TERAPEUTIC CONSEQUENCES FROM MOLECOLAR BIOLOGY FOR GIST PATIENTS AFFECTED BY NEUROFIBROMATOSIS TYPE 1 Mussi C, Schildhaus HU, Gronchi A, Wardelmann E,

TERAPEUTIC CONSEQUENCES TERAPEUTIC CONSEQUENCES FROM MOLECOLAR BIOLOGY FOR FROM MOLECOLAR BIOLOGY FOR

GIST PATIENTS AFFECTED BY GIST PATIENTS AFFECTED BY NEUROFIBROMATOSIS TYPE 1NEUROFIBROMATOSIS TYPE 1

Mussi C, Schildhaus HU, Gronchi A, Wardelmann E, Hohenberger P

CTOS-Seattle, November 2007

supported by Conticanet

Mannheim University Hospital, Germany

Bonn University Hospital, Germany

Istituto Nazionale Tumori, Italy

BACKGROUNDBACKGROUND

• Patients affected by Neurofibromatosis type 1 have an

increased risk of GIST developing

• NF-1 associated GISTs seem to be wild type for

KIT/PDGFRA mutations

• This subset of GIST has likely a different oncogenic

molecular mechanism

• Lack of data on imatinib and other tyrosine kinases

inhibitors activity in this different setting

QUESTIONSQUESTIONS

• Should these patients enrolled in the ongoing

trials of imatinib?

• Should this decision taken on the basis of the

molecular analysis?

PATIENTSPATIENTS

28 PATIENTS OPERATED

• 13 MALES

• 15 FEMALES

• M:F=0,87:1

• Median age 57 (range 28-72)

DIAGNOSISDIAGNOSIS

NEUROFIBROMATOSIS TYPE 1

>2 following criteria:• > 6 cafe-au-lait macules (>5mm before puberty, >15 mm after)

• skin-fold freckles (groin, axilla, neck base)

• > neurofibromas (1 plexiform)

• skeletal dysplasia (orbital or tibial)

• Lisch nodules (>2 iris amartomas)

• optic glioma

• family history

DIAGNOSISDIAGNOSIS

GIST

• The diagnosis was confirmed histologically in terms

of morphology and immunophenotyping

• Seven tumors were reclassified as GIST after

pathologic review

• 2 MPNST

• 1 Schwannoma, 1 Neurofibroma

• 2 Leiomyosarcoma

• 1 Leiomyoma

All tumors were sympthomatic except one

PRESENTATIONPRESENTATIONPRESENT SERIES SPORADIC GIST

• Age 57 yrs (28-72)

• M:F=0,87:1

• LOCALIZED 82%

• METASTATIC 18%

• RISK STRATIFICATION

•High 30,5%

•Intermediate 39%

•Low/very low 30,5%

• Age 60 yrs (20-80)

• M:F=1,3:1

• LOCALIZED 50-85%

• METASTATIC 15-50%

• RISK STRATIFICATION

•High 23-35%

•Intermediate 20%

•Low/very low 45%

70%

SITESITEPRESENT SERIESPRESENT SERIES SPORADIC GISTSPORADIC GIST

25%14%

68%

Other: 11%

60%

30%

Other: 10%

7%

NUMBERS OF TUMORSNUMBERS OF TUMORS

PRESENT SERIES SPORADIC GIST

MULTIPLE TUMORSMULTIPLE TUMORS

43 % Occasional

IMMUNOCHEMISTRYIMMUNOCHEMISTRY

PRESENT SERIESPRESENT SERIES SPORADIC GISTSPORADIC GIST

• CD 117 pos 100%

• CD 34 pos 86%

• S-100 pos 19%

• Actine pos 24%

• PDGFRA pos 37,5%

• BCL-2 pos 43%

• CD 117 pos 95%

• CD 34 pos 70%

• S-100 pos 10%

• Actine pos 25%

• PDGFRA pos 70%

• BCL-2 pos 20-93%

PATHOLOGYPATHOLOGY

PRESENT SERIESPRESENT SERIES SPORADIC GISTSPORADIC GIST

• Spindle cell 75%

• Epithelioid 15%

• Mixed 10%

• Skenoid fiber 33%

• Associated Cajal

cell hyperplasia 21%

• Spindle cell 38-77%

• Epithelioid 8-38%

• Mixed 14-23%

• Skenoid fiber 34%

MOLECULAR ANALYSISMOLECULAR ANALYSIS

• c-KIT exons 9, 11,13,17

• PDGFRA exon 12, 14, 18

DNA extracted from paraffin embedded DNA extracted from paraffin embedded microdissected sections was sequenced for:microdissected sections was sequenced for:

25 PTS

MOLECULAR ANALYSISMOLECULAR ANALYSIS

• exon 11 (V560del)

• exon 9 (A504_Y505)

• Exon 18 (D842V)

