Q (sonnet): In the TCGA Glioblastoma multiforme study (gbm_tcga_pan_can_atlas_2018), how many patients have an IDH1 R132H mutation and how many are IDH1 wild-type. ▶ read_guide { "uri": "cbioportal://mutation-frequency-guide" } ▶ read_guide { "uri": "cbioportal://common-pitfalls" } ◀ result # Mutation Frequency Analysis Guide ## IMPORTANT: Reporting Mutation Frequencies - **ALWAYS report frequencies as percentages**, not raw counts: `frequency = (altered_samples / total_profiled_samples) × 100` - For quick frequency lookups, **prefer the TCGA Pan-Cancer Atlas study first**, then offer to expand to other studies - When reporting across multiple studies, show **ranges** (e.g., "TP53 is mutated in 30–60% of samples") rather than a single average - **NEVER** sum mutation events across studies to compute an aggregate frequency — this can exceed 100% due to double-counting - Warn users that samples may overlap across cohorts (e.g., MSK studies may share patients) - **Choose and state the counting unit**: use patient-level frequencies for prevalence/rate questions unless the user explicitly asks for samples; use sample-level frequencies when the user asks about samples. - **For "across cancer types" questions**, jump to the [Cross-Cancer-Type Mutation Frequency](#cross-cancer-type-mutation-frequency) section below — there is one correct recipe and several common wrong ones. ## Counting Unit: Samples vs Patients Before answering any mutation count or frequency question, decide whether the unit is samples or patients and state that choice in the answer. | User wording | Counting unit | |--------------|---------------| | "prevalence", "rate", "fraction of patients", "patients with", "how common is" | Patient-level: `COUNT(DISTINCT patient_unique_id)` | | "samples", "specimens", "biopsies", sample-level cohort composition | Sample-level: `COUNT(DISTINCT sample_unique_id)` | | Ambiguous | Ask, or default to patient-level for prevalence/rate language and say so | ### Cross-study sample-count caveat When an answer touches more than one study and reports a sample count, prepend a one-line caveat: > Sample IDs are unique within cBioPortal study prefixes, not guaranteed biological-sample identifiers across studies; overlapping cohorts can count the same patient/sample more than once. Prefer one of these safer approaches: - Use a shipped `cancer_study_query_preferences` cohort such as `pan_cancer_tcga` or `all_studies_non_redundant`. - Restrict to one named study. - Aggregate by `patient_unique_id` when the biological question is patient prevalence. ## STOP rule: a frequency above 100% means your query is wrong If your query returns a frequency over 100%, **do not try to debug or explain the data inconsistency to the user**. The cause is always one of these query bugs: - Summing mutation events instead of `COUNT(DISTINCT sample_unique_id)` for the numerator - Using a study-wide sample count as the denominator instead of the gene-specific profiled count - Cross-study aggregation where the same biological sample appears under multiple `sample_unique_id` values (e.g., MSK-IMPACT and MSK-CHORD share patients) - **Joining the profiled CTE through `gene_panel` / `gene_panel_list` without a WES branch.