Biomarker Consortium

GU Cancer

Bladder Cancer

 (nectin cell adhesion molecule 4; formerly PVRL4) encodes a single-pass type I transmembrane protein of the nectin family.

Nectin-4 mediates cell adhesion through homophilic and heterophilic interactions; a soluble form is released by ADAM17 cleavage. Its high expression on urothelial carcinoma and limited expression in normal tissue make it a target for antibody-drug conjugates.

 in 2394 specimens, 69% were Nectin-4-positive by IHC, with moderate to strong staining in 60% of bladder tumors.

 87% of NMIBC and 50 of 86 MIBC were positive in one series; expression was low in sarcomatoid (10%) and absent in small cell (0%) tumors. Expression was lower after neoadjuvant chemotherapy and varied between primary and nodal specimens.

 found in about 26% of metastatic urothelial carcinoma and about 17% of TCGA MIBC; amplification is stable during metastatic progression.

Nectin-4 testing is not required before enfortumab vedotin. Its indications are defined by disease setting and prior therapy, not by Nectin-4 expression.

 no FDA-approved Nectin-4 assay exists, and no cut point has been clinically validated.

 in a retrospective cohort, NECTIN4 amplification by FISH was associated with a 96% response rate to enfortumab vedotin vs 32% without amplification (HR for death, 0.08). A 2026 scoring system combining amplification with membranous IHC is under study. Cytoplasmic expression was not predictive.

No guideline recommends routine Nectin-4 testing. NCCN designates enfortumab vedotin plus pembrolizumab as the only preferred first-line regimen for locally advanced or metastatic urothelial carcinoma, regardless of cisplatin eligibility, based on clinical setting rather than a Nectin-4 result.

With pembrolizumab (IV or subcutaneous), as neoadjuvant and then adjuvant treatment after cystectomy for adults with MIBC (cisplatin-ineligible, November 21, 2025; all patients, July 10, 2026).

With pembrolizumab for adults with locally advanced or metastatic urothelial cancer (la/mUC).

As a single agent for la/mUC after a PD-1/PD-L1 inhibitor and platinum chemotherapy, or in cisplatin-ineligible patients after 1 or more prior lines.

Nectin-4-directed antibody conjugated to the microtubule-disrupting agent monomethyl auristatin E (MMAE) through a protease-cleavable linker; after internalization, released MMAE causes cell-cycle arrest and apoptosis.

NCBI Gene. NECTIN4 nectin cell adhesion molecule 4 [Homo sapiens]. Gene ID 81607. Accessed October 2026.

Challita-Eid PM, Satpayev D, Yang P, et al. Enfortumab vedotin antibody-drug conjugate targeting Nectin-4 is a highly potent therapeutic agent in multiple preclinical cancer models. 

. 2016;76(10):3003-3013. doi:10.1158/0008-5472.CAN-15-1313

Hoffman-Censits JH, Lombardo KA, Parimi V, et al. Expression of Nectin-4 in bladder urothelial carcinoma, in morphologic variants, and nonurothelial histotypes. 

. 2021;29(8):619-625. doi:10.1097/PAI.0000000000000938

Miyake M, Miyamoto T, Shimizu T, et al. Tumor expression of Nectin-1-4 and its clinical implication in muscle invasive bladder cancer: an intra-patient variability of Nectin-4 expression. 

. 2022;237:154072. doi:10.1016/j.prp.2022.154072

Klümper N, Tran NK, Zschäbitz S, et al. NECTIN4 amplification is frequent in solid tumors and predicts enfortumab vedotin response in metastatic urothelial cancer. 

. 2024;42(20):2446-2455. doi:10.1200/JCO.23.01983

Padcev (enfortumab vedotin-ejfv) for injection. Prescribing information. Astellas Pharma US, Inc; revised 07/2026. Accessed October 2026.

