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H. Brunnström
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MA 05 - Immuno-Oncology: Novel Biomarker Candidates (ID 658)
- Event: WCLC 2017
- Type: Mini Oral
- Track: Immunology and Immunotherapy
- Presentations: 1
- Moderators:Yoichi Nakanishi, P. Mitchell
- Coordinates: 10/16/2017, 15:45 - 17:30, Room 303 + 304
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MA 05.13 - Scavenger Receptor MARCO Defines a Targetable Tumor-Associated Macrophage Subset in Lung Cancer (ID 8641)
15:45 - 17:30 | Author(s): H. Brunnström
- Abstract
- Presentation
Background:
Tumor-associated macrophages (TAMs) with immunosuppressive and tumor promoting features are attractive targets for immunotherapy. MARCO is a scavenger receptor expressed on a subpopulation of macrophages in secondary lymphoid organs. A recent study performed in animal models concluded that treatment with an anti-MARCO antibody results in reprogramming of the TAMs and inhibition of tumor growth and metastatic spread. The expression and function of MARCO in lung cancer TAMs is not known.
Method:
The infiltration of TAMs expressing MARCO, CD68, CD163 and MSR1, in the tumor and stromal compartments, was analyzed by immunohistochemistry in a non-small cell lung cancer (NSCLC) cohort (n=352). In addition, PD-L1 expression was assessed on tumor cells. Immunofluorescence was performed on selected cases to evaluate marker co-expression. Associations to immune cells and regulatory inflammatory pathways were studied in a subset of cases (n=174) with available RNA-seq data.
Result:
A large variance in TAM density could be observed between cases as well as a strong correlation between CD68 and CD163, indicating a pro-tumor phenotype of infiltrating macrophages. Correlation to clinical data showed a trend towards worse survival for patients with high macrophage infiltration. TAM expression of MARCO was seen on a subpopulation of pro-tumor macrophages. The majority of MARCO expressing TAMs were found to be located within tumor cell nests. Interestingly, stromal macrophages expressing MARCO tended to aggregate in close proximity to the tumor nests. On the transcriptomic level, increased MARCO gene expression correlated to genes linked to immunosuppressive TAMs, T-cell infiltration and immune checkpoint molecules like PD-L1 and CTLA-4. The association between macrophage infiltration and tumor cell PD-L1 expression was confirmed by immunohistochemistry. Also, co-expression of PD-L1 and MARCO could be detected on certain macrophages within the tumor cell nests.
Conclusion:
MARCO expression characterizes a specific subpopulation of pro-tumor macrophages that are enriched in PD-L1 positive NSCLC cases. Patients with significant infiltration of MARCO positive TAMs could benefit from treatment with anti-MARCO antibodies, possibly in combination with available immune checkpoint inhibitors.
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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 - 16:00 | Author(s): H. Brunnström
- 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.
