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Mari Mino-Kenudson
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MTE 02 - Appropriate and Optimized Handling of Specimens (Sign Up Required) (ID 569)
- Event: WCLC 2017
- Type: Meet the Expert
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 10/16/2017, 07:00 - 08:00, Room 316
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MTE 02.02 - Appropriate and Optimized Handling of Biopsy or Cytology Specimens (ID 7804)
07:00 - 08:00 | Presenting Author(s): Mari Mino-Kenudson
- Abstract
- Presentation
Abstract:
The recent advance in personalized medicine along with minimally invasive endoscopic techniques in the field of lung cancer has brought significant complexities to handling of tissue samples. Due to the histology-directed therapy, additional stains are frequently required to achieve accurate histologic subtyping on small biopsy and cytology samples. It is recommended that epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) and ROS1 testing be performed for patients with advanced non-squamous small cell lung cancer (NSCLC) in a reflex manner. In addition, multiplex assays, including next generation sequencing (NGS), are increasingly being used for detection of the molecular targets. Furthermore, immunohistochemistry (IHC) for programmed death ligand-1 (PD-L1) is now routinely performed in NSCLCs with wild type EGFR and ALK to determine eligibility for PD-1/PD-L1 blockade.(1) In most advanced NSCLC patients, a small biopsy or cytology specimen is often the only sample available for the diagnosis and biomarker analyses. Thus, appropriate tissue acquisition, processing and management for multiple tests are crucial and are best achieved by the interaction of all physicians involved in the patient care.(2, 3) Tissue acquisition All the necessary work-up is usually performed on a small biopsy or cytology specimen taken from a patient with advanced disease, tissue sampling should be aimed at obtaining the largest yield of tumor in the safest and least invasive manner.(4) Tissue processing Appropriate pre-analytic tissue handling is one of the keys to successful implementation of IHC-based and molecular assays in general.(3, 5) An ischemia time from tissue procurement to the initiation of fixation should be short (as short as possible), and biopsies should immediately be immersed in fixative for 6-48 hours. Of note, multiple tissue fragments in a biopsy sample (obtained from one lesion) may be submitted in a few tissue cassettes to avoid tissue exhaustion that is not infrequently seen when the single available tissue block is cut and used for multiple purposes. Neutral buffered formalin is historically the preferred and most common fixative used in the practice of histopathology.(6) Consequently, the majority of pathology laboratories typically perform the initial validation of IHC and molecular protocols on FFPE tissue. Decalcifying solutions used for bony specimens vary in their effects on retention and integrity of nucleic acids and proteins. Thus, results of IHC on decalcified specimens are unpredictable because of wide variations in specimen types and sizes, fixation time, and the particular solution(s) used.(7) Similarly, alcohol fixation used for cytology specimens, including alcohol-fixed cell blocks, decreases IHC accuracy by causing loss or decrease of immunogenicity when IHC protocols optimized with FFPE tissue samples are used.(8) For molecular assays, samples fixed with acidic solutions (including decalcifying salutations) and heavy metal fixatives are not recommended due to further degradation of nuclear acid and heavy metals hampering PCR reaction, respectively.(9) Thus, tissue sampling of a bone metastasis for this purpose should be avoided, if possible. In case the bone metastasis is the only accessible lesion for sampling, the pathologist may try to separate a soft tissue component submitted in the formalin. Up to 40% of advanced NSCLC patients are diagnosed by cytology alone. Cytology smears, cytospins and liquid-based cytology (LBC), processed from fine needle aspiration (FNA) or other modalities, are typically treated with alcohol-based solution or sprays devoid of exposure to formalin that leads to fragmentation of nuclear acids, thus often contain tumor cells with intact nucleic acid ideal for molecular testing. However, formalin-fixed paraffin-embedded (FFPE) cell blocks processed from the residual material from FNA or LBC or body fluid are the preferred samples for ancillary testing in many laboratories, since they can be handled in the same way as biopsy/resection specimens.