** `gene_panel_id = 'WES'` is *not* a row in … (35166 more chars) ◀ result # Common Query Pitfalls Guide ## Overview This guide highlights frequent mistakes when analyzing cBioPortal data and provides solutions to avoid them. ## Critical Pitfalls ### 1. 🚨 CRITICAL MUTATION FREQUENCY ERRORS #### ❌ WRONG: Using study-wide totals for gene frequencies ```sql -- INCORRECT - This gives wrong frequencies! SELECT hugo_gene_symbol, COUNT(DISTINCT sample_unique_id) as altered_samples, (SELECT COUNT(DISTINCT sample_unique_id) FROM genomic_event_derived WHERE cancer_study_identifier = 'your_study_id') as total_samples FROM genomic_event_derived WHERE variant_type = 'mutation' AND cancer_study_identifier = 'your_study_id' GROUP BY hugo_gene_symbol; ``` **Problem**: Different genes have different profiling coverage - you can't use study-wide totals! #### ❌ WRONG: Not using gene-specific profiling denominators ```sql -- INCORRECT - Missing gene-specific denominators SELECT hugo_gene_symbol, COUNT(DISTINCT sample_unique_id) as altered_samples FROM genomic_event_derived WHERE variant_type = 'mutation' GROUP BY hugo_gene_symbol; -- Missing: WHERE ARE THE DENOMINATORS FOR EACH GENE? ``` #### ❌ WRONG: Skipping individual gene profiling queries **Problem**: Failing to run separate profiling queries for EACH gene in results. **Each gene has different coverage**: TP53 might be profiled in 25,040 samples, MUC16 in 23,000, etc. #### ✅ CORRECT: Complete gene-specific workflow ```sql -- STEP 1: Get altered counts per gene SELECT hugo_gene_symbol, entrez_gene_id, COUNT(DISTINCT CASE WHEN off_panel = 0 THEN sample_unique_id END) AS numberOfAlteredSamplesOnPanel, COUNT(*) AS totalMutationEvents FROM genomic_event_derived WHERE variant_type = 'mutation' AND mutation_status != 'UNCALLED' GROUP BY entrez_gene_id, hugo_gene_symbol ORDER BY numberOfAlteredSamplesOnPanel DESC; -- STEP 2: FOR EACH GENE, run this profiling query: SELECT COUNT(DISTINCT stgp.sample_unique_id) AS numberOfProfiledSamples FROM sample_to_gene_panel_derived stgp JOIN gene_panel gp ON stgp.gene_panel_id = gp.stable_id JOIN gene_panel_list gpl ON gp.internal_id = gpl.internal_id JOIN gene g ON gpl.gene_id = g.entrez_gene_id WHERE stgp.alteration_type = 'MUTATION_EXTENDED' AND g.hugo_gene_symbol = 'TP53' -- Replace with each gene from Step 1 AND stgp.cancer_study_identifier = 'your_study_id'; -- STEP 3: Calculate frequency = numberOfAlteredSamplesOnPanel / numberOfProfiledSamples * 100 ``` #### 🚨 WORKFLOW REQUIREMENTS VIOLATIONS: - **Missing denominator columns**: Must show gene-specific profiled samples per row - **Wrong table format**: Should be | Gene | # Mutations | # Samples | Profiled Samples | Sample % | - **Not replacing gene symbols**: Must replace 'TP53' with actual gene for each query - **Using study totals**: Never use genomic_event_derived for total sample counts ### 2. 