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M. Nilsson
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P2.02 - Biology/Pathology (ID 616)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.02-015 - Mutation Patterns in a Swedish Non-Small Cell Lung Cancer Cohort (ID 10048)
09:30 - 09:30 | Author(s): M. Nilsson
- Abstract
Background:
Non-small cell lung cancer (NSCLC) is a heterogeneous disease with unique combinations of somatic molecular alterations in individual patients, as well as significant differences in populations across the world with regard to mutation spectra and mutation frequencies. Here we describe the mutational pattern and linked clinical parameters in a population-based Swedish NSCLC cohort.
Method:
The cohort consists of 354 patients treated surgically at the University Hospital in Uppsala between 2006 to 2010. DNA was extracted from either fresh frozen (n=200) or formalin fixed paraffin embedded (FFPE; n=154) tissues prior to library preparation with Haloplex capture probes and Illumina Hiseq sequencing. The gene panel covers all exons of 82 genes, that have been shown to harbor mutations relevant for NSCLC development, and utilizes a reduced target fragment length and two strand capture compatible with degraded FFPE samples.
Result:
In order to avoid a systematic technical bias between FFPE and fresh-frozen samples, we adapted the sequencing depth and the bioinformatic pipeline for variant calling to obtain uniform sequence coverage and mutational load across the two sample types. TP53 was the most frequently mutated gene in both adenocarcinoma (AdC; 47%) and squamous cell carcinoma (SqC; 85%). KEAP1 or NFE2L2 was mutated in 19% of AdC and 23% of SqC in a mutually exclusive fashion. In AdC, hotspot alterations in driver genes could be seen in KRAS (43%), EGFR (13%), ERBB2 (3%, exon 20 insertions), BRAF (2%) and MET (1%, exon 14 skipping). Mutations in STK11 were observed in 21% of AdC cases. In SqC, frequently mutated genes were MLL2 (26%), PIK3CA (20%), CDKN2A (15%) and DDR2 (4%). Survival analysis revealed a worse overall survival for AdC patients with a mutation in either TP53, STK11 or SMARCA4. In the KRAS-mutated group poor survival appeared to be linked to concomitant TP53 or STK11 mutations, and not to KRAS mutation as a single aberration. In SqC a worse overall survival could be observed for patients with MLL2 mutations. SqC patients with mutations in CSMD3 had trend for a better prognosis.
Conclusion:
Here we have evaluated the mutational status of a Swedish NSCLC cohort. Technical adaption allowed analysis across both FFPE and fresh-frozen samples. Overall, the high frequency of TP53 and KRAS mutations might be related to the large fraction of smokers. Poor prognosis was linked to mutations in TP53, STK11 or SMARCA4 in AdC and MLL2 mutations in SqC.