(2) Tissue management To maximize small samples, the number of times when the tissue block needs to be cut for diagnosis, IHC and molecular testing should be minimized. It is because a decent amount of tissue is cut and wasted for trimming of the block at each round of sectioning. Thus, extra sections may be cut up front at the first cutting for diagnostic histology sections. Many pathology laboratories already have protocols in place per local requirements under close supervision by pathologists. It is also important that the pathologist is in close communication with oncologists and proceduralists to ensure that relevant clinical information is provided before sectioning is done. Diagnostic work-up between the lesion with high probability of a lung primary and a possible metastasis, and that between primary diagnosis and progression/recurrence after targeted therapy are often different, thus lack of the critical information may lead to unnecessary IHC. Last, but not least, the pathologist needs to evaluate tissue adequacy (tumor cellularity, the presence or absence of necrosis and tissue quality, etc.) before submitting samples for molecular testing. References: 1. NCCN Clinical Practice Guidelines in Oncology: Non-Small Cell Lung Cancer. Version 8.2017 – July 14, 2017. 2. Bubendorf L, Lantuejoul S, de Langen AJ, et al. Nonsmall cell lung carcinoma: diagnostic difficulties in small biopsies and cytological specimens: Number 2 in the Series "Pathology for the clinician" Edited by Peter Dorfmuller and Alberto Cavazza. Eur Respir Rev. 2017;26(144). 3. Tsao MS, Hirsch FR, Yatabe Y. IASLC atlas of ALK and ROS1 testing in lung cancer. 2nd ed. Colorado: Editorial Rx Press; 2016. 4. Thunnissen E, Kerr KM, Herth FJ, et al. The challenge of NSCLC diagnosis and predictive analysis on small samples. Practical approach of a working group. Lung Cancer. 2012;76(1):1-18. 5. Mino-Kenudson M. Programmed death-ligand 1 immunohistochemistry testing for non-small cell lung cancer in practice. Cancer. 2017;125(7):521-8. 6. Thavarajah R, Mudimbaimannar VK, Elizabeth J, et al. Chemical and physical basics of routine formaldehyde fixation. J Oral Maxillofac Pathol. 2012;16(3):400-5. 7. Fitzgibbons PL, Bradley LA, Fatheree LA, et al. Principles of analytic validation of immunohistochemical assays: Guideline from the College of American Pathologists Pathology and Laboratory Quality Center. Arch Pathol Lab Med. 2014;138(11):1432-43. 8. Zhou F, Moreira AL. Lung Carcinoma Predictive Biomarker Testing by Immunoperoxidase Stains in Cytology and Small Biopsy Specimens: Advantages and Limitations. Arch Pathol Lab Med. 2016;140(12):1331-7. 9. Lindeman NI, Cagle PT, Beasley MB, et al. Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Arch Pathol Lab Med. 2013;137(6):828-60.
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OA 07 - Biomarker for Lung Cancer (ID 659)
- Event: WCLC 2017
- Type: Oral
- Track: Biology/Pathology
- Presentations: 1
- Moderators:Philip Christopher Mack, Shinichi Toyooka
- Coordinates: 10/16/2017, 15:45 - 17:30, Room 503
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OA 07.05 - Serial Biopsies in Patients with EGFR-Mutant NSCLC Highlight the Spatial and Temporal Heterogeneity of Resistance Mechanisms (ID 10181)
15:45 - 17:30 | Author(s): Mari Mino-Kenudson
- Abstract
- Presentation
Background:
Resistance to EGFR tyrosine kinase inhibitors (TKIs) limits treatment outcomes among patients with EGFR-mutant NSCLC. Resistance mechanisms have previously been conceptualized as binary “positive/negative” variables, but emerging evidence suggests resistant cancers are heterogeneous, and subclones may be appreciated through multiple biopsies.
Method:
We retrospectively analyzed 221 EGFR mutant pts at MGH who had >1 biopsy after progression on their initial EGFR inhibitor. Data on acquired resistance (AR) mechanisms observed at each biopsy, adverse events, and treatment were collected.
