위장관종양의표적치료를위한 면역조직화학적및분자병리학적 진단기법 이혜승 분당서울대학교병원병리과

Transcription

1 위장관종양의표적치료를위한 면역조직화학적및분자병리학적 진단기법 이혜승 분당서울대학교병원병리과

2 Contents HER2 testing in gastric cancer - Clinicopathologic significance of HER2 - Practical approach of HER2 testing Resistance to anti-egfr therapy in colorectal cancer Targeted Imatinib therapy for GIST

3 Gene. ERBB2 Official full name: v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 [human] Location: 17q12 This gene encodes a member of the epidermal growth factor receptor family of receptor tyrosine kinases

4 Protein. HER2 Human Epidermal Growth Factor Receptor 2 A protein encoded by the ERBB2 gene Also known as Neu, ErbB-2, CD340 or p185 Normally expressed on the cell surface in a variety of tissue types including breast and gastric epithelium Amplification or over-expression: aggressive types of breast cancer, target of therapy, 30% of breast cancer patients

5 HER2 signaling No ligand binding domain of its own (cannot bind growth factors) Bind tightly to itself and to other ligand-bound EGF receptor family members to form homodimers and heterodimers HER2-HER3 heterodimer: the most active HER signaling dimer Downstream proteins activates cell proliferation and migration Ras/Raf/MAPK PI3K/AKT/mTOR

6 The HER family [1] HER1 (EGFR) [2] HER2 [3] HER3 [4] HER4 extracellular ligand binding domain, transmembrane domain intracellular domain

7

8 HER2 amplification/overexpression 6% to 35% of gastric cancers (about 10%) Relatively greater proportion in the GE junction compared with gastric tumors or in upper third of stomach Intestinal type (vs. diffuse or mixed/anaplastic tumors) J Clin Gastroenterol 2012;46:637

9 Gastric cancer Year Total no. FISH or SISH HER2+ IHC2+ IHC3+ Im et al % 7.1% 8.6% Kim et al (595) 8.6% (4.7%) 8.4% (7.8%) Cho et al % 1.6% 6.6% Terashima et al % 12.2% 9.0% Kim et al % 19.4% 8.5% Lee et al % 14.9% 7.8% Sheng et al % 11.6% 10.2% Bria et al % 3.3% 3.3% Okines et al.* % 10.4% 4.9% 8.2% Esophageal cancer Year Total no. FISH or SISH HER2+ IHC2+ Hu et al % 12% IHC3+ Yoon et al % 16.7% 24% 13% HER2+, IHC 3+ and IHC2+/FISH or SISH+ * EAC and GC by TMA method

10 Patients outcome (I) 35 clinical trials and 9,063 patients from 1991 to 2010 Prognostic factor in 22 trials (14 trials in the east and 8 in the west); related to overall survival, increased risk of lymph node metastases, reduced survival for early-stage disease, recurrent disease, disease progression, poor tumor differentiation, or advanced disease stage Not a prognostic factor in remaining 13 trials; no association between HER2 amplification/overexpression and overall survival, invasion, metastases, or tumor stage J Clin Gastroenterol 2012;46:637

11 Patients outcome (II) Between 1991 and studies (1413 patients): association between HER2 overexpression and worse OS 4 studies (1037 patients): no association From 2009 to the present 11 studies (5869 patients): does not impact the prognosis 6 studies (3199 patients): poor prognostic factor Crit Rev Oncol Hemtol 2013;85:350

12 Crit Rev Oncol Hemtol 2012;82:310

13 TRATUZUMAB Humanized monoclonal antibody that specifically targets the extracellular domain of HER2

14 ToGA study (I) International, randomized, open-label phase III trial in patients with HER2-positive, inoperable advanced or metastatic gastric or GE junction cancer

15 ToGA study (II) By Post-hoc analysis, HER2 positive: IHC3+ or IHC2+/FISH-positive

16 Gastric or gastroesophageal cancer specimen Immunohistochemistry (all) 0/ In situ hybridization Non-amplified Amplified HER2 negative HER2 positive Tratuzumab therapy

