancers/goblet-cell-adenocarcinoma/), [HER2-amplified colorectal cancer](https://onco.cc/cancers/her2-amplified-colorectal/), [High-grade B-cell lymphoma with MYC and BCL2 rearrangements (double-hit lymphoma)](https://onco.cc/cancers/high-grade-b-cell-lymphoma-myc-bcl2/), [Hodgkin lymphoma](https://onco.cc/cancers/hodgkin-lymphoma/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Indolent and smouldering systemic mastocytosis](https://onco.cc/cancers/indolent-systemic-mastocytosis/), [Inflammatory breast cancer](https://onco.cc/cancers/inflammatory-breast-cancer/), [Invasive carcinoma arising in an intraductal papillary mucinous neoplasm (IPMN-associated carcinoma)](https://onco.cc/cancers/ipmn-associated-carcinoma/), [Large cell neuroendocrine carcinoma of the lung](https://onco.cc/cancers/lung-lcnec/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Lymphomatoid papulosis](https://onco.cc/cancers/lymphomatoid-papulosis/), [Lynch syndrome-associated colorectal cancer](https://onco.cc/cancers/lynch-associated-colorectal-cancer/), [Mantle cell lymphoma](https://onco.cc/cancers/mantle-cell-lymphoma/), [Mediastinal grey zone lymphoma](https://onco.cc/cancers/mediastinal-grey-zone-lymphoma/), [Mesothelioma](https://onco.cc/cancers/mesothelioma/), [Micropapillary adenocarcinoma of the colon and rectum](https://onco.cc/cancers/colorectal-micropapillary-carcinoma/), [Mismatch-repair deficient (MSI-high) colorectal cancer](https://onco.cc/cancers/msi-high-colorectal/), [Mismatch-repair-deficient endometrial cancer](https://onco.cc/cancers/endometrial-mmr-deficient/), [Monomorphic epitheliotropic intestinal T-cell lymphoma](https://onco.cc/cancers/monomorphic-epitheliotropic-intestinal-t-cell-lymphoma/), [Mucinous cystic neoplasm of the pancreas with associated invasive carcinoma (MCN-associated carcinoma)](https://onco.cc/cancers/mcn-associated-carcinoma/), [Multisystem Langerhans cell histiocytosis (with or without risk-organ involvement)](https://onco.cc/cancers/lch-multisystem/), [Mycosis fungoides](https://onco.cc/cancers/mycosis-fungoides/), [Neuroendocrine tumours](https://onco.cc/cancers/neuroendocrine/), [Nodal T-follicular helper cell lymphoma, angioimmunoblastic type (angioimmunoblastic T-cell lymphoma)](https://onco.cc/cancers/angioimmunoblastic-t-cell-lymphoma/), [Nodular lymphocyte-predominant Hodgkin lymphoma (nodular lymphocyte-predominant B-cell lymphoma)](https://onco.cc/cancers/nodular-lymphocyte-predominant-hodgkin-lymphoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Ocular adnexal MALT lymphoma](https://onco.cc/cancers/ocular-adnexal-malt-lymphoma/), [p53-abnormal endometrial cancer, including uterine serous carcinoma](https://onco.cc/cancers/endometrial-p53-abnormal/), [Paget disease of the nipple](https://onco.cc/cancers/paget-disease-of-the-nipple/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)](https://onco.cc/cancers/peripheral-t-cell-lymphoma/), [Phyllodes tumour of the breast](https://onco.cc/cancers/phyllodes-tumour/), [Placental-site trophoblastic tumour and epithelioid trophoblastic tumour](https://onco.cc/cancers/placental-site-trophoblastic-tumour/), [Plasmablastic lymphoma](https://onco.cc/cancers/plasmablastic-lymphoma/), [POLE-ultramutated endometrial cancer](https://onco.cc/cancers/endometrial-pole-ultramutated/), [Primary CNS lymphoma](https://onco.cc/cancers/primary-cns-lymphoma/), [Primary cutaneous anaplastic large cell lymphoma](https://onco.cc/cancers/primary-cutaneous-anaplastic-large-cell-lymphoma/), [Primary effusion lymphoma](https://onco.cc/cancers/primary-effusion-lymphoma/), [Primary large B-cell lymphoma of the testis](https://onco.cc/cancers/primary-testicular-lymphoma/), [Primary mediastinal (thymic) large B-cell lymphoma](https://onco.cc/cancers/primary-mediastinal-b-cell-lymphoma/), [Prostate cancer](https://onco.cc/cancers/prostate/), [Rosai-Dorfman-Destombes disease](https://onco.cc/cancers/rosai-dorfman-disease/), [Single-system Langerhans cell histiocytosis (bone, skin or one other organ)](https://onco.cc/cancers/lch-single-system/), [Sinonasal undifferentiated