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F. Khalil
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MINI 02 - Immunotherapy (ID 92)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:P. Forde, S.J. Antonia
- Coordinates: 9/07/2015, 10:45 - 12:15, Four Seasons Ballroom F3+F4
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MINI02.12 - Distribution of Immune Markers and Their Association with Overall Survival and Time to Progression in Non-Small-Cell Lung Cancer (NSCLC) (ID 3108)
11:50 - 11:55 | Author(s): F. Khalil
- Abstract
- Presentation
Background:
Inducible nitric oxide synthase (iNOS) and reactive nitrosylation are important mediators of tumor immunosuppression by myeloid-derived suppressor cells (MDSCs). However, the role of CD33+ peritumoral PMN-MDSCs in these pathways remains unclear. We conducted a retrospective cohort study of NSCLC subjects treated with surgery, with the primary objective to determine the association of MDSC biomarkers with time to progression (TTP) and overall survival (OS).
Methods:
Inclusion criteria: Surgically treated NSCLC of all stages at a single institution between 1996 and 2010. Somatic mutations tested by PCR. Anti-human antibodies optimized for immunohistochemistry. Samples scored by blinded pathologist based on intensity and percentage of peritumoral cells. Peritumoral nitrotyrosine (NT) and iNOS used Allred scoring. Time to progression (TTP) defined as time from resection to progression event or censored at last evaluation. Overall survival (OS) defined as time from resection to death.
Results:
Of 458 tumor samples, 366 lung primaries, 38 soft tissue metastases, and 39 brain metastases. Demographics: median age 67 yrs, 54% female, 96% Caucasian. Of 151 tested for somatic mutations, 36% KRASm, 8.6% EGFRm, 25% p53m, respectively. Histology: adenocarcinoma 76%, squamous 10%. Higher % CD3+ tumor infiltrating lymphocytes (TILs) and CD33+ myeloid cells were observed in tumors than normal tissue (p < .0001 and p = .002, respectively). More CD3+ TILs observed in soft tissue metastases than primary lung tumors (p < .0001). No difference in iNOS expression between tumor and normal lung tissue. More CD3+ TIL was observed in p53 mutant tumors (p=.03). iNOS was positively correlated with CD3+ TIL (p < .001) and CD73+ epithelial cells (p <.001), but not CD33+ myeloid cells. NT expression correlated with the absence of CD3+ TIL (p = .02), consistent with its putative immunosuppressive activity. Median TTP: 10.4 months; 320 (69.7%) events. Median OS: 35.4 months; 353 (77.1%) events. Expectedly, presence of CD3+ TIL was associated with favorable OS; HR 0.5 [0.4 – 0.7], p < .0001, and TTP; HR 0.7 [.5 – .9], p =.009. CD33+ myeloid cells were associated with favorable OS; HR 0.6 [0.5-0.8], p = .0002. Presence of peritumoral iNOS trended toward favorable OS; HR 0.81 [0.6-1.0], p = .07. Peritumoral iNOS was not associated with TTP. Figure 1
Conclusion:
Increased presence of TILs in p53 mutant tumors has been reported in other cancers, and may be related to somatic mutational load. An inflamed tumor phenotype was associated with improved overall survival. Unexpectedly, iNOS was positively correlated with both CD3+ infiltration and overall survival.
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MINI 13 - Genetic Alterations and Testing (ID 120)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:Y. Koh, R.K. Thomas
- Coordinates: 9/08/2015, 10:45 - 12:15, 205+207
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MINI13.03 - Characterization of MET Gene and MET Protein Expression in Lung Cancer (ID 2155)
10:55 - 11:00 | Author(s): F. Khalil
- Abstract
- Presentation
Background:
Activation of the MET signaling pathway can propel the growth of cancer cells in non-small cell lung cancer (NSCLC). Increased MET gene by amplification and/or polysomy can cause MET protein overexpression; less common causes include mutations, translocations, and alternative RNA splicing. Clinical trials using MET as a biomarker for selection of lung cancer patients who might most benefit from targeted therapy have experienced variable outcomes. We aimed to characterize the relationship between MET protein overexpression and MET amplification or mean copy number alterations in patients with NSCLC.
Methods:
The Lung Cancer Mutation Consortium (LCMC) is performing an ongoing study of biomarkers with patients with NSCLC from 16 cancer center sites across the United States. For this analysis, 403 cases had complete data for MET protein expression by immunohistochemistry (IHC, monoclonal antibody SP44, Ventana) and MET gene amplification by fluorescence in-situ hybridization (FISH, MET/CEP7 ratio). Pathologists evaluated MET expression using the H-score, a semi-quantitative assessment of the percentage of tumor cells with no, faint, moderate, and/or strong staining, ranging from 0-300. Spearman's correlation was used to analyze the correlation between MET protein expression (H-scores) and FISH results (MET/CEP7 ratio (N=403) and MET copy number (N=341). Protein overexpression using 5 different cut-offs was compared with amplification defined as MET/CEP7 ≥ 2.2 and high mean copy number defined as ≥ 5 MET gene copies per cell using the Fisher’s exact test. Cox Proportional Hazards models were built to examine the associations of these different definitions of positivity with prognosis, adjusting for stage of disease.