17 Regional hegerogeneity of HER2 Definition of heterogeneous HER2 expression: 5~50%, 10~50%, 10~70% Incidence: 10~40% in IHC 3+ cases vs. 60~95% in IHC 2+ cases No difference in the staining pattern between superficial and deep portions of tumor Heterogeneous expression: IHC 2+, diffuse or mixed histologic type, better prognosis than homogeneous expression IHC 3+ ~~ GA by FISH/SISH ~~ homogeneous Ann Surg Oncol 2013;20:S477 Eur J Cancer 2013;49:1448 Ann Surg Oncol 2011;18:2833

18 Regional heterogeneity Eur J Cancer 2013;49:1448

19 Genetic heterogeneity Definition: gene amplification (HER2/CEP17 ratio 2.0) in more than 5% but less than 50% of cancer cells Incidence: 20 (17%) of 117 HER2 amplified EACs, 5 (11.4%) of 44 IHC 2+ GCs EACs: poor histologic grade, polysomy 17, poor prognosis Ann Surg Oncol 2013;20:S477 J Clin Oncol 2012;30:3932

20 Heterogeneous or Discordant HER2 status in gastric cancer Intratumoral HER2 heterogeneity Regional heterogeneity Genetic heterogeneity Discordant HER2 status between primary cancer and related distant metastasis: not uncommon Discordant HER2 status between biopsy and resection specimens: heterogeneity and specimen quality

21 Contents HER2 testing in gastric cancer - Clinicopathologic significance of HER2 - Practical approach of HER2 testing Resistance to anti-egfr therapy in colorectal cancer Targeted Gleevec therapy for GIST

22 ASCO/CAP 2013 recommendations for breast cancer Begin fixation process quickly (time to fixative within 1 hour) Duration of fixation: 6-72 hours in 10% NBF, cytology specimens must be fixed in formalin Gross specimens should be sliced at 5-10 mm intervals. Sections should not be used if cut > 6 weeks earlier (this may vary with primary fixation or storage conditions). Tests should be performed according to standardized analytically validated protocols. Initial test validation/ monitoring of test concordance between methods/ internal and external QA Oct 17, 2013 online and Arch Pathol Lab Med

23 Unique features of HER2 testing in gastric cancer High incidence of tumor heterogeneity Bright-field methodologies are preferred. Screening by immunostaining before ISH <10% positivity should repeat on a different paraffin block if still inconclusive, ISH test should be performed Should perform on both primary and distant metastatic sites Gland-forming intestinal type incomplete, basolateral, or lateral staining + complete membrane staining Applying the breast cancer testing principles and scoring criteria results in underscoring (false negatives in about 50%)

24 Practical guidance on HER2 testing in gastric cancer Preanalytic Specimen type Fixation Tissue processing Tissue sectioning Analytic Assays Control selection Quality assurance Postanalytic Interpretation of results Reporting of results Pathologist Ruschoff et al. Mod Pathol 2012;25: Kim et al. Asia Pac J Clin Oncol. 2014;10:

25 PREANALYTIC Specimen type Surgical resection and biopsies are both accepted Biopsy: better fiixation, but ideally need 6-8 pieces due to heterogeneity Task Force 4-6 pieces acceptable Tissue microarrays: not recommended Second biopsy at metastasis Fixation 10% neutral buffered formalin Preanalytic cold ischemic time: within 20 min of biopsy, within 1 hour of resection, but recommend each laboratory to validate it) Fixation time: 8~72 hours Sections ~4 um or less should be immediately before testing

26 ANALYTIC Validated, commercially available methodologies are recommended for accurate and reliable results Ventana PATHWAY (4B5 clone) DAKO HercepTest Antigen retrieval Automated, temperature-controlled method Controls Both no staining and strong staining (if possible, equivocal) Similar fixation, processing, and paraffin embeddeing technique to the test samples Tissue microarrays