carcinoma (SNUC) and SWI/SNF-deficient sinonasal carcinoma](https://onco.cc/cancers/sinonasal-undifferentiated-carcinoma/), [Small-cell lung cancer](https://onco.cc/cancers/sclc/), [Solid pseudopapillary neoplasm of the pancreas](https://onco.cc/cancers/solid-pseudopapillary-neoplasm/), [Systemic mastocytosis](https://onco.cc/cancers/systemic-mastocytosis/), [T-cell/histiocyte-rich large B-cell lymphoma](https://onco.cc/cancers/t-cell-histiocyte-rich-large-b-cell-lymphoma/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/), [Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells](https://onco.cc/cancers/pancreatic-undifferentiated-carcinoma-ogc/), [Vaginal adenocarcinoma (including DES-associated clear cell adenocarcinoma)](https://onco.cc/cancers/vaginal-adenocarcinoma/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/)
- companies: [Agilent Technologies (Dako)](https://onco.cc/companies/agilent/), [Cyted Health](https://onco.cc/companies/cyted-health/), [Digistain](https://onco.cc/companies/digistain/), [HistoWiz](https://onco.cc/companies/histowiz/), [Ibex Medical Analytics](https://onco.cc/companies/ibex-medical-analytics/), [Leica Biosystems (Danaher)](https://onco.cc/companies/leica-biosystems/)
- terms: [Biomarker](https://onco.cc/terms/biomarker/), [Biopsy](https://onco.cc/terms/biopsy/), [Cell of origin in practice: Hans against expression profiling, and what it changes](https://onco.cc/terms/lymphoma-bio-cell-of-origin-in-practice/), [Circumferential resection margin (rectal cancer)](https://onco.cc/terms/circumferential-resection-margin/), [Classical versus basal-like (squamous) subtypes of pancreatic cancer, and GATA6](https://onco.cc/terms/classical-vs-basal-like/), [Core needle biopsy and fine-needle aspiration (FNA)](https://onco.cc/terms/core-needle-biopsy/), [CpG island methylator phenotype (CIMP)](https://onco.cc/terms/cimp/), [Cribriform growth pattern in prostate cancer](https://onco.cc/terms/cribriform-prostate-cancer/), [FISH / ISH (in situ hybridisation)](https://onco.cc/terms/fish/), [Gene amplification and copy-number change](https://onco.cc/terms/gene-amplification/), [Gene expression](https://onco.cc/terms/gene-expression/), [H&E staining (haematoxylin and eosin)](https://onco.cc/terms/h-and-e-staining/), [HER2-low and HER2-ultralow](https://onco.cc/terms/her2-low/), [HERACLES criteria (HER2 in bowel cancer)](https://onco.cc/terms/heracles-criteria/), [Histology](https://onco.cc/terms/histology/), [Hormone receptor status (ER / PR)](https://onco.cc/terms/hormone-receptor-status/), [Immunohistochemistry (IHC)](https://onco.cc/terms/ihc/), [Immunoscore](https://onco.cc/terms/immunoscore/), [Intraductal carcinoma of the prostate (IDC-P)](https://onco.cc/terms/intraductal-carcinoma-prostate/), [Ki-67 in triple-negative breast cancer](https://onco.cc/terms/ki-67-in-tnbc/), [Neuroendocrine tumour grade (Ki-67) and WHO classification](https://onco.cc/terms/net-grade-ki67/), [Pancreatic intraepithelial neoplasia (PanIN), the microscopic precursor of pancreatic cancer](https://onco.cc/terms/panin/), [PD-L1 expression testing (22C3, SP142, SP263)](https://onco.cc/terms/pd-l1-testing/), [Polyp types in the bowel](https://onco.cc/terms/colorectal-polyp-types/), [R0 and R1 margins in pancreatic cancer: the 1 mm rule and standardised specimen reporting](https://onco.cc/terms/r0-r1-margin-pancreatic/), [Serrated pathway](https://onco.cc/terms/serrated-pathway/), [Spread through air spaces (STAS)](https://onco.cc/terms/spread-through-air-spaces/), [The Hodgkin microenvironment: when the cancer cell is the minority](https://onco.cc/terms/lymphoma-bio-hodgkin-microenvironment/), [TTF-1 and p40 (how lung histology is decided)](https://onco.cc/terms/ttf1-p40/), [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/)
