Biology of Multiple Endocrine
Neoplasia
Douglas W. Ball, M.D.
Associate Professor of Medicine and Oncology
Johns Hopkins University School of Medicine
September 21, 2009
University of Maryland
MEN2
MEN1
C-Cells MEN2
Follicular Cells MEN1
MEN2
MEN1 MEN1
MEN2
MEN1 MEN1
MEN1
MEN2
MEN2
MEN1 MEN1
MEN1
MEN2
MEN1
MEN2
MEN1 MEN1
MEN1
MEN2
MEN1
MEN2
MEN1
MEN2
MEN1 MEN1
MEN1
MEN2
MEN1
Medulla MEN2
Cortex MEN1
MEN2
MEN1 MEN1
MEN1
MEN2
MEN1
MEN2
MEN1
MEN1
Multiple Endocrine Neoplasia Syndromes
Two distinct syndromes:
MEN1 and MEN2
Both syndromes:
Autosomal dominant inheritance of
multiple endocrine tumors
DNA-based diagnosis of pre-symptomatic patients
MEN1: Inactivation of tumor suppressor MENIN
MEN2: Activation of Ret proto-oncogene
MEN1
Clinical Manifestations
3 P’s: Parathyroid, pancreas, pituitary
Cardinal lesion: parathyroid adenomas
>90% have hyperpara by age 50
GI tumors (50%)
gastrinoma (40%), carcinoid (10%), insulinoma (10%),
glucagon , VIP, somatostatin, “non-secretory”
Pituitary tumors (30%)
prolactinoma (20%), non-secretory, GH (5%),
ACTH (2%)
MEN1:
Additional tumors
Adrenocortical adenomas (25%)
Thyroid follicular adenomas (15%)
Lipomas (30%)
Angiofibromas
Thymic carcinoids (2%)
Bronchial carcinoid (2%)
MEN1:
Molecular Genetics
•Mutations in tumor suppressor gene MENIN at
11q13 in >80% of families
•(>400 independent mutations identified)
•No genotype-phenotype correlations known
•Loss of MENIN in sporadic parathyroid
adenomas, bronchial carcinoids
•Nuclear protein, function controversial
MENIN Structure
• No homology to known proteins other than
three NLS
• Multiple protein interacting domains
MENIN Structure
Mutations I-IX,
collectively 20%
Gene
Protein
Interactions
Other interactions: MLL, ERa, GFAP, vimentin, Smad1/5, others
Lemos and Thakker., Hum Mutation. 29,22-32,2008
MENIN Function
• Implicated in regulating transcription,
proliferation, apoptosis, genome stability
• Functions in a histone methyltrasferase
complex containing MLL A. Yokoyama et al., Mol.
Cell. Biol. 24, 5639 (2004).
• MLL promotes trimethylation of H3K4,
transcriptionally active mark
• Results in up-regulation of p27 and p18
Physiologic Role of MENIN
• Menin down-regulation allows
pancreatic islet hyperplasia during
pregnancy SK Karnik et al., Science. 2007 Nov
2;318(5851):806-9
• Menin gene is transcriptionally
repressed downstream of prolactin
• Menin attenuation also seen in
pancreatic islet response to obesity
MENIN regulation of parathyroid
glands?
• Menin mRNA down-regulated in MEN1-
associated parathyroid tumors, but up-
regulated in primary and secondary
hyperparathyroidism Bhuiyan et al., J Clin
Endocrinol Metab 2000
MENIN as a tumor suppressor
Menin +/- mice:
• 9 months: pancreatic islet hyperplasia
and insulinoma, parathyroid adenomas
• 16 months: larger, more numerous
tumors involving pancreatic islets,
parathyroids, thyroid, adrenal cortex,
and pituitary
• LOH of other allele
JS Crabtree et al.., Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):1118-23.
Why does MENIN mutation result
in endocrine tumors?
• Menin gene expression ubiquitous
• Possible tissue-specific combinatorial
effects?
• Possible unique dependency of
endocrine tissues for transcriptional
actions of Menin?