27 Quality Assurance Initial test validation: The initial cases should be analyzed in parallel using both IHC and ISH. The concordance rate should be >90% (equivocal 제외시 ) Validate independently of breast cancer protocols Personnel should be specifically trained in HER2 testing methods and interpretation for gastric cancer. Monitoring of test concordance between methods, positivity rates, and scoring distributions Internal QA program and external proficiency assessment

28 POSTANALYTIC Assessment of HER2 IHC staining Should interpret an INVASIVE AREA of the carcinoma According to IHC scoring system for GASTRIC CANCER Assessment of HER2 gene amplification Selecting assessment area by H&E (intestinal type) and IHC (2+ or 3+) staining 20 adjacent or continuous cells HER2:CEP17 ratio count another 20 cells or score in an alternative area of tissue Report HER2-negative vs. HER2-positive (IHC 3+ or IHC 2+/amplification)

29 HER2 scoring criteria in gastric cancer A cluster of at least 5 positive stained tumor cells

30 Magnification rule IHC 3+ : any membranous staining visible at low magnification. Lateral- or U- shaped membranous staining. IHC 2+ : membranous staining is visible at magnification. Need FISH or SISH. IHC 1+ : visible only with 40 magnification. HER2- negative. Mod Pathol 2012;25:637-50

31 요양급여의적용기준및방법 (HER2 FISH, SISH) 나 590 형광동소교잡반응법 -HER2 유전자및나 591 실버동소교잡반응법 -HER2 유전자 형광동소교잡반응 -HER2 및실버동소교잡반응 -HER2 유전자검사는 trastuzmab 약제투여등을위해실시한다음의경우요양급여를인정함 1. 적응증가. 전이성위암전이성위선암또는위식도접합부선암중 HER2 면역조직화학검사결과 2+ 인경우 2. 인정횟수 가. 최초수술시혹은생검시 1 회인정 나. 암종재발및전이시추가인정 3. 형광동소교잡반응 -HER2 유전자검사와실버동소교잡반응 -HER2 유전자검사의중복산정은인정하지아니함.

32 Optimal patient selection for trastuzumab treatment Clin Cancer Res Feb 23. pii: clincanres [Epub]

33 Recently presented or ongoing studies Lapatinib small molecule inhibitor of EGFR and HER2 binds to the intracellular domain effects on p95her2 LOGiC and TYTAN trial FAIL in gastric cancer patients Pertuzumab inhibit dimerization of HER2 with other HER family members Pertuzumab plus trastuzumab Trastuzumab Emtansine (T-DM1) antibody-drug conjugate consisting of the monoclonal antibody trastuzumab (Herceptin) linked to the cytotoxic agent DM1 DM1 enters cells and destroys them by binding to tubulin

34 HER2 ECD HER2 p95her2

35 Contents HER2 testing in gastric cancer - Clinicopathologic significance of HER2 - Practical approach of HER2 testing Resistance to anti-egfr therapy in CRC - Genetic alterations related to therapy - Practical approach in CRC patients Targeted Imatinib therapy for GIST

36 Anti-EGFR therapy in mcrc humonc.wisc.edu

37 Herreros-Villanueva et al. Clin Chim Acta. 2014

38 Cancer Discov Nov;4(11):

39 Prevalence of genetic alterations - associated with de novo resistance to anti-egfr therapies in mcrc- KRAS amplification BRAF V600E NRAS exon 4 NRAS exon 3 MET amplification HER2 amplification NRAS exon 2 KRAS exon 4 KRAS exon 3 KRAS WT KRAS exon 2 Cancer Discov Nov;4(11):

40 RAS/MAPK pathway regulates cell proliferation RAS mutations lead to: Continuous signaling Unregulated cell proliferation Ineffectiveness of anti- EGFR antibody therapies

41 RAS Intracellular GTPase KRAS (two splice variants), HRAS, NRAS All RAS proteins are highly homologous in structure and function. In each RAS protein, mutations in codons 12, 13, or 61 can cause constitutive activation of downstream pathways. Response rates to anti-egfr treatment: 35~45% related to KRAS codons 12, 13 mutations

42 KRAS mutation test Exon 2 mutation: approximately 35~45% of colorectal cancer Lack of response to Cetuximab and Panitumumab Patients diagnosed with metastatic CRC are routinely screened for KRAS mutations. Several technologies have been compared for developing testing guidelines!

