Virtual Library
Start Your Search
C. Hann
Author of
-
+
MINI 27 - Biology and Other Issues in SCLC (ID 152)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Small Cell Lung Cancer
- Presentations: 1
- Moderators:P.A. Bunn, Jr, J. Sage
- Coordinates: 9/09/2015, 16:45 - 18:15, 605+607
-
+
MINI27.03 - PD-L1 Expression in Small Cell Lung Carcinoma: An Immunohistochemical Analysis of 26 Cases Using Two Anti-PD-L1 Antibodies (ID 2936)
16:55 - 17:00 | Author(s): C. Hann
- Abstract
- Presentation
Background:
Small cell lung carcinoma (SCLC) represents 15% of lung cancers and is treated using chemotherapy +/- radiation but despite initial responses most recur within a few months and become resistant to therapy. Novel immune checkpoint inhibition of programmed death-1 (PD1) targeted therapy has shown promise in other solid tumors including non-small-cell lung cancer (NSCLC) and malignant melanoma. In some tumor types correlation with response and significant expression of programmed death- ligand 1 (PD-L1), the lead candidate biomarker of anti-PD-1 therapy, has been described but no data is available regarding expression levels in SCLC. Here we report the rate of PD-L1 expression in SCLC and in associated tumor infiltrating immune cells lymphocytes and macrophages.
Methods:
Immunohistochemistry (IHC) for PD-L1 using two monoclonal antibodies (clone 5H1 and clone SP142) and for CD3 (clone PS1) was performed on standard formalin fixed paraffin embedded tissue sections of 21 resected SCLC specimens (median age: 67) and three additional tumors with pre- and post-therapy biopsies. Since there is no generally accepted scoring system for PD-L1 expression we chose to evaluate staining in tumor cells and immune cells infiltrating the tumor nests and in adjacent stroma using a 4 tier semi quantitative scoring system (score 0 -no or <1%, 1+ 1-<5%, 2+ 5-25% and 3+ >25% of cells staining). Both cytoplasmic and membranous staining was accepted as positive. The number of tumor infiltrating lymphocytes (TIL) were estimated utilizing a CD3 stain while macrophages were identified on corresponding H&E stains.
Results:
PD-L1 staining of tumor cells and Immune Cells (TIL & Macrophage) are shown in the table below. Membranous PD-L1 staining was only seen in two tumors and in variable number of immune cells with 2+ or 3+ PD-L1 scores. The majority of positive staining was cytoplasmic with both antibodies. The staining intensity was stroger with the 5H1 antibody. The paired pre- and post-therapy samples were all negative for PD-L1.
* Tumors with membranous staining; IC: immune cellsClone/score PD-L1 staining in 5H1 Tumor IC in tumor IC in stroma 0 (<1%) 19/21 (90%) 7/21 (33%) 5/21 (24%) 1+ (1-<5%) 1/21 (5%)* 11/21 (53%) 6/21 (29%) 2+ (5-25%) 1/21 (5%)* 3/21 (14%) 7/21 (33%) 3+ (>25%) 3/21 (14%) SP142 Tumor IC in tumor IC in stroma 0 (<1%) 20/21 (95%) 8/21 (38%) 10/21 (48%) 1+ (1-<5%) 1/21 (5%)* 11/21 (52%) 7/21 (33%) 2+ (5-25%) 2/21 (10%) 4/21 (19%) 3+ (>25%)
Conclusion:
Most SCLC are tumor membrane PD-L1 negative by IHC. A subset of SCLC contain PD-L1 positive TILs and/or macrophages in the tumor and the stroma. No up regulation of PD-L1 expression was seen in a small pilot sample of matched pre- and post-therapy biopsies. It is unclear whether PD-L1 expression assessed by IHC will be a predictive marker for PD-1 targeted therapy in SCLC. Preliminary data indicates single agent and combined checkpoint inhibitors (PD1 plus CTLA-4 inhibitors) are active in previously treated SCLC indicating additional research is required to understand their mechanism of action in a tumor type that has seen no therapeutic advances in the last two decades.
Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
-
+
ORAL 25 - Biology and Other Issues in SCLC (ID 125)
- Event: WCLC 2015
- Type: Oral Session
- Track: Small Cell Lung Cancer
- Presentations: 1
- Moderators:J. Sage, L. Montuenga
- Coordinates: 9/08/2015, 10:45 - 12:15, 605+607
-
+
ORAL25.07 - DNA Methylation in Small Cell Lung Cancer Defines Distinct Disease Subtypes and Correlates with High Expression of EZH2 (ID 3031)
11:50 - 12:01 | Author(s): C. Hann
- Abstract
- Presentation
Background:
Small cell lung cancer (SCLC) is an aggressive neuroendocrine lung tumor characterized by extreme plasticity, high metastatic potential, and capacity for acquired resistance to chemotherapy. Despite significant advances in our understanding of SCLC genetics and etiology, the epigenetics of this deadly disease remain under studied. This study profiles DNA methylation in primary SCLC, patient-derived xenografts (PDX) and cell lines at single-nucleotide resolution.
Methods:
This study profiled DNA methylation at single-nucleotide resolution in 47 extensively characterized SCLC samples, including 34 fresh frozen primary SCLC tumors as well as 6 distinct primary patient-derived xenografts and 7 cell lines using the Illumina Human Methylation 450k Bead Chip array. Importantly, 24 primary SCLC in this study have previously been analyzed by whole exome sequencing and RNAseq, allowing integrated analysis of these data types with measurements of DNA methylation. We applied unsupervised clustering, discrete and locally clustered differential methylation analysis, correlation with gene expression, spacial correlation with genomic features, and interrogated the role of the EZH2 methyltransferase in SCLC using bioinformatic and pharmacologic approaches.
Results:
Unsupervised clustering of all samples revealed that PDX clustered with primary SCLC, while cell lines were easily discriminated. We explored this phenomenon further and found that while the top differentially methylated CpGs in both PDX and cell lines were >80% concordant with primary SCLC, only PDX maintained high concordance across larger probe lists. Unsupervised clustering of primary SCLC revealed three distinct subgroups at both the DNA methylation and gene expression levels that correlated with expression of the neurogenic transcription factors ASCL1 and NEUROD1. The chromatin modifier EZH2 was expressed >12-fold higher in SCLC than in normal lung. In addition to the high expression observed in SCLC compared to normal lung, we observed a significant correlation between median EZH2 gene expression and promoter methylation using data from The Cancer Genome Atlas (TCGA). Overall, EZH2 expression in SCLC is greater than or comparable to that of any other tumor type represented in TCGA. EZH2 protein expression was detected by Western blot in 15/17 SCLC PDXs (88%). We assessed the efficacy of the potent EZH2 inhibitor EPZ-5687 in the LX92 SCLC PDX in vivo. EPZ-5687 was well-tolerated and demonstrated remarkable efficacy at 100 mg/kg either QD or BID.
Conclusion:
DNA methylation patterns in primary SCLC are more closely mirrored by those found in PDX, compared to cell lines, including PDX lines of very high passage. Distinct epigenetic subtypes could be observed in SCLC, even among histologically indistinguishable samples with similar mutation profiles. SCLC is notable for consistent high level DNA methylation clustered in promoters containing CpG islands. Promoter methylation in SCLC is distinct from other lung cancers and correlates strongly with high-level expression of the histone methyltransferase gene EZH2. Pharmacologic inhibition of EZH2 in a SCLC PDX markedly inhibited tumor growth. These findings point to a critical role of EZH2 in SCLC tumor biology and support further preclinical efficacy studies in models of SCLC.
Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