- key papers: [A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer](https://onco.cc/key-papers/paper-rimm-pd-l1-assay-comparison-jama-oncol-2017/), [Assessment of a HER2 scoring system for colorectal cancer: results from a validation study](https://onco.cc/key-papers/paper-valtorta-her2-scoring-colorectal-heracles-mod-pathol-2015/), [Atezolizumab for first-line treatment of PD-L1-selected patients with NSCLC](https://onco.cc/key-papers/paper-herbst-impower110-atezolizumab-pd-l1-nejm-2020/), [CheckMate 026: first-line nivolumab in stage IV or recurrent non-small-cell lung cancer](https://onco.cc/key-papers/paper-checkmate-026-first-line-nivolumab-nejm-2017/), [Clonal history and genetic predictors of transformation into small-cell carcinomas from lung adenocarcinomas](https://onco.cc/key-papers/paper-lee-clonal-history-small-cell-transformation-jco-2017/), [Combined tumour suppressor defects characterise clinically defined aggressive variant prostate cancers](https://onco.cc/key-papers/paper-aparicio-aggressive-variant-prostate-tumour-suppressors-ccr-2016/), [Deficient mismatch repair system in patients with sporadic advanced colorectal cancer](https://onco.cc/key-papers/paper-koopman-deficient-mismatch-repair-advanced-colorectal-bjc-2009/), [DESTINY-Breast04: trastuzumab deruxtecan works in HER2-low breast cancer, creating a new treatable group](https://onco.cc/key-papers/paper-destiny-breast04-nejm-2022/), [DESTINY-Breast06: trastuzumab deruxtecan before any chemotherapy in hormone-receptor-positive, HER2-low or ultralow breast cancer](https://onco.cc/key-papers/paper-destiny-breast06-nejm-2024/), [Galon 2006: the type, density and location of immune cells in colorectal tumours predict outcome](https://onco.cc/key-papers/paper-galon-immune-contexture-colorectal-science-2006/), [HER2 overexpression and amplification as a potential therapeutic target in colorectal cancer: analysis of 3256 patients enrolled in the QUASAR, FOCUS and PICCOLO colorectal cancer trials](https://onco.cc/key-papers/paper-richman-her2-amplification-quasar-focus-piccolo-j-pathol-2016/), [Identification of Lynch syndrome among patients with colorectal cancer](https://onco.cc/key-papers/paper-moreira-lynch-syndrome-identification-jama-2012/), [Integrative analyses of colorectal cancer show Immunoscore is a stronger predictor of patient survival than microsatellite instability](https://onco.cc/key-papers/paper-mlecnik-immunoscore-msi-colorectal-immunity-2016/), [International validation of the consensus Immunoscore for the classification of colon cancer](https://onco.cc/key-papers/paper-pages-immunoscore-international-validation-lancet-2018/), [Intraductal and ductal histology and lymphovascular invasion are associated with germline DNA-repair gene mutations in prostate cancer](https://onco.cc/key-papers/paper-isaacsson-velho-intraductal-germline-dna-repair-prostate-2018/), [IPATential150: ipatasertib plus abiraterone and prednisolone in metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-ipatential150-ipatasertib-abiraterone-pten-lancet-2021/), [KEYNOTE-010 (Herbst 2016): pembrolizumab versus docetaxel in previously treated PD-L1-positive lung cancer](https://onco.cc/key-papers/paper-keynote-010-lancet-2016/), [KEYNOTE-024: pembrolizumab alone beats chemotherapy in PD-L1-high lung cancer](https://onco.cc/key-papers/paper-keynote-024-nejm-2016/), [KEYNOTE-177: pembrolizumab instead of chemotherapy as first treatment for mismatch-repair-deficient metastatic colorectal cancer](https://onco.cc/key-papers/paper-keynote-177-nejm-2020/), [MET exon 14 mutations in non-small-cell lung cancer are associated with advanced age and stage-dependent MET genomic amplification and c-Met overexpression](https://onco.cc/key-papers/paper-awad-met-exon-14-mutations-lung-jco-2016/), [Molecular biomarkers for the evaluation of colorectal cancer: guideline from ASCP, CAP, AMP and ASCO](https://onco.cc/key-papers/paper-sepulveda-molecular-biomarkers-colorectal-guideline-jco-2017/), [Molecular characterisation of neuroendocrine prostate cancer and identification of new drug targets](https://onco.cc/key-papers/paper-beltran-nepc-aurka-mycn-cancer-discov-2011/), [Molecular profiling stratifies diverse phenotypes of treatment-refractory metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-labrecque-mcrpc-phenotypes-jci-2019/), [MSH2 loss in