MEN 2:
Clinical Overview
MEN 2A
Medullary Thyroid Cancer (>90% by age 40)
Pheochromocytoma (50%)
Hyperparathyroidism (15%)
MEN 2B
Medullary Thyroid Cancer
Pheochromocytoma
GI ganglioneuromatosis
Marfanoid body habitus
Familial MTC - FMTC
MEN2:
Molecular Genetics
•Activating mutations in Ret receptor tyrosine
kinase
•Functions as a dominant proto-oncogene
•>95% of families have mutations in 6 exons
•Strong genotype-phenotype correlations
•Acquired Ret mutations in 40-50% sporadic MTC
Activating Ret gene mutations cause MEN 2
•Limited number of mutations aid molecular diagnosis
•Germline Ret testing now standard of care for MTC patients
•Ret: a key target for MTC therapy
Exon 10 11 13 14 15 16
Codon 611 620
609 634
618 634 918
891
768 804 883 918
Cys TM Kinase
Aggressive cases MEN 2A Aggressive cases MEN 2B
Somatic mutation in 30-50%
of sporadic MTC tumors
Ret Protein
Castellone and Santoro Endocrinol Metab Clin North Am. 2008; 37:363-74
Ret Signaling
GDNFR a1-4
Ichihara, Murakumo, Takahashi. Cancer Lett 2004
Ret Signaling
GDNFR a1-4
Ichihara, Murakumo, Takahashi. Cancer Lett 2004
Ret Signaling
Y1062F Knock-in
Ichihara, Murakumo, Takahashi. Cancer Lett 2004
Jijiwa, MCB 2004
Transgenic Ret mutations mimic MEN 2
• Calcitonin promoter - Ret M918T: MTC @
20-22 months Acton Oncogene 2000
• Calcitonin promoter- Ret C634R: MTC and
follicular thyroid tumors Reynolds Oncogene 2001
• p18 knockout strongly promotes MTC in
mice bearing Ret M918T VanVeelen Can Res 2008
Transgenic Ret mutations mimic MEN 2
• Calcitonin promoter- Ret M918T: MTC @
20-22 months Acton Oncogene 2000
• Calcitonin promoter- Ret C6349R: MTC
and follicular thyroid tumors Reynolds Oncogene 2001
• p18 knockout strongly promotes MTC in
mice bearing Ret M918T VanVeelen Can Res 2008
• Ret M918T knock-in: C-cell hyperplasia
and pheochromocytoma Smith-Hicks Embo J 2000
Drosophila screen for pathways
interacting with Ret
WT MEN 2B-enhanced MEN 2B MEN 2B-suppressed
• Ras, src, and jnk pathways modify Ret MEN
2B eye phenotype Read Genetics 2005
• Vandetanib (tyrosine kinase inhibitor) inhibits
eye phenotype Vidal Cancer Res 2005
Ret inhibition: Proof of principle in
MTC
• Dominant negative form of Ret causes
apoptosis and growth inhibition in MTC
cells bearing activated mutant Ret C634W
(Drosten, 2004)
• Neutralizing antibodies to Ret pY1062
also inhibit growth (Salvatore, 2000)
Risk Stratification using Ret
status: Familial MTC
•Level 3 mutations: Codons 883, 918, or 922 highest risk
•Level 2 mutations: Codons 611, 618, 620, or 634 high risk
•Level 1 mutations: Codons 609, 768, 790, 791 804, and 891 least
high risk
Brandi, JCEM 2001
Risk Stratification using Ret
status: Sporadic MTC
•Somatic mutation at 918 confers adverse prognosis for
metastasis-free and overall survival:
Schilling Int J Cancer, 2001
Ret inhibitors usually cytostatic in cell culture
Strock et al. Cancer Res 2003
Irinotecan + Ret inhibitor in MTC:
Xenograft data
Strock, JCEM 2006
Clinical response to XL184-
a ret-VEGF-met inhibitor
Calcitonin levels decline in MTC patients
treated with TKI’s targeting ret
a) 100
100
Patient
80
80 1001
CTN change from baseline (%)
1002
CTN change from baseline (%)
60
60 1013
3001
40
40 7002
20
20
0
0
-20
-20
-40
-40
-60
-60
-80
-80
-100
-100
1 12
1 40
1 68
1 96
2 24
2 52
2 80
3 08
3 36
3 64
3 92
4 20
4 48
4 76
5 04
5 32
5 60
5 88
6 16
6 44
6 72
7 00
7 28
7 56
7 84
14
28
42
56
84
BL
Protoc ol scheduled visit (days)
)
Protocol scheduled visit (days
Responders to Vandetanib
Wells, et al. ASCO 2007
Take home messages
• MEN1 and MEN2 are non-overlapping
syndromes with unique molecular etiologies
• MEN1-- tumor suppressor with LOF mutations
• MEN 2-- proto-oncogene with GOF mutations
• Ret is both a key diagnostic marker and
therapeutic target for MEN 2 and MTC
• Menin less useful diagnostically and
therapeutically in MEN 1, to date