Klümper N, Büttner T, Rauch S, et al. Integrating NECTIN4 amplification with membranous Nectin-4 expression to develop a scoring system for predicting enfortumab vedotin response in urothelial carcinoma. 

. Published online September 9, 2026. doi:10.1158/1078-0432.CCR-26-0093

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Bladder Cancer V.2.2026. © National Comprehensive Cancer Network, Inc. 2026. All rights reserved. Accessed October 2026. To view the most recent and complete version of the guideline, go online to NCCN.org.

Nectin-4

 is tumor-derived DNA in plasma cell-free DNA. 

 is detectable ctDNA after curative-intent surgery in a patient with no radiographic evidence of disease.

 sequencing of the resected tumor and matched normal blood identifies patient-specific somatic variants, which are then tracked in plasma by personalized multiplex PCR and deep NGS.

ctDNA detected after radical cystectomy reflects microscopic residual disease and precedes radiographic relapse; in one cohort, post-cystectomy ctDNA identified metastatic relapse with 100% sensitivity and 98% specificity, a median of 96 days before imaging.

ctDNA status identifies which patients are likely to benefit from adjuvant immunotherapy: in IMvigor010, atezolizumab improved disease-free survival (HR, 0.58) and overall survival (HR, 0.59) only in ctDNA-positive patients, with no difference in ctDNA-negative patients.

 (214 of 581) of patients with high-risk muscle-invasive urothelial carcinoma in IMvigor010 were ctDNA-positive at the start of adjuvant therapy; ctDNA positivity carried a 6.3-fold higher risk of recurrence (HR, 6.3; 95% CI, 4.45-8.92) in the observation arm.

 of 761 enrolled patients under serial surveillance, 250 became ctDNA-positive and were randomized; 357 remained persistently ctDNA-negative, with 1-year disease-free survival of 95.4% without adjuvant therapy.

After radical cystectomy for MIBC in patients without radiographic evidence of disease: begin at least 6 weeks after cystectomy, test every 6 weeks for 9 months, with a final test at 1 year. Patients who remain negative continue serial testing until a positive result or completion of the 12-month window.

 FDA-approved companion diagnostic (PMA P260004, May 15, 2026), the first approved blood-based MRD companion diagnostic. Whole-exome sequencing of FFPE tumor (at least 20% tumor content) and matched whole blood removes germline and clonal hematopoiesis variants and selects 16 tumor-specific variants; plasma is positive when at least 2 of 16 are detected.

 limit of detection 0.043% mean variant allele fraction; 0 of 309 false positives in limit-of-blank testing.

 recommends considering ctDNA MRD testing with an FDA-approved tumor-informed multiplex PCR-NGS assay for risk stratification and to guide adjuvant immunotherapy after cystectomy in patients without prior checkpoint inhibitor therapy; adjuvant atezolizumab for ctDNA MRD-positive status within 1 year of cystectomy is category 1 (other recommended).

As a single agent for adjuvant treatment of adults with MIBC after cystectomy who have ctDNA MRD as determined by an FDA-authorized test (May 15, 2026).

Humanized IgG1 monoclonal antibody that binds PD-L1 and blocks its interaction with PD-1 and B7.1, releasing PD-L1/PD-1-mediated inhibition of the antitumor immune response.

Persistently ctDNA-negative patients had excellent outcomes without adjuvant therapy in IMvigor011, supporting ctDNA-guided de-escalation; earlier unselected atezolizumab trials did not improve outcomes, and atezolizumab's prior metastatic urothelial indications were withdrawn in 2021 and 2022.

Powles T, Assaf ZJ, Davarpanah N, et al. ctDNA guiding adjuvant immunotherapy in urothelial carcinoma. 

. 2021;595(7867):432-437. doi:10.1038/s41586-021-03642-9

Christensen E, Birkenkamp-Demtröder K, Sethi H, et al. Early detection of metastatic relapse and monitoring of therapeutic efficacy by ultra-deep sequencing of plasma cell-free DNA in patients with urothelial bladder carcinoma. 