primary prostate cancer](https://onco.cc/key-papers/paper-guedes-msh2-loss-primary-prostate-ccr-2017/), [PD-L1 Immunohistochemistry Assays for Lung Cancer: Results from Phase 1 of the Blueprint PD-L1 IHC Assay Comparison Project](https://onco.cc/key-papers/paper-hirsch-j-thorac-oncol/), [PD-L1 immunohistochemistry comparability study in real-life clinical samples: results of Blueprint phase 2 project](https://onco.cc/key-papers/paper-blueprint-phase-2-pd-l1-assays-jto-2018/), [Proposed morphologic classification of prostate cancer with neuroendocrine differentiation](https://onco.cc/key-papers/paper-epstein-neuroendocrine-prostate-morphologic-classification-ajsp-2014/), [Prostate-specific membrane antigen expression in normal and malignant human tissues](https://onco.cc/key-papers/paper-silver-psma-expression-normal-malignant-tissues-ccr-1997/), [PTEN protein loss and clinical outcome from castration-resistant prostate cancer treated with abiraterone acetate](https://onco.cc/key-papers/paper-ferraldeschi-pten-protein-loss-abiraterone-eur-urol-2015/), [Recurrent IDH2 R172X mutations in sinonasal undifferentiated carcinoma](https://onco.cc/key-papers/paper-jo-idh2-r172-mutations-snuc-mod-pathol-2017/), [RUBY: dostarlimab with chemotherapy for advanced or recurrent endometrial cancer](https://onco.cc/key-papers/paper-ruby-nejm-2023/), [SCLC subtypes defined by ASCL1, NEUROD1, POU2F3, and YAP1: a comprehensive immunohistochemical and histopathologic characterization](https://onco.cc/key-papers/paper-baine-sclc-subtype-immunohistochemistry-jto-2020/), [SPOTLIGHT: zolbetuximab, the first Claudin 18.2 antibody, added to chemotherapy in gastric cancer](https://onco.cc/key-papers/paper-spotlight-lancet-2023/), [The genomic landscape of SMARCA4 alterations and associations with outcomes in patients with lung cancer](https://onco.cc/key-papers/paper-schoenfeld-smarca4-alterations-lung-ccr-2020/), [The TMPRSS2-ERG rearrangement, ERG expression and prostate cancer outcomes: a cohort study and meta-analysis](https://onco.cc/key-papers/paper-pettersson-tmprss2-erg-outcome-meta-analysis-cebp-2012/), [Updated molecular testing guideline for the selection of lung cancer patients for treatment with targeted tyrosine kinase inhibitors](https://onco.cc/key-papers/paper-lindeman-lung-molecular-testing-guideline-jto-2018/)
- journals: [Analytical cellular pathology (Amsterdam)](https://onco.cc/journals/analytical-cellular-pathology/), [Cancer cytopathology](https://onco.cc/journals/cancer-cytopathology/), [Head and neck pathology](https://onco.cc/journals/head-and-neck-pathology/), [Pathology oncology research](https://onco.cc/journals/pathology-and-oncology-research/)
- pairings: [HER2-low scoring → T-DXd](https://onco.cc/pairings/her2-low-to-tdxd/), [Histology → first-line choice in mesothelioma](https://onco.cc/pairings/histology-directs-first-line-meso/)
- biomarkers: [BCL2 rearrangement, t(14;18)](https://onco.cc/biomarkers/bcl2-rearrangement/), [Double expressor: MYC and BCL2 protein together by immunohistochemistry](https://onco.cc/biomarkers/myc-bcl2-double-expressor/), [TMPRSS2-ERG fusion (and the other ETS rearrangements)](https://onco.cc/biomarkers/tmprss2-erg-fusion/), [Treatment-emergent neuroendocrine transformation (recognising it)](https://onco.cc/biomarkers/nepc-transformation/)
- technologies: [Histology automation and IHC autostainers](https://onco.cc/technologies/ihc-autostainers-histology-automation/), [Immunoglobulin and T-cell receptor clonality testing](https://onco.cc/technologies/clonality-testing/), [Methylation classifier for sarcomas](https://onco.cc/technologies/sarcoma-methylation-classifier/), [MSI and mismatch-repair testing](https://onco.cc/technologies/msi-mmr-testing/), [Pre-analytics: blood-collection tubes and tissue fixation](https://onco.cc/technologies/preanalytics-sample-stabilisation/), [RAD51 foci assay (functional HRD test)](https://onco.cc/technologies/rad51-foci-assay/), [Reference laboratories and companion-diagnostic testing](https://onco.cc/technologies/reference-laboratories/)
