Somatic Driver Mutation Discovery & Drug Match Report in Lung Cancer
Scientific Objective: Process raw paired-end Whole Exome Sequencing (WES) reads from matched tumor-normal biopsies of lung adenocarcinoma (LUAD) patients, call high-confidence somatic Single Nucleotide Variants (SNVs) and Indels, annotate functional consequences against ClinVar and COSMIC, and generate clinical waterfall and oncoplot visual summaries highlighting therapeutic vulnerabilities (EGFR, ALK, KRAS).
5-Phase Execution Roadmap
- Phase 1: Raw Quality Control & Adapter Trimming: Run
fastpwith--detect_adapter_for_pe, generate MultiQC report, ensure mean base quality > Q30. - Phase 2: Alignment & Preprocessing: Align with
bwa-mem2against GRCh38, sort withsamtools sort, mark optical/PCR duplicates usinggatk MarkDuplicates, and apply Base Quality Score Recalibration (BQSR). - Phase 3: Somatic Mutation Calling: Execute
gatk Mutect2in paired mode using a Panel of Normals (PoN) and gnomAD germline resource, followed bygatk FilterMutectCallsto discard oxoG artifacts and strand bias. - Phase 4: Variant Annotation & Filtering: Annotate with Ensembl VEP (SIFT, PolyPhen-2, ClinVar), filter for
FILTER == 'PASS'and Allele Frequency < 0.001 in population databases. - Phase 5: Downstream Oncogenomics & Visualization: Convert VCF to MAF format using
vcf2maf, generate co-mutation matrix and lollipop mutation diagrams in R withmaftools, and query OncoKB for FDA-approved targeted therapies.
gatk Mutect2 -R reference.fasta -I tumor.bam -I normal.bam -normal NORMAL_SAMPLE_ID \
--germline-resource af-only-gnomad.vcf.gz --panel-of-normals pon.vcf.gz -O raw_somatic.vcf.gz
gatk FilterMutectCalls -R reference.fasta -V raw_somatic.vcf.gz -O filtered_somatic.vcf.gz