RARE DISEASERESEARCH ATLAS
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ORPHA:631251

Cancer of unknown primary site

low confidenceDisorder

Also known as: CUP · Carcinoma of unknown primary · Carcinoma of unknown primary origin · Metastases without primary tumor

Publications

3,821

Trials

67

Interventional, condition-specific

Researchers

1,395

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

2/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    3,821 matched papers (2,362 in last 10 years) Source

  3. Phenotype characterisedNot checked

    Not yet enriched from Monarch / HPO

  4. Animal modelNot checked

    Not yet enriched from Monarch / Alliance

  5. Orphan designationNot checked

    FDA/EMA orphan-drug designation not enriched yet

  6. Interventional trialPresent

    67 matched on ClinicalTrials.gov (13 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

Not enriched in this build — Monarch phenotype joins were not run for this record.

Animal models (Monarch / Alliance)

Not enriched in this build.

Literature

Is anyone studying this?

3,821

3,821 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.

3,821 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).

2,362 in the last 10 years · low confidence

Phrase hits: 3,821 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,395

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Naing A4 papers · 2026

    Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

    Papers in Europe PMC
  2. 02
    Bakshi JB3 papers · 2025

    Department of Otorhinolaryngology and Head-Neck Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012 India.

    Papers in Europe PMC
  3. 03
    Chettuvatti K3 papers · 2025

    Department of Otorhinolaryngology and Head-Neck Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012 India.

    Papers in Europe PMC
  4. 04
    Kim J3 papers · 2026

    Department of Pathology, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu, Republic of Korea.

    Papers in Europe PMC
  5. 05
    Panda NK3 papers · 2025

    Department of Otorhinolaryngology and Head-Neck Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012 India.

    Papers in Europe PMC
  6. 06
    Raghav K3 papers · 2026

    Department of Gastrointestinal Medical Oncology, University of Texas M.D. Anderson Cancer Center, Houston.

    Papers in Europe PMC
  7. 07
    Stephen B3 papers · 2026

    Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

    Papers in Europe PMC
  8. 08
    Subbiah V3 papers · 2026

    Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

    Papers in Europe PMC
  9. 09
    Topf MC3 papers · 2026

    Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

    Papers in Europe PMC
  10. 10
    Wheatley-Price P3 papers · 2026

    Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

67

interventional trials for this specific condition

67 interventional trials matched this specific condition name; 13 currently recruiting in our sample.

Data as of 27 July 2026

67 interventional trials — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 97.8th percentile).

low confidence · 97.8th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

67 interventional trials matched after quoted-phrase search and title/condition post-filter.

Observational and natural-history studies

9 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

Where to find support

We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"Cancer of unknown primary site" OR "Cancer of the unknown primary site" OR "Carcinoma of unknown primary" OR "Carcinoma of the unknown primary" OR "Carcinoma of unknown primary origin" OR "Carcinoma of the unknown primary origin" OR "Metastases without primary tumor"

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Cancer of unknown primary site" OR "Cancer of the unknown primary site" OR "Carcinoma of unknown primary" OR "Carcinoma of the unknown primary" OR "Carcinoma of unknown primary origin" OR "Carcinoma of the unknown primary origin" OR "Metastases without primary tumor"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 67 interventional · 9 observational · 0 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: CUP

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (3821) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-27T19:26:59.583Z