TESTING OF ROS1-POSITIVE TUMORS BY IHC DISPLAYS A FISH-POSITIVE SUBGROUP WHICH MIGHT NOT BENEFIT FROM RECENTLY APPROVED DRUG THERAPY

TESTING OF ROS1-POSITIVE TUMORS BY IHC DISPLAYS A FISH-POSITIVE SUBGROUP WHICH MIGHT NOT BENEFIT FROM RECENTLY APPROVED DRUG THERAPY Vanessa Rüsseler,MD Institut of Pathologie Uniklinik Köln

Disclosure No conflict of interest

Lung cancer High incidence and mortality rate Main subgroup: - non small cell lung cancer (NSCLC): 80% adenocarcinoma(ac) Treatment : in early stages: surgery in advanced stages: Chemotherapy personalised therapy - Immunotherapy ( PDL-1) - Tyrosinkinaseinhibitor (TKIs) depending on molecular profile Pao W. et al. Nat Med. 2012 approved drugs for NSCLC approved drugs for other tumors

ROS1 ROS proto-oncogene 1 (ROS1) gene, chromosome 6q22.1 ROS1 translocation + fusion with different partners => fusion protein becomes constitutively active => via ERK/AKT/STAT pathways =>proliferation and survival Crizotinib, dual ALK/MET tyrosine kinase inhibitor, recently approved by the FDA for treatment of advanced stages of ROS1-positive NSCLC Current gold standard for detecting : FISH (fluorescence-in-situ-hybridization) - Normal: two fusion signals (yellow) - Translocation: 1 fusion and one seperate green/red = BA or 1 fusion and one /many extra green = EG N BA EG

ROS1 (D4D6 ) Rabbit mab Comparison ROS1-FISH-pattern vs IHC 20 ROS1-positive tumor-samples (FFPE) 10 BA 10 EG ROS-1 negativ ROS-1 positiv (1+) ROS-1 positiv (2+) ROS-1 positiv (3+)

Results: BA -FISH 2 4 6 8 3 5 7 9

Results: EG -FISH I III V VII II IV VI X

Results 10 cases break-apart-pattern(ba) 10 cases with extra-green-signals(eg) nr. organ FISH IHC 1 lung-ac 70% BA 19% EG positive 2 lung-ac 30% BA 30% EG positive 3 lung-ac 85% BA 10% EG positive 4 lung-ac 54% BA 29% EG positive 5 lung-ac 38% BA 9% EG positive 6 lung-ac 33% BA 5% EG positive 7 lung-ac 75% BA 12% EG positive 8 lung-ac 22% BA 13% EG positive 9 lung-ac 90% BA + biallelic positive 10 lung-ac 82% BA positive nr. organ FISH IHC I lung-ac 79% EG 1%BA negative II carcinoma NOS 90% EG 2%BA negative III lung-ac 85% EG 5%BA negative IV myxoid sarkoma 95% EG negative V lung-ac 95% EG negative VI vagina-ac 95% EG + amplification negative VII lung-ac 48% EG negative VIII lung-ac 95%EG negative IX lung-ac 70% EG positive X lung-ac 90% EG 5% BA positive

Conclusion ROS1-positive tumors presenting EG in FISH seldom seem be able to produce a stable protein expression detectable by IHC => no benefit from a Crizotinib-therapy, as in most cases the drug target is simply not present? But to really understand the biological background of this special subgroup more detailed investigations need to be done.

Thanks Questions?

Literature + AB (1) GLOBOCAN 2018, Graph production: Cancer Today, (http://gco.iarc.fr/today) International Agency for Research on Cancer 2018 (1) Travis WD et al.: The 2015 World Health Organization Classification of Lung Tumors - Impact of Genetic, Clinical and Radiologic Advances Since the 2004 Classification. JTO 2015 Volume 10, Issue 9, pp1243 1260 (2) Pao W, Hutchinson KE. Chipping away at the lung cancer genome. Nat Med. 2012 Mar 6;18(3):349-51 (3) Lovly C., L. Horn, W. Pao. 2016. Molecular Profiling of Lung Cancer. My Cancer Genome https://www.mycancergenome.org/content/disease/lung-cancer/ (Updated March 28). (4) Lukas Bubendorf et al.: Testing for ROS1 in non-small cell lung cancer: a review with recommendations. Virchows Arch. 2016; 469(5): 489 503. (5) Magda Stumpfova, and Pasi A. Jänne Clin Cancer Res 2012;18:4222-4224 (1) FISH: Zytovision: ZytoLight SPEC ROS1 Dual Color Break Apart Probe (2) IHC: Cell Signaling Technology : ROS1 (D4D6 ) Rabbit mab #3287

Comparison ROS-1+pattern vs IHC Normal=2 fusion signals BA= 1 fusion signal 1seperate green/red EG= 1 fusion signal 1/more seperate green ROS-1 negativ ROS-1 positiv (1+) ROS-1 positiv (2+) ROS-1 positiv (2+)

Estimated age-standardized rates (World) (incidence and mortality), both sexes, More developed regions in 2012 Data source: GLOBOCAN 2012 Graph production: Cancer Today (http://gco.iarc.fr/today) International Agency for Research on Cancer 2016

Estimated number of incidence cases, both sexes, More developed regions (top 10 cancer sites) in 2012 Data source: GLOBOCAN 2012 Graph production: Cancer Today (http://gco.iarc.fr/today) International Agency for Research on Cancer 2016

Estimated number of deaths, both sexes, More developed regions (top 10 cancer sites) in 2012 Data source: GLOBOCAN 2012 Graph production: Cancer Today (http://gco.iarc.fr/today) International Agency for Research on Cancer 2016

Magda Stumpfova, and Pasi A. Jänne Clin Cancer Res 2012;18:4222-4224