- ideas: [A same-week expert second opinion for every rare cancer diagnosis](https://onco.cc/ideas/idea-bio2-rare-cancer-telepathology-network/), [A short pre-surgery drug window as the default early test of new agents](https://onco.cc/ideas/idea-tr1-window-of-opportunity-default/), [A standard evaluation pathway for AI-assisted pathology, from reader study to deployment](https://onco.cc/ideas/idea-data-ai-pathology-evaluation-standard/), [AI quantification of HER2-low and HER2-ultralow](https://onco.cc/ideas/idea-ai-her2-low-scoring/), [Calibrated reference slides so every lab scores HER2-low the same way](https://onco.cc/ideas/idea-tr2-her2-low-reference-materials/), [Digitise the nation's pathology slides and link them to outcomes](https://onco.cc/ideas/idea-data-national-slide-archive/), [Every pathology and genomic report ships with a signed plain-language version](https://onco.cc/ideas/idea-moon-results-in-plain-words/), [Monitor biomarker positivity rates across labs in real time to catch assay drift](https://onco.cc/ideas/idea-tr2-positivity-rate-surveillance/), [One digital PD-L1 scale that maps across all the competing assays](https://onco.cc/ideas/idea-tr2-pdl1-digital-calibration/), [Only use antibodies proven to hit their target with knockout controls](https://onco.cc/ideas/idea-tr2-antibody-validation-mandate/), [Publish each laboratory's biomarker proficiency results](https://onco.cc/ideas/idea-tr2-eqa-public-results/), [Re-map the tumour's surface proteins before choosing the next antibody drug](https://onco.cc/ideas/idea-bio1-antigen-mapping-at-progression/), [Re-test the metastasis, not the old primary, before every change of treatment](https://onco.cc/ideas/idea-bio1-rebiopsy-before-switch/), [Record how long tissue waited before fixation in every pathology report](https://onco.cc/ideas/idea-tr2-preanalytics-in-report/), [The pathology lab triggers a trial referral the day a rare cancer is diagnosed](https://onco.cc/ideas/idea-tr1-pathology-triggered-referral/), [TIL-based omission of chemotherapy in stage I TNBC](https://onco.cc/ideas/idea-til-guided-deescalation/), [Use SLFN11 status to decide which antibody-drug payload to give next](https://onco.cc/ideas/idea-bio1-slfn11-payload-guidance/)
- people: [Carsten Denkert](https://onco.cc/people/carsten-denkert/), [Ian Cree](https://onco.cc/people/cree-ian/), [Mitch Dowsett](https://onco.cc/people/mitch-dowsett/), [Reinhard Büttner](https://onco.cc/people/reinhard-buettner/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [Most of the world has almost no cancer care](https://onco.cc/bottlenecks/b-global-access/)
- institutions: [Leeds Cancer Centre, St James's University Hospital](https://onco.cc/institutions/leeds-cancer-centre/), [Tohoku University Hospital](https://onco.cc/institutions/tohoku-university-hospital/)
- pathways: [Basement membrane & tissue barriers](https://onco.cc/pathways/basement-membrane-tissue-barriers/), [Invasion: proteases, adhesion & the invasive front](https://onco.cc/pathways/invasion-ecm-degradation/), [Lineage plasticity & neuroendocrine transformation](https://onco.cc/pathways/lineage-plasticity-neuroendocrine/), [Mismatch repair & microsatellite instability](https://onco.cc/pathways/mismatch-repair-msi/)
- drugs: [HER2 IHC and ISH companion assays (HercepTest, PATHWAY 4B5, HER2 Dual ISH)](https://onco.cc/drugs/her2-testing-assays/), [PD-L1 IHC 22C3 pharmDx](https://onco.cc/drugs/dako-pd-l1-22c3-pharmdx/), [VENTANA MMR RxDx Panel](https://onco.cc/drugs/ventana-mmr-rxdx/), [VENTANA PD-L1 (SP142) Assay](https://onco.cc/drugs/ventana-pd-l1-sp142/), [VENTANA PD-L1 (SP263) Assay](https://onco.cc/drugs/ventana-pd-l1-sp263/)
- roadmaps: [Diagnostics roadmap: stains → gene panels → blood tests that decide treatment](https://onco.cc/roadmaps/diagnostics-roadmap/)
- trials: [ALCHEMIST (Adjuvant Lung Cancer Enrichment Marker Identification and Sequencing Trials)](https://onco.cc/trials/alchemist/), [FOCUS4](https://onco.cc/trials/focus4/)

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JSON: https://onco.cc/api/v1/entities/histopathology-ihc.json