43 Clinical significance of each KRAS mutation c.35g>t (p.g12v): highest frequency of mortality in CRC patients c.34g>c (p.g12r) and c.35g>t (p.g12v): more transforming ability than other KRAS mutations Herreros-Villanueva et al. Clin Chim Acta Loupakis F et al. Br J Cancer. 2009

44 Contents HER2 testing in gastric cancer - Clinicopathologic significance of HER2 - Practical approach of HER2 testing Resistance to anti-egfr therapy in CRC - Genetic alterations related to therapy - Practical approach in CRC patients Targeted Imatinib therapy for GIST

45 KRAS mutation analysis in daily practice Metastatic colorectal cancer patients H&E slide review and tumor marking by pathologist Slide cutting and macrodissection DNA extraction PCR Sequencing Interpretation

46 Physician Patient Critical importance of accurate test results Test results Invalid False-negative False-positive Correct detection Delayed treatment; disease progression Patient not considered for targeted therapy Patient considered for targeted therapy that will not be beneficial Patient considered for targeted therapy; improved clinical outcomes and quality of life Lack of data means physician cannot make informed decision Inaccurate test results prevent physician from optimal clinical decision making Accurate test results enable physician to prescribe optimal clinical treatment

47 Invalid results Poor quality or insufficient amount of human tissue samples

48 Effects of fixation and storage on nucleic acid preservation [1] DNA PCR results according to the duration of formalin fixation due to DNA damage and PCR inhibitors [2] DNA PCR results according to the duration of decalcification -actin SM NC Nam et al. Korean J Pathol. 2014

49 False negative Sensitivity: % of mutants in total extracted gene fragments Sanger sequencing: 10~20% Pyrosequencing: 5% TheraScreen (1%) Cobas (1%) Panagen (1%) mutant vs. wild type

50 % Tumor content necrosis mucin pool

51 Tumor heterogeneity Center vs. periphery (KRAS): 33/75 (44%) Center1 vs. center2 (KRAS): 23/75 (34.8%) Kosmidou et al. Hum Mutat. 2014

52 False positive Effect of formalin fixation Cross reaction Misinterpretation of noise bands

53 Detection methods for gene mutation Sanger sequencing Commercial testing kits (In Vito Diagnostics) Commercial testing kits (Research Use Only) Pyrosequencing Next-generation sequencing Laboratory-developed tests real-time PCR, digital PCR methods for enrichment of mutants

54 Sanger sequencing Previously the gold standard methodology Advantages Cheapest, widely available Identify specific mutations (new and rare mutation) Detects all mutations (ex. KIT ) 대부분행위비급여목록에포함 : 유전자돌연변이검사 ( 염기서열 )

55 Workflow of sanger sequencing

56 Data analysis of sanger sequencing GGTGGC : no mutation GATGGC : missense mutation c.35g>a, p.g12d

57 Sanger sequencing Disadvantages Low sensitivity: 10% (if heterozygous, 20% of tumor cells is needed) Multisteps and time consuming Subjective interpretation No standardization or QC protocol Decreased use for predicting response to targeted therapy

58 Commercial kits Asuragen, DxS TheraScreen KRAS mutation detection kit, EntroGen, Roche COBAS, TrimGen Mutector II KRAS kit, and ViennaLab With real-time PCR method: a reliable and feasible method Small intra- and inter-lot deviations and good concordance Advantages high sensitivity fast easy data interpretation a closed-tube one-step process Disadvantages high cost per samples high DNA input requirements Cannot detect all mutations