. 2019;37(18):1547-1557. doi:10.1200/JCO.18.02052

Signatera CDx. Summary of safety and effectiveness data, PMA P260004. US Food and Drug Administration. May 15, 2026.

Powles T, Kann AG, Castellano D, et al. ctDNA-guided adjuvant atezolizumab in muscle-invasive bladder cancer. 

. 2025;393(24):2395-2408. doi:10.1056/NEJMoa2511885

Powles T, et al. IMvigor011: a phase 3 trial of ctDNA-guided adjuvant atezolizumab versus placebo in MIBC. Presented at: ESMO Congress 2025; abstract LBA8.

Tecentriq (atezolizumab) injection. Prescribing information. Genentech, Inc; revised 05/2026. Accessed October 2026.

FDA approves atezolizumab for adjuvant treatment of muscle invasive bladder cancer in patients with molecular residual disease. US Food and Drug Administration. May 15, 2026.

ctDNA MRD

 (fibroblast growth factor receptor 3) and 

 (fibroblast growth factor receptor 2) encode receptor tyrosine kinases of the FGFR family (FGFR1 to FGFR4).

 Chromosome 4 (4p16.3) for FGFR3; chromosome 10 (10q26.13) for FGFR2.

Each FGFR has 3 extracellular immunoglobulin-like domains, a transmembrane domain, and an intracellular kinase domain. Binding of 1 of 22 FGF ligands causes dimerization and activation of RAS-MAPK, PI3K-AKT, PLCγ, and STAT signaling, which regulate proliferation, differentiation, survival, and angiogenesis.

 R248C, S249C, G370C, and Y373C create cysteine residues that form disulfide bonds between receptors, causing ligand-independent dimerization and constitutive signaling. S249C is the most common, accounting for up to about 70% of FGFR3 mutations.

 FGFR3-TACC3 and FGFR3-BAIAP2L1 join the FGFR3 kinase to partner domains that drive oligomerization and activation.

FGFR3-altered tumors are enriched in the luminal-papillary subtype of muscle-invasive bladder cancer (MIBC), which has lower immune infiltration.

Locally advanced or metastatic urothelial carcinoma (la/mUC): approximately 20%

 of tumors have FGFR3 alterations; about 80% of these are point mutations, FGFR3 fusions are less common, and FGFR2 alterations are rare.

 FGFR3 mutations occur in around 70% of non-muscle-invasive bladder cancers (NMIBC) and about 15% of MIBC.

 about 40% harbor FGFR3 alterations; in one series, FGFR3 was altered in 35.6% of high-grade UTUC vs 21.6% of high-grade bladder tumors.

 FGFR aberrations were found in 7.1% of 4853 solid tumors sequenced by NGS, with urothelial carcinoma among the most frequently altered tumor types.

In the TCGA MIBC cohort, luminal-papillary tumors (35% of 408 MIBC) carried most FGFR3 mutations, amplifications, and FGFR3-TACC3 fusions.

Patients with la/mUC should undergo FGFR3 testing at diagnosis of advanced disease so results are available when second-line therapy is chosen.

 (FFPE tumor tissue) is the FDA-approved companion diagnostic for erdafitinib. It detects FGFR3 R248C, S249C, G370C, and Y373C mutations and FGFR3-TACC3 fusions (variants 1 and 3); turnaround is about 3 to 5 days.

 detects mutations, fusions, and copy-number changes in one assay (about 5 to 21 days); RNA-based sequencing is preferred for fusions. In THOR cohort 1, 25% of patients were identified by local NGS.

 archival FFPE tissue from the diagnostic sample (TURBT or upper tract) is generally appropriate. ctDNA is less accurate for fusions, and urine-based testing remains investigational.

 test all patients with la/mUC for FGFR3 at diagnosis with a validated qPCR or NGS assay.

 recommends molecular testing in advanced disease, including FGFR3 alterations, to guide erdafitinib eligibility.

