Bersagli molecolari nel melanoma

Transcription

1 Bersagli molecolari nel melanoma Giuseppe Palmieri - Unit of Cancer Genetics Institute of Biomolecular Chemistry, CNR, Sassari

2 Essential alterations in malignant cells Hanahan & Weinberg, Cell 2000

3 Essential alterations in malignant cells Hanahan & Weinberg, Cell 2011

4 Main pathways in melanomagenesis Fecher, JCO 2007; Palmieri, JCMM 2007; Palmieri, JTM 2009; Palmieri, Skin Cancer Book 2012

5 Role of BRAF gene in melanoma Nevi harbour BRAF mutations (mostly ) at quite same prevalence of melanoma BRAF mutations are necessary but not sufficient for MM development Pollock, Nature Genet 33, 2003; Casula, J.Clin.Oncol 22, 2004; Sharma, Cancer Res 65, 2005

6 The main road to melanoma Melanocytic proliferation Melanoma development Melanoma progression BRAF activation impairment of: 9p21 allelic deletions p16-rb pathway p14-p53 pathway AKT overexpression CyclinD1 amplification PTEN loss/inactivation Miller and Mihm, NEJM 2006; Palmieri, JCO 2007; Palmieri, JCMM 2007 loss of p16 CDKN2A MITF amplification Low expression of melanoma markers regulated by MITF

7 The Melanomas non CSD CSD Acral Mucosal Curtin, NEJM 2005

8 The Melanomas 50.0% KIT RAS BRAF 0.0% nocsd CSD acral mucosal Curtin, NEJM 2005

9 Incidence of key driver oncogenes in melanoma BRAF ~ 50% NRAS ~ 15% ckit ~ 1% Primarily mucosal and acral lentiginous GNAQ/GNA11 ~ 1% Almost exclusively uveal Nikolaou, J Invest Dermatol Smalley, Semin Oncol. 2012

10 germline somatic BRAF/NRAS mutations in MM: our experience BRAF NRAS cell lines 18/32 (56%) 4/32 (12%) metastases 153/298 (51%) 34/216 (16%) primary MM 223/451 (49%) 46/312 (15%) peripheral blood 3*/897 (0.3%) not tested *No exon 15 mutation Casula, JCO EJC 2007; Colombino, JCO JTM 2013

11 metastases BRAF/NRAS mutations in MM metastasis BRAF NRAS Lymph node 78/151 (52%) 15/102 (15%) Visceral 25/47 (53%) 4/30 (13%) Liver 16/30 (53%) 3/22 (14%) Lung 9/17 (53%) 1/8 (12%) Skin 29/54 (54%) 5/38 (13%) Brain 21/46 (46%) 10/46 (22%) TOTAL 153/298 (51%) 34/216 (16%) Colombino JTM 2013

12 BRAF/NRAS mutations in primary MM NRAS mutations: 46/312 (15%) BRAF mutations: 223/451 (49%) Sardinian patients NRAS mutations: 2/105 (2%) BRAF mutations: 109/178 (61%) Non-Sardinian patients NRAS mutations: 44/207 (21%) BRAF mutations: 114/273 (42%) Colombino JTM 2013

13 Patients' geographical origin may account for different mutation rates in pathogenetic cancer genes

14 Pathogenetic mutations in MM No overlap between KIT mutations NRAS mutations BRAF mutations Beadling 2008; Ascida 2009; Colombino 2012 and 2013

15 Advanced melanoma: different strategies according to mutational status BRAF mut NRAS mut KIT mut BRAF NRAS KIT Modified from Ascierto

16 Targeting BRAF

17 BRAF inhibitors only inhibit in the context of B-RAF mutation NRAS BRAF CRAF MEK ERK Heidorn, Cell Poulikakos, Nature Hatzivassiliou, Nature 2010

18 BRAF inhibitors only inhibit in the context of B-RAF mutation NRAS RAS-GTP BRAF CRAF BRAF mut CRAF CRAF MEK ERK MEK MEK ERK ERK Heidorn, Cell Poulikakos, Nature Hatzivassiliou, Nature 2010

19 Objective tumor responses with vemurafenib Intrinsic resistance N Engl J Med 2012

20 Progression-free survival (%) Progression-free survival No. of patients in follow up Dacarbazine Vemurafenib 0 Hazard Ratio 0.26 (95% CI; ) Log-rank P< Median 1.6 mos Dacarbazine (N=274) Vemurafenib (N=275) Median 5.3 mos Months Acquired resistance N Engl J Med 2012

21 Intrinsic resistance Alterations predicted to cause resistance in pre-treatment sample Acquired resistance Alterations in the resistant sample at undetectable or subclonal level prior to therapy

22 Main mechanisms of resistance

23 Intrinsic BRAF resistance

24 Mutation patterns by NGS approaches Krauthammer, Nat Genet 2012

25 Acquired BRAF resistance

26 Acquired BRAF resistance

27 Resistance to target therapies Second biopsy?

28 Additional levels of complexity

29 BRAF multiclonality G/T Lin et al., J Natl Cancer Inst. 2009

30 Intratumor heterogeneity of BRAF Yancovitz, PLoS ONE 2012

31 Do prevalence of main mutations vary during the disease progression phases and among different types of metastasis?

32 BRAF/NRAS mutations among primary tumors and metastases in MM patients Tissue types Lymph node metastasis Visceral metastasis Consistency secondary/primary melanomas 91/101 (90%) 29/32 (91%) Primary tumor Metastasis BRAF NRAS BRAF NRAS V600K not tested not tested L597R not tested not tested

33 BRAF/NRAS mutations among primary tumors and metastases in MM patients Tissue types Brain metastasis Skin metastasis Consistency secondary/primary melanomas 18/22 (82%) 34/48 (71%) Primary tumor Metastasis BRAF NRAS BRAF NRAS Q61R Q61R Q61R not tested not tested Q61L Q61L Q61R Q61L not tested not tested

34 Example of expression plots for lower extremity in-transit melanomas in the same patient Augustine, Mol Cancer Ther 2010

35 Molecular classification of all tumor lesions in MM patients?

36 Molecular analysis in MM patient flow DISTINCT SETS OF GENETIC ALTERATIONS ~5% Uveal GNAQ mut + GNA11 mut + ckit mut-ampl + BAP1 mut ~5% Mucosal ckit mut + ckit ampl + CCND1 ampl + CDK4 ampl ~10% ~15% ~60% Acral CSD Non-CSD NRAS mut + BRAF mut + ckit mut-ampl + BAP1 mut + CCND1 ampl + CDK4 ampl NRAS mut + BRAF mut + ckit mut + ckit amplification + CCND1 ampl + CDK4 ampl NRAS mut + BRAF mut + BAP1 mut ~5% Conjuntival ckit mut + ckit ampl

37 new genes by next-generation sequencing? Whole genome sequencing of melanomas and matched germline DNA samples

38 Sardinian CNR SS University SS ASL1 SS Businco CA Non Sardinian Casula, Colombino, Manca, Palomba, Pisano, Rozzo, Sini Cossu, Lissia, Satta, Tanda Budroni, Contu, Scotto Bruder, Muggiano INT Pascale NA Ascierto, Ayala, Botti, Caracò, Mozzillo University SA University GE University FI University NA AOU Siena IDI Roma IRCCS Meldola Acknowledgements Rubino Bianchi-Scarrà, Ghiorzo De Giorgi, Massi Staibano Maio D Atri, Pagani Stanganelli