PRIMARY MUTATIONSPRIMARY MUTATIONS

MOLECULAR ANALYSISMOLECULAR ANALYSIS

Exon 17 D820N mutation in metastatic

lesions after gleevec therapy

SECONDARY MUTATIONSECONDARY MUTATION

MOLECULAR ANALYSISMOLECULAR ANALYSIS Series N° of Pts KIT mut PDGFRA mut NF1 mut

Kinoshita, 2004 7 None None 2/3 pts Cheng, 2004 3 1 ex 11 None NS Anderson, 2005 12 None None NS Takazawa, 2005 9 2 ex 11, 1 ex 13 1 ex 12, 1 ex 18 NS Yantiss, 2005 3 1 ex 11 None NS Miettinen, 2006 15 None None NS Maertens, 2006 3 2 polimorphisms 5 silents 3/3 pts Nemoto, 2006 1 None None 1/1 pts Guillaud, 2006 1 None None NS Lee, 2006 1 None None NS Steward, 2007 2 None None 1/2 pts Kang, 2007 5 None None NS Present series 25 1 ex 11, 1 ex 9 1 ex 18 NS ________________________________________________________________

10 KIT-PDGFRA Mutations/ 90 patients analysed = 11, 1%

MOLECULAR ANALYSISMOLECULAR ANALYSISSPORADIC GISTNF-1 ASSOCIATED GIST

• KIT Mutations 7,8%

•Exon 11 5,6%

•Exon 9 1,1%

•Exon 13 1,1%

•Exon 17 0%

• PDGFRA Mutations 3,3%

•Exon 12 1,1%

•Exon 14 0%

•Exon 18 2,2%

• KIT Mutations 80%

•Exon 11 67,5%

•Exon 9 11%

•Exon 13 0,9%

•Exon 17 0,5%

• PDGFRA Mutations 7,5%

•Exon 12 0,9%

•Exon 14 0,3%

•Exon 18 6,3%

CLINICAL OUTCOMECLINICAL OUTCOME

• Prospective periodical assessment

• Five patients had other maligniancies

(2 gastrointestinal carcinoid; 1 cutaneous basalioma; 1 brain meningioma; 2 uterus carcinoma; 1 adrenal pheocromocytoma; 1 breast cancer)

• 8 patients develloped local recurrence or metastasis

• Six patients died of disease

SURVIVALSURVIVAL

• 5-year EFS 46,9% (median 48 months)

• 5-year DSS 54,3% (median NR)

Post-event median survival 34 months

Multiple tumors had a better outcome

IMATINIB THERAPY: resectable GISTIMATINIB THERAPY: resectable GISTPts Primary Setting Trial Imatinib EFS Status

----------------------------------------------------------------------------------1 Localized postop. EORTC 400mg/d 11 NED

62024

2 Localized postop. SSGVIII/ 400mg/d 8 NED

AIO

3 Syncronous postop. / 400mg/d 22 NED resectable metastasis

4 Multiple postop. / 400mg/d 45 NED recurrent tumors

5 Localized postop. EORTC Control 14 NED 62024 Arm

IMATINIB THERAPY: advanced GISTIMATINIB THERAPY: advanced GIST

Pts Site Risk Metastasis Molecular Resp. Post IM Status (prim.) analysis Surv

(EORTC 62005 trial)

-----------------------------------------------------------------------------------

1 ExGI H liver, WT PD 22 DOD peritoneal

2 Small H liver, WT PD 19 DOD Bowel peritoneal

3 Stomach I liver, EX 18 SD 22 DOD peritoneal

4 Small H peritoneal WT prim; PD 10 DOD Bowel Secondary

ex 17-----------------------------------------------------------------------------------Median survival after imatinib onset 21 months

IMATINIB THERAPY: IMATINIB THERAPY: ex vivoex vivo

• Kit phosporylation is stem cell factor dependent

• The MAPK pathway is more active then in sporadic GIST

• JAK-STAT 3 and P13K-AKT are less active then in sporadic GIST

• The MAPK phosporylation cannot be complete shut down by imatinb and the effect is not dose dependent

IMATINIB THERAPY: IMATINIB THERAPY: neurofibrin neurofibrin deficit is associated with high deficit is associated with high

levels of levels of Kit expressionKit expression

IMATINIB THERAPY: IMATINIB THERAPY: in vivoin vivo

IMATINIB THERAPY: IMATINIB THERAPY: in vivoin vivo

……IN BRIEFIN BRIEF

• The incidence of GIST in NF-1 is unknown, but

symptomatic tumors are often high or intermediate

risk (70%)

• Most tumors are wild type for KIT/PDGFRA

mutations (89%)

• The oncogenic mechanism causing the MAPK

pathway activation and KIT overexpression is related

to the neurofibrin deficit

CONCLUSIONSCONCLUSIONS

The molecular analysis is always raccomended

• to individuate sporadic mutation

• to clarify the prognostic meaning of mutations in

this subset of GIST

CONCLUSIONSCONCLUSIONS

Further studies are necessary to clarify the

effecacy of IM and other inhibitors of tyrosine

kinases in this setting

CONCLUSIONSCONCLUSIONS

• Localized wild type GIST should not be

elegible for adjuvant trials

• The molecular analysis should be done before

the enrollement

CONCLUSIONSCONCLUSIONS

• Local advanced GIST enrolled in trials of

preoperative imatinib should be carefully

surveilled

CONCLUSIONSCONCLUSIONS

• Metastatic GIST could benefit from

imatinib treatment

• Sunitinib could be the first alternative in

non responder tumors

CONCLUSIONSCONCLUSIONS

The future treatent of this subset of

GIST is likely dependent from further

investigations of the molecular pathways

activated by neurofibrin as new

molecular targets

THANKS!THANKS!

….chiara.mussi@chir.ma.uni-heidelberg.de