Adults with la/mUC with susceptible FGFR3 genetic alterations whose disease has progressed on or after at least 1 prior line of systemic therapy. Not recommended for patients eligible for, but not yet treated with, PD-1 or PD-L1 inhibitor therapy.

Oral, reversible, ATP-competitive inhibitor of FGFR1 to FGFR4 kinase activity. Serum phosphate rises with on-target FGFR inhibition and is used to guide dose uptitration.

TAR-210 (intravesical erdafitinib releasing system):

 investigational in NMIBC with susceptible FGFR alterations identified by urine or TURBT tissue testing; phase 3 MoonRISe-1 (NCT06319820) and MoonRISe-3 (NCT06919965) are enrolling.

NCBI Gene. FGFR3 (Gene ID 2261) and FGFR2 (Gene ID 2263) [Homo sapiens]. Accessed October 2026.

Du S, Zhang Y, Xu J. Current progress in cancer treatment by targeting FGFR signaling. 

. 2023;20(7):490-499. doi:10.20892/j.issn.2095-3941.2023.0137

Bogale DE. The roles of FGFR3 and c-MYC in urothelial bladder cancer. 

. 2024;15(1):295. doi:10.1007/s12672-024-01173-z

Helsten T, Elkin S, Arthur E, et al. The FGFR landscape in cancer: analysis of 4,853 tumors by next-generation sequencing. 

. 2016;22(1):259-267. doi:10.1158/1078-0432.CCR-14-3212

Robertson AG, et al. Comprehensive molecular characterization of muscle-invasive bladder cancer. 

. 2017;171(3):540-556.e25. doi:10.1016/j.cell.2017.09.007

Mansinho A, et al. FGFR testing in metastatic urothelial carcinoma: who, when, and how to test. 

. 2026;18(3):444. doi:10.3390/cancers18030444

Maguire WF, Chang E, Mulkey F, et al. FDA approval summary: erdafitinib for FGFR3-altered locally advanced or metastatic urothelial carcinoma. 

. Published online August 12, 2026. doi:10.1158/1078-0432.CCR-26-1154

Sfakianos JP, et al. Genomic characterization of upper tract urothelial carcinoma. 

. 2015;68(6):970-977. doi:10.1016/j.eururo.2015.07.039

Compérat EM, et al. FGFR3 testing in urothelial carcinoma: an expert commentary on best practices from patient identification to result reporting. 

. 2026;9(4):977-985. doi:10.1016/j.euo.2026.06.003

Balversa (erdafitinib) tablets. Prescribing information. Janssen Products, LP; revised 10/2025. Accessed October 2026.

ClinicalTrials.gov. MoonRISe-1 (NCT06319820) and MoonRISe-3 (NCT06919965). Accessed October 2026.

FGFR3

 (erb-b2 receptor tyrosine kinase 2), also called HER2 or neu, encodes a transmembrane receptor tyrosine kinase of the epidermal growth factor receptor (EGFR) family.

HER2 is a proto-oncogene product with no ligand-binding domain of its own; it heterodimerizes with ligand-bound family members, enhancing MAPK and PI3K signaling that drives proliferation, differentiation, and resistance to apoptosis.

In urothelial carcinoma, HER2 expression is associated with luminal/urothelial-like and genomically unstable subtypes and is enriched in micropapillary histology.

HER2 expression is common but varies by series:

 overexpression is reported in 9% to 61% of bladder cancers; in one series of 284 patients, 44% had IHC 2+/3+ (51% bladder vs 38% upper tract).

 41% of 105 specimens scored IHC 3+ with gastric (upper GI) criteria vs 34% with breast criteria in a 2026 series; IHC 3+ was enriched in micropapillary (79%) and plasmacytoid (60%) tumors and brain metastases (40%).

 7.4% of 820 cystectomy specimens by FISH (micropapillary 19%, conventional urothelial carcinoma 8%) and 12.4% of nodal metastases.