🚨 OFF-PANEL MUTATION INCLUSION #### ❌ Wrong: Including off-panel mutations ```sql -- INCORRECT - Includes mutations outside gene panels SELEC … (37891 more chars) ▶ clickhouse_run_select_query { "query": "SELECT uniqExact(c.patient_unique_id) AS profiled_patients FROM sample_to_gene_panel_derived s JOIN (SELECT DISTINCT sample_unique_id, patient_unique_id FROM clinical_data_derived WHERE cancer_study_identifier = 'gbm_tcga_pan_can_atlas_2018') c USING sample_unique_id WHERE s.cancer_study_identifier = 'gbm_tcga_pan_can_atlas_2018' AND s.alteration_type = 'MUTATION_EXTENDED'" } ◀ result {"rows":[{"profiled_patients":390}]} ▶ clickhouse_run_select_query { "query": "SELECT mutation_variant, COUNT(DISTINCT patient_unique_id) AS patients FROM genomic_event_derived WHERE cancer_study_identifier = 'gbm_tcga_pan_can_atlas_2018' AND hugo_gene_symbol = 'IDH1' AND variant_type = 'mutation' AND mutation_status != 'UNCALLED' GROUP BY mutation_variant ORDER BY patients DESC" } ◀ result {"rows":[{"mutation_variant":"R132H","patients":22},{"mutation_variant":"R132G","patients":1},{"mutation_variant":"R132C","patients":1}]} ▶ resolve_and_route { "studyIds": [ "gbm_tcga_pan_can_atlas_2018" ] } ◀ result {"success":true,"message":"Found 1 study. Use the metadata to call the appropriate navigation tool(s).","data":{"totalCount":1,"studiesWithMetadata":[{"studyId":"gbm_tcga_pan_can_atlas_2018","name":"Glioblastoma Multiforme (TCGA, PanCancer Atlas)","sampleCount":592,"studyViewUrl":"https://www.cbioportal.org/study?id=gbm_tcga_pan_can_atlas_2018","metadata":{"clinicalAttributeIds":["AGE","AJCC_PATHOLOGIC_TUMOR_STAGE","AJCC_STAGING_EDITION","ANEUPLOIDY_SCORE","BUFFA_HYPOXIA_SCORE","CANCER_TYPE","CANCER_TYPE_ACRONYM","CANCER_TYPE_DETAILED","DAYS_LAST_FOLLOWUP","DAYS_TO_BIRTH","DAYS_TO_INITIAL_PATHOLOGIC_DIAGNOSIS","DFS_MONTHS","DFS_STATUS","DSS_MONTHS","DSS_STATUS","ETHNICITY","FORM_COMPLETION_DATE","FRACTION_GENOME_ALTERED","GENETIC_ANCESTRY_LABEL","GRADE","HISTORY_NEOADJUVANT_TRTYN","ICD_10","ICD_O_3_HISTOLOGY","ICD_O_3_SITE","INFORMED_CONSENT_VERIFIED","IN_PANCANPATHWAYS_FREEZE","MSI_SCORE_MANTIS","MSI_SENSOR_SCORE","MUTATION_COUNT","NEW_TUMOR_EVENT_AFTER_INITIAL_TREATMENT","ONCOTREE_CODE","OS_MONTHS","OS_STATUS","OTHER_PATIENT_ID","PATH_M_STAGE","PATH_N_STAGE","PATH_T_STAGE","PERSON_NEOPLASM_CANCER_STATUS","PFS_MONTHS","PFS_STATUS","PRIMARY_LYMPH_NODE_PRESENTATION_ASSESSMENT","PRIOR_DX","RACE","RADIATION_THERAPY","RAGNUM_HYPOXIA_SCORE","SAMPLE_COUNT","SAMPLE_TYPE","SEX","SOMATIC_STATUS","SUBTYPE","TBL_SCORE","TISSUE_PROSPECTIVE_COLLECTION_INDICATOR","TISSUE_RETROSPECTIVE_COLLECTION_INDICATOR","TISSUE_SOURCE_SITE","TISSUE_SOURCE_SITE_CODE","TMB_NONSYNONYMOUS","TUMOR_TISSUE_SITE","TUMOR_TYPE","WEIGHT","WINTER_HYPOXIA_SCORE"],"molecularProfileIds":["gbm_tcga_pan_can_atlas_2018_gistic","gbm_tcga_pan_can_atlas_2018_log2CNA","gbm_tcga_pan_can_atlas_2018_mutations","gbm_tcga_pan_can_atlas_2018_rna_seq_v2_mrna","gbm_tcga_pan_can_atlas_2018_rna_seq_v2_mrna_median_Zscores","gbm_tcga_pan_can_atlas_2018_rna_seq_v2_mrna_median_all_sample_Zscores","gbm_tcga_pan_can_atlas_2018_rppa","gbm_tcga_pan_can_atlas_2018_rppa_Zscores","gbm_tcga_pan_can_atlas_2018_structural_variants"],"genericAssayProfiles":["gbm_tcga_pan_can_atlas_2018_armlevel_cna","gbm_tcga_pan_can_atlas_2018_genetic_ancestry","gbm_tcga_pan_can_atlas_2018_methylation_hm27_hm450_merge","gbm_tcga_pan_can_atlas_2018_methylation_hm450"],"heatmapProfileIds":["gbm_tcga_pan_can_atlas_2018_rna_seq_v2_mrna_median_Zscores","gbm_tcga_pan_can_atlas_2018_rna_seq_v2_mrna_median_all_sample_Zscores","gbm_tcga_pan_can_atlas_2018_rppa_Zscores"],"availableComparisonTabs":["overlap","clinical","survival","alterations","mutations","mrna","protein","generic_assay_armlevel_cna","generic_assay_genetic_ancestry","generic_assay_methylation"]}}]}} ▶ navigate_to_results_view { "studyIds": [ "gbm_tcga_pan_can_atlas_2018" ], "genes": [ "IDH1: R132H" ], "tab": "mutations" } ◀ result {"success":true,"message":"Navigating to https://www.cbioportal.org/results/mutations?cancer_study_list=gbm_tcga_pan_can_atlas_2018&gene_list=IDH1%3A+R132H&case_set_id=gbm_tcga_pan_can_atlas_2018_all","url":"https://www.cbioportal.org/results/mutations?cancer_study_list=gbm_tcga_pan_can_atlas_2018&gene_list=IDH1%3A+R132H&case_set_id=gbm_tcga_pan_can_atlas_2018_all","data":{"studyIds":["gbm_tcga_pan_can_atlas_2018"],"studies":[{"studyId":"gbm_tcga_pan_can_atlas_2018","name":"Glioblastoma Multiforme (TCGA, PanCancer Atlas)","sampleCount":592}],"genes":["IDH1"],"caseSetId":"gbm_tcga_pan_can_atlas_2018_all","pageDescription":"Detailed mutation table with lollipop plot showing mutation positions, types, and frequencies for queried genes."}} ▶ navigate_to_group_comparison { "studyIds": [ "gbm_tcga_pan_can_atlas_2018" ], "tab": "comparison/alterations", "selectedGene": "IDH1", "groups": [ { "name": "IDH1 R132H", "studyViewFilter": { "mutationDataFilters": [ { "hugoGeneSymbol": "IDH1", "profileType": "mutations", "categorization": "MUTATION_TYPE", "values": [ [ { "value": "R132H" } ] ] } ] } }, { "name": "IDH1 Wild-type", "isUnselected": true } ] } ◀ result {"success":false,"error":"No samples found for group \"IDH1 R132H\" — filter may be too restrictive","details":{}} ▶ get_studyviewfilter_options { "studyId": "gbm_tcga_pan_can_atlas_2018", "geneSpecificQueries": [ { "hugoGeneSymbol": "IDH1", "profileType": "mutations" } ] } ◀ result {"success":true,"message":"Successfully retrieved StudyView filter options","data":{"studyId":"gbm_tcga_pan_can_atlas_2018","geneSpecificCounts":[{"hugoGeneSymbol":"IDH1","profileType":"mutations","counts":[{"value":"Missense_Mutation","label":"Missense Mutation","count":25}]}]}} ═ answer (success) The filter options only expose mutation-type categorization (e.g., "Missense_Mutation"), not specific protein-change values like R132H — that level of granularity isn't available via `mutationDataFilters` in this study's filter API. I won't force a group comparison link with an incorrect filter. Given this constraint, the ResultsView Mutations tab (already generated) is the correct and precise tool for IDH1 R132H — it shows the lollipop plot with each variant broken out, matching the query results above. ## Summary **GBM TCGA PanCancer Atlas (390 patients profiled for mutations):** | Group | Patients | % of profiled | |---|---|---| | IDH1 R132H | 22 | 5.6% | | IDH1 wild-type | 366 | 93.8% | | *(Other IDH1 variants: R132G ×1, R132C ×1 — excluded from both groups above)* | [View IDH1 Mutations in GBM (TCGA, PanCancer Atlas)](https://www.cbioportal.org/results/mutations?cancer_study_list=gbm_tcga_pan_can_atlas_2018&gene_list=IDH1%3A+R132H&case_set_id=gbm_tcga_pan_can_atlas_2018_all) Detailed mutation table with lollipop plot showing mutation positions, types, and frequencies for IDH1.