Results:
MET protein expression was significantly correlated with MET copy numbers (r=0.17, p=0.0025), but not MET/CEP7 ratio (r=-0.013, p=0.80). No significant association was observed between protein overexpression using a commonly used definition for MET positivity (“at least moderate staining in ≥ 50% tumor cells”) and MET amplification (p=0.47) or high mean copy number (p=0.09). A definition for MET protein overexpression as “≥ 30% tumor cells with strong staining” was significantly associated with both MET amplification (p=0.03) and high mean copy number (p=0.007), but a definition of “≥ 10% tumor cells with strong staining” was not significantly associated with either. Definitions of protein overexpression based on high H-scores (≥200 or ≥250) were associated with high MET mean copy numbers (p=0.03 and 0.0008, respectively), but not amplification (p=0.46 and 0.12, respectively). All 5 definitions of MET protein overexpression demonstrated a significant association with worse prognosis by survival analyses (p-values ranged from 0.001 to 0.03). High MET copy number (p=0.045) was associated with worse prognosis, but MET amplification was not (p=0.07).
Conclusion:
Evaluation of NSCLC specimens from LCMC sites confirms that MET protein expression is correlated with high MET copy number and protein overexpression is associated with worse prognosis. Definitions of MET protein overexpression as “an H-score ≥250” and “≥30% tumor cells with strong staining” were significantly associated with high mean MET copy number. It may be worth reevaluating the performance of MET as a biomarker by different definitions of positivity to predict response to MET-targeted therapies.
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ORAL 37 - Novel Targets (ID 146)
- Event: WCLC 2015
- Type: Oral Session
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:S.S. Ramalingam, E. Thunnissen
- Coordinates: 9/09/2015, 16:45 - 18:15, Mile High Ballroom 4a-4f
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ORAL37.07 - Lung Cancer Mutation Consortium Pathologist Panel Evaluation of MET Protein (ID 2129)
17:50 - 18:01 | Author(s): F. Khalil
- Abstract
- Presentation
Background:
MET is a receptor tyrosine kinase with frequently activated signaling in lung cancers. Multiple studies indicate that MET overexpression correlates with poor clinical prognosis. Tumors with MET amplification and overexpression may respond better to MET inhibitors than tumors with low expression. The prevalence of MET overexpression in lung cancer cohorts has varied from 20%-80%, as has the proportion of patient’s testing positive for prospective clinical trials with entry based on MET overexpression. The Lung Cancer Mutation Consortium (LCMC) Pathologist Panel endeavored to standardize evaluation of MET protein expression with “Round Robin” conferences.
Methods:
508 FFPE non-small cell lung cancer specimens were stained by immunohistochemistry for MET protein expression (SP44 antibody, Ventana). Seven pathologists from LCMC sites with specialized training in MET scoring evaluated 78 Aperio-scanned images of MET-stained slides in two successive rounds of 39 different cases per round. The percentage of tumor cells with membranous and/or cytoplasmic staining at different intensities were evaluated with H-scores ranging from 0 to 300. Overall group and individual pathologist’s scores were compared with intraclass correlation coefficients (ICCs). Between rounds, a “Round Robin” teleconference was conducted to review discordant cases and improve consistency of scoring. Steps to improve scoring included: review of a Roche MET training document, sharing pictures of cases with concordant scores (Figure 1), and provision of H&E images for the second round to facilitate identification of tumor areas. Figure 1
Results:
The overall average MET H-score for the 78 cases was 165.3 (H-score range: 42.5-279.7). The average H-score was <125 for 14 specimens, 125-175 for 35 specimens, and >175 for 29 specimens. The overall group ICC comparing the consistency of H-scores from all 7 pathologists improved from 0.50 (95% confidence interval: 0.37-0.64, “fair” correlation) for the first scoring round to 0.74 (95% confidence interval: 0.64-0.83, “good” correlation) for the second round. A comparison of the individual pathologist’s ICCs demonstrated improved individual scoring consistency for all seven pathologists between rounds with an average of 0.64 (“moderate” correlation, range 0.43-0.76) for the first round and 0.82 (“almost perfect” correlation, range 0.75-0.93) for the second round.
Conclusion:
Development of standardized, reproducible strategies for evaluation of complex biomarkers, such as MET, are critical to clinical trial design. The consistency of scoring for MET protein expression and other biomarkers may be improved by continuous training and communication between pathologists with easy access to H&E images and other visual aids.
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