Patients with unresectable or metastatic urothelial carcinoma who have received prior systemic therapy and are being considered for trastuzumab deruxtecan.

 there is no urothelial-specific HER2 scoring system. DESTINY-PanTumor02 used ASCO/CAP gastric cancer scoring criteria with central HercepTest testing; breast and gastric criteria give divergent scores in a meaningful subset of urothelial tumors.

 HER2 expression varies spatially within tumors (multiple biopsies improve accuracy), and nodal metastases can show higher expression and amplification than primaries.

 in DESTINY-PanTumor02, local and central results agreed for 58.6% of IHC 3+ and 54.5% of IHC 2+ cases.

 none. The label states that an FDA-authorized test for HER2-positive (IHC 3+) solid tumors is not currently available. NGS can detect ERBB2 amplification or mutation but does not replace IHC.

 lists fam-trastuzumab deruxtecan as biomarker-directed therapy for HER2-positive (IHC 3+) disease and notes it may be useful in certain circumstances for IHC 2+ disease without other satisfactory options; gastric IHC scoring is recommended.

Fam-Trastuzumab Deruxtecan-nxki (Enhertu)

As monotherapy for adults with unresectable or metastatic HER2-positive (IHC 3+) solid tumors who have received prior systemic treatment and have no satisfactory alternative options (accelerated approval, April 5, 2024).

Humanized anti-HER2 IgG1 antibody linked through a cleavable tetrapeptide linker to deruxtecan, a topoisomerase I inhibitor. After internalization, the linker is cleaved and the payload causes DNA damage and apoptosis.

Learn more about Fam-Trastuzumab Deruxtecan ›

 HER2-directed ADC, not FDA approved. It received Breakthrough Therapy designation (2020) for previously treated HER2-positive urothelial carcinoma. In the phase 3 RC48-C016 trial in China, disitamab vedotin plus toripalimab improved PFS (13.1 vs 6.5 months; HR, 0.36) and OS (31.5 vs 16.9 months; HR, 0.54) vs chemotherapy in first-line HER2-expressing urothelial carcinoma. The global phase 3 SGNDV-001 trial with pembrolizumab (NCT05911295) is ongoing.

HGNC. ERBB2 (HGNC:3430). Accessed October 2026.

Rubin I, Yarden Y. The basic biology of HER2. 

. 2001;12(suppl 1):S3-S8. doi:10.1093/annonc/12.suppl_1.s3

Schechter AL, Stern DF, Vaidyanathan L, et al. The neu oncogene: an erb-B-related gene encoding a 185,000-Mr tumour antigen. 

. 1984;312(5994):513-516. doi:10.1038/312513a0

Dernbach G, Eich ML, Dragomir MP, et al. Spatial expression of HER2, NECTIN4, and TROP-2 in muscle-invasive bladder cancer and metastases: implications for pathological and clinical management. 

. 2025;38(7):100753. doi:10.1016/j.modpat.2025.100753

Bhardwaj S, Morris E, Halthore A, et al. Assessing human epidermal growth factor receptor 2 in urothelial carcinoma: insights from clinical practice into scoring criteria, histologic subtypes, and genomic characteristics across disease sites. 

. Published online June 30, 2026. doi:10.5858/arpa.2025-0386-OA

Zhou L, Shao Z, Liu Y, et al. HER2 expression associated with clinical characteristics and prognosis of urothelial carcinoma in a Chinese population. 

. 2023;28(8):e617-e624. doi:10.1093/oncolo/oyad070

Cheville JC, Tekin B, Orme JJ, et al. ERBB2 copy number alterations and protein expression in bladder cancer treated by cystectomy. 

. 2026;176:106217. doi:10.1016/j.humpath.2026.106217

Enhertu (fam-trastuzumab deruxtecan-nxki) for injection. Prescribing information. Daiichi Sankyo, Inc; revised 05/2026. Accessed October 2026.

