[BUG] Type Error loading Mutational Signatures tab

[obsidian0815]

Describe the bug

When loading the Mutational Signatures tab in the Patient View for a locally imported study, the page crashes with a JavaScript TypeError. The data is correctly imported and accessible via the API, but the frontend fails to render it.

TypeError: can't access property "name", r.props.data[r.props.version][0].meta is undefined

To Reproduce

1. Import a study with mutational signature data using the following meta file configuration:

cancer_study_identifier: <study_id>
genetic_alteration_type: GENERIC_ASSAY
generic_assay_type: MUTATIONAL_SIGNATURE
datatype: LIMIT-VALUE
stable_id: contributions_SBS
profile_name: SBS Mutational Signature Contributions
profile_description: SBS contribution scores from SigProfilerAssignment
data_filename: data_mutational_signature_contribution_SBS.txt
show_profile_in_analysis_tab: false
pivot_threshold_value: 0.05
value_sort_order: DESC
generic_entity_meta_properties: NAME,DESCRIPTION,URL

With a data file in this format:

ENTITY_STABLE_ID	NAME	DESCRIPTION	URL	<SAMPLE_ID>
SBS1	SBS1	COSMIC mutational signature SBS1	https://cancer.sanger.ac.uk/signatures/sbs/sbs1/	6.57
SBS30	SBS30	COSMIC mutational signature SBS30	https://cancer.sanger.ac.uk/signatures/sbs/sbs30/	0

2. Navigate to the Patient View of a sample in that study.
3. Click the Mutational Signatures tab.
4. See error: TypeError: can't access property "name", r.props.data[r.props.version][0].meta is undefined

Expected behavior

The mutational signature bar chart is displayed correctly for the sample.

Screenshots

N/A

Additional context

• cBioPortal version: v6.4.1
• Deployment: local instance

The data is correctly stored in the database. API investigation:

GET /api/generic-assay-meta/MUTATIONAL_SIGNATURE?projection=SUMMARY → returns []

GET /api/generic-assay-meta/<studyId>_contributions_SBS?projection=SUMMARY → returns correct entities with NAME, DESCRIPTION, URL

POST /api/generic_assay_data/fetch with body:

{
  "sampleMolecularIdentifiers": [
    { "molecularProfileId": "<studyId>_contributions_SBS", "sampleId": "<sampleId>" },
    { "molecularProfileId": "<studyId>_pvalues_SBS",       "sampleId": "<sampleId>" },
    { "molecularProfileId": "<studyId>_ci_width_SBS",      "sampleId": "<sampleId>" }
  ]
}

→ returns correct data for all three profiles

The /api/generic-assay-meta/MUTATIONAL_SIGNATURE endpoint returning [] may be the root cause — the frontend may rely on this endpoint to populate .meta before rendering.

Additionally, datatype: P-VALUE, documented as valid for mutational signature p-value files, is rejected by the importer with Could not determine the file type. Only LIMIT-VALUE is accepted by the importer, which may be a related inconsistency.

[dippindots]

@obsidian0815 we recently updated the mutational signatures file format, and the previous format is now outdated. Could you take a look at the updated documentation: https://docs.cbioportal.org/file-formats/#mutational-signature-data?

You can also find an example study for reference here:
https://github.com/cBioPortal/datahub/tree/master/public/msk_impact_50k_2026