59 Commercial kits 장점 검사실 setting 이쉽다 적은인력으로가능 빠르다 민감도가높다 검사방법과결과가재현성이높고정도관리가용이 조직이작거나오래된경우재검이적다 문제나오류발생시회사와상의 단점 행위비급여목록, 신의료기술, IVD 시약인지등을확인해야한다 새로운유전자검사를 setting 하기어렵다 시약값이비싸다 기기를새로구입해야할수도있다 어떤돌연변이인지알수없다 문제나오류발생시직접바꿀수없음

60 Workflow of Commercial kits Simple: negative or positive

61 Herreros-Villanueva et al. Clin Chim Acta KRAS testing with real-time PCR TheraScreen COBAS PNA-clamp assay Principles for the mutant analysis Scorpions and ARMS technologies TaqMelt PCR assay Using peptide nucleic acid (PNA) Advantages High sensitivity Fast Closed-tube One-step process FDA approved High sensitivity Fast Closed-tube One-step process IVD High sensitivity Low cost Disadvantages High cost Detects only 7 mutations High amounts of DNA input High cost High amounts of DNA input Cannot identify specific mutation Cannot identify specific mutation Sensitivity 1% mutant alleles 1% 0.1% Number of KRAS mutation detected 6 in codon 12 1 in codon in codons 12,13,61 7~13 in codons 12,13,61* *depending on the kit (Panagen: 7 in codon 12, 13)

62 Pyrosequencing Compared to sanger sequencing More sensitive (5%) Simple and faster Less complex data analysis Can only sequence a short length Cannot detect all mutations (can detect known mutations)

63 Pyrosequencing Compared to commercial kits Single PCR primer pair and sequencing primer for codon 12 and 13 Detect specific mutations Pyrosequencing data analysis can be complex and challenging Less sensitive Requires a costly instrument, expensive reagents, and consumable Not be affordable for small-to medium-sized medical laboratories

64 Workflow of pyrosequencing DNA extraction PCR Sample prep Pyrosequencing ~ 2h ~ 15 min ~ min PyroMark PCR Kit PyroMark OneStep RT-PCR Kit PyroMark Q24/Q96 Vacuum Prep Workstation PyroMark Q24 PyroMark Q96ID PyroMark Q96MD

65 Data analysis of pyrosequencing GATGGC : missense mutation c.35g>a, p.g12d

66 Next-generation sequencing (NGS) KRAS mutations: 30-40% of nonresponsiveness to antibody treatment Other genes mutations of NRAS, BRAF, PIK3CA Loss of PTEN or AKT protein Insufficient evidence to recommend or discourage testing

67 Next-generation sequencing (NGS) Advantage High throughput method for fully sequencing a large number of genes Disadvantage Large amount of bioinformatics data challenges for data processing Expensive, long run time, a short read length, complex sample preparation and amplification, complicated data analysis? FFPE 진료비청구불가

68 NRAS mutation Sanger sequencing, pyrosequencing Commercial kits Cobas: Research Use Only 파나진 : 없음 Qiagen: pyrosequencing based only

69 BRAF V600E Aim Predict resistance of anti-egfr therapy Predict poor prognosis Exclude Lynch Syndrome in MSI-H CRCs Methods Sanger sequencing Pyrosequencing Commercial kits Restriction fragment length polymorphism Immunohistochemistry Am J Surg Pathol. 2013;37:

70 EGFR IHC

71 Contents HER2 testing in gastric cancer - Clinicopathologic significance of HER2 - Practical approach of HER2 testing Resistance to anti-egfr therapy in CRC - Genetic alterations related to therapy - Practical approach in CRC patients Targeted Imatinib therapy for GIST

72 Targeted Imatinib therapy for gastrointestinal stromal tumor patients KIT and PDGFRA mutation in GIST Sanger sequencing KIT exon 11, 9, 13, 17 (85%), PDGFRA (10%) Mutually exclusive KIT and PDGFRA mutations Imatinib : small molecule tyrosine kinase inhibitors blocking c- KIT and PDGFRA signaling Inferior response to imatinib KIT D816V (exon 17) KIT exon 9 mutation PDGFRA exon 18 D842V mutation Lack of detectable KIT or PDGFRA mutations

73 경청해주셔서감사합니다