Meric-Bernstam F, Makker V, Oaknin A, et al. Efficacy and safety of trastuzumab deruxtecan in patients with HER2-expressing solid tumors: primary results from the DESTINY-PanTumor02 phase II trial. 

. 2024;42(1):47-58. doi:10.1200/JCO.23.02005

Makker V, Lee JY, Oh DY, et al. Post hoc analysis of the phase II DESTINY-PanTumor02 study: local and central HER2 IHC concordance and trastuzumab deruxtecan efficacy by HER2 IHC status in HER2-expressing solid tumors. 

. 2026;32(13):2628-2636. doi:10.1158/1078-0432.CCR-25-4702

Sheng X, Zeng G, Zhang C, et al. Disitamab vedotin plus toripalimab in HER2-expressing advanced urothelial cancer. 

. 2025;393(23):2324-2337. doi:10.1056/NEJMoa2511648

ClinicalTrials.gov. SGNDV-001 (NCT05911295). Accessed October 2026.

HER2

Biomarkers

2019. Tumor-agnostic HER2-positive (IHC 3+) solid tumor indication: accelerated approval April 5, 2024, which remains accelerated in the 05/2026 label.

Unresectable or Metastatic HER2-Positive (IHC 3+) Solid Tumors:

unresectable or metastatic HER2-positive (IHC 3+) solid tumors

 who have received prior systemic treatment and have no satisfactory alternative treatment options. Continued approval may depend on confirmatory trials.

 HER2-positive (IHC 3+) tumor specimens. An FDA-authorized test for this indication is not currently available.

 (21-day cycle) until disease progression or unacceptable toxicity. Do not substitute with trastuzumab or ado-trastuzumab emtansine.

DESTINY-PanTumor02 (NCT04482309), DESTINY-Lung01 (NCT03505710), DESTINY-CRC02 (NCT04744831)

 previously treated HER2-positive (IHC 3+) solid tumors; the 111 IHC 3+ patients in DESTINY-PanTumor02 included 27 with bladder cancer.

 fam-trastuzumab deruxtecan 5.4 mg/kg every 3 weeks (single arm); response by independent central review.

 approval is based on single-arm response data; no randomized comparison or survival benefit has been demonstrated for this indication, and the bladder subgroup is small. Responses also occurred with IHC 2+ bladder tumors (ORR 35.0%; n=20), but IHC 2+ disease is outside the indication.

HER2-Positive (IHC 3+) Solid Tumors (N=347)

 serious adverse reactions 34%, fatal 6.3% (ILD 2.3%), discontinuation 15% (ILD 10%), dose reduction 27%, dose interruption 48%.

 ILD/pneumonitis (16% in this population; 12% across 2233 pooled patients, fatal in 0.9%); neutropenia; left ventricular dysfunction; embryo-fetal toxicity.

Wysocki PJ, et al. DESTINY-PanTumor02 bladder cancer cohort [abstract 4565]. J Clin Oncol. 2024;42(16 suppl):4565. doi:10.1200/JCO.2024.42.16_suppl.4565

Makker V, Lee JY, Oh DY, et al. Post hoc analysis of the phase II DESTINY-PanTumor02 study. 

FDA grants accelerated approval to fam-trastuzumab deruxtecan-nxki for unresectable or metastatic HER2-positive solid tumors. US Food and Drug Administration. April 5, 2024.

Bladder Cancer

Fam-Trastuzumab Deruxtecan-nxki

Initial US Approval

Indications

Unresectable or Metastatic HER2-Positive (IHC 3+) Solid Tumors:

Recommended Dose/Route

Dose Reductions for Adverse Reactions

Pivotal Study

DESTINY-PanTumor02 (NCT04482309), DESTINY-Lung01 (NCT03505710), DESTINY-CRC02 (NCT04744831)

Safety

HER2-Positive (IHC 3+) Solid Tumors (N=347)

References