Result:
Among 221 pts with a total of 355 post-AR tissue biopsies, median age was 59 (range, 28-88), 69% were female, 64% had EGFR del19, 33% L858R and 3% other activating mutations. Median number of biopsies per patient was 1 (range, 1-4). Biopsies at first resistance to EGFR TKI showed 61% T790M, 5% MET amplification (amp), 3% SCLC transformation, 2% acquired PIK3CA and 1% acquired BRAF mutations. 83 pts had two biopsies during their post-resistance course; 43/83 (52%) had heterogeneity between biopsy 1 and 2. In particular, 20% “lost” T790M, while 11% “gained” T790M. Among 17 pts who lost T790M, 3 gained a separate resistance mechanism, including MET amp and BRAF V600E. In some cases, synchronous biopsies identified spatial heterogeneity. For example, an osimertinib-resistant patient had a T790M/C797S lung nodule, while a concurrent mediastinal lymph node was wild-type at both loci (both sites retained the activating EGFR mutation). Similarly, another osimertinib-resistant patient with MET amp in a pleural effusion cell block had a lung nodule biopsy which lacked MET amp; the patient was treated with combination EGFR and MET inhibitors with a partial response. Additional details regarding concurrent liquid biopsies, treatment histories and clinical outcomes will be presented.
Conclusion:
In this large cohort of EGFR mutant NSCLC patients, we frequently observed variations in resistance mechanisms in patients with > 1 post-AR biopsy. Our data highlights the heterogeneity of resistant cancers and the limitations of a single biopsy in fully capturing the spectrum of resistance mechanisms in each patient. Serial biopsies or non-invasive methods may be required to characterize resistance and identify potential therapeutic targets.
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P1.07 - Immunology and Immunotherapy (ID 693)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Immunology and Immunotherapy
- Presentations: 1
- Moderators:
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P1.07-033 - Differential Expression of Immune Inhibitory Markers in Association with the Immune Microenvironment in Resected Lung Adenocarcinomas (ID 10196)
09:30 - 16:00 | Author(s): Mari Mino-Kenudson
- Abstract
Background:
Similar to programed death ligand 1 (PD-L1), indoleamine 2,3-Dioxygenase 1 (IDO1) is known to exert immunosuppressive effects and be variably expressed in human lung cancer. However, IDO1 expression has not been well-studied in lung adenocarcinoma (ADC).
Method:
PD-L1 and IDO1 expression were evaluated in 261 resected ADC using tissue microarrays and H-scores (cutoff 5). We compared IDO1 with PD-L1 expression in association with clinical features, tumor-infiltrating lymphocytes (TILs), HLA class I (β-2 microglobulin; B2M) expression, molecular alterations, and patient outcomes.
Result:
There was expression of PD-L1 in 89 (34.1%) and IDO1 in 74 (28.5%) cases, with co-expression in 49 (18.8%). Both PD-L1 and IDO1 were significantly associated with smoking, aggressive pathologic features, and abundant CD8+ and T-bet+ (Th1 marker) TILs. PD-L1 expression and abundant CD8+ were inversely associated with a loss of B2M membranous expression (p=0.002 and p<0.001, respectively). Compared to PD-L1+/IDO1+ and PD-L1+ only cases, significantly fewer IDO1+ only cases had abundant CD8+ and T-bet+ TILs (p<0.001, respectively). PD-L1 expression was significantly associated with EGFR wild-type (p<0.001) and KRAS mutants (p=0.021), whereas there was no difference in IDO1 expression between different molecular alterations. As for survival, PD-L1 was significantly associated with decreased progression-free (PFS) and overall survival (OS), while IDO1 was associated only with decreased OS. Interestingly, there was a significant difference in the 5-year PFS and OS (p=0.004 and 0.038, respectively), where cases without PD-L1 or IDO1 expression had the longest survival, and those with PD-L1 alone had the shortest survival.
Conclusion:
While PD-L1 +/- IDO1 expression is observed in association with B2M expression, CTL/Th1 microenvironments, EGFR wild-type, and KRAS mutations, isolated IDO1 expression does not demonstrate these associations. These results suggest that IDO1 may serve a distinct immunosuppressive role in ADC. Thus, blockade of IDO1 may represent an alternative and/or complementary therapeutic strategy to reactivate anti-tumor immunity. Additional study to examine a larger number of immunoregulatory markers is ongoing.
