genetic cancer syndromes-scientific background & clinical implications asher salmon m.d, ph.d...

Genetic Cancer Syndromes-Scientific

Background & Clinical Implications

Asher Salmon M.D, Ph.DHadassah University Hospital Ein Kerem

• The risk for breast cancer 11 %

• The risk for ovarian cancer 1.4 %

• Only 5-10% are due to genetic predisposition

Family 1

Sharett Institute of Oncology

Family 2: Familial Breast Ovarian Cancer


Clinical Characteristics

• Multiple family relatives diagnosed with breast cancer

• Early age of onset• Higher prevalence of bilateral cancer • Presence of associated tumors (ovary,

colon, prostate).


Familial Breast Cancer

Syndrome Characteristics GeneBRCA1 Breast / Ovary 17qBRCA2 Breast, male/female 13BRCA3 ? ?Lynch II Colon, endometrium 2p;3p; ovary, stomach, brainLi-Fraumeni Sarcoma, brain 17p

adrenocorticalCowdan’s dis Multiple hamartomas PTENChk2 breast-colon (x2BC)ATM


BRCA1 gene:

• chromosome 17q21• Predisposing genetic factors is 5-10%• Female mutation carriers have a 60-80%

life time risk for developing breast cancer• 20-40% life time risk for developing

ovarian cancer.


BRCA2 gene

• Chromosome 13q 12-13• The life-time breast cancer risk – 60-85%• The life-time ovarian cancer risk – 10-20%• Male – 6% lifetime breast risk. • Association with – colon, prostate,

pancreas, gallbladder, bile duct stomach cancer and malignant melanoma.


The Road To Malignancy


Normal

Invasion

MetastasisInherited gene

Somatic mutations)5-6(

Sporadic tumors arise after somatic inactivation of both copies of a tumor suppressor gene


Normal Normal Transformation

Somatic Mutation I Somatic Mutation II


Normal Transformation

Tumor development in BRCA1/2 carriers

Germline mutation Somatic mutation-LOH (Knudson)

Function of BRCA1 and 2 proteins

• Tumor suppressor gene• Transcription pathway • Cell cycle control pathway• DNA damage repair pathway


BRCA gene functionGatekeepers of genomic stability:

BRCA1&2 are in complex with Rad51; Rad51 participate in cellular response to DNA damage (ds breaks)

BRCA1 is phosphorilated by by ATM kinase in response to DNA damage

BRCA1 interacts with p53 induction of p21 cell cycle inhibition

BRCA gene functionControl of sex steroid regulated pathways:

BRCA proteins elevates in puberty and in response to estrogen stimuli

BRCA1 suppress the ER signaling in mammary epithelialcells

BRCA1 mice conditional knockout regulation of mammary ducts morphology

185delAG mutation in exon 2 of BRCA1

• WT: 5’---AAT CTT AGA GTG TCC CA---3’

• Mutant: 5’---AAT CTT AG- T GTC CCA---3’

185delAG: Two bp deletion at codon23, creates a stop codon at codon 39


Ashkenazi Founder Mutations in BRCA1

185delAG Prevalence - 1%

5382insC Prevalence - 0.4%

Ashkenazi Jews (10% and more)20% of Jewish women who developed breast cancer before the age of 40y carry – 185delAG mutation.


• Ashkenazi Jews – 6174delT• Prevalence of 1.2%

• Yemanite Jews - 8752delAG• Prevalence of 1.0%

• Iceland - 999del5

Founder Mutation of BRCA2


Frequency of recurrent BRCA1 and BRCA2 mutations in Healthy Ashkenazi Jewish population

Gene Mutation Exon Frequency

BRCA1 185delAG 2 1.05%5382insC 20 0.11%

BRCA2 6174delT 11 1.36%BRCA1+2 2.5%

Compared to 1:800 in other populations!!!


Frequency of BRCA carriers in the Ashkenazi population in Israel

• Carrier frequency 1 in 40

• Number of Ashkenazi females in Israel 1,000,000

Female Carriers n=25,000


BRCA1 BRCA2BC 56-85 37-85

OC 15-45 10-27 male BC 0? 6

Prostate 6 6-14

Colon 0? 5(not confirmed by population based studies)

•

Lifetime (by age 80 years) Cancer Risks (%) in BRCA1/2 Carriers


BRCA1 breast/ovarian cancer risks


Eles & Poules 2000

BRCA2 breast/ovarian cancer risks


Eles & Poules 2000

Tumor characteristics and prognosis

Ovarian cancer

Serous papillary

not borderline or muscinus

High grade, high p53

Better prognosis: better response to chemo? DDP?

Tumor characteristics and prognosis

Breast cancer

High grade

BRCA1: Higher T

ER-, PR- Her 2- (triple negative)

G3, high pleomorphism, high mitotic count

less DCIS, medullary, distinct gene expression

= Basal like carcinoma

prognosis: worse(?), partially corrected by chemo

Hormonal Risk Factors

• Prolonged exposure to estrogen (increase numbers of menstrual cycle)

• Long-term use of HRT• Long-term use of OC • Age at first live birth • Obesity (in postmenopausal androsteron to

estrone by adipose tissue).


Non-hormonal Risk Factors

• Exposure to ionizing radiation• Alcohol consumption (alcohol exposure to

estrogen).• Smoking• Dietary factors (?) (high diet in fat “well

done” meat).


Oral Contraceptives and Ovarian ca• Modan et al, N Eng J Med, 2001

751 controls, without ovarian cancer, 1.5% BRCA1/2 +840 women with ovarian cancer, 29% BRCA1/2+Oral contraceptive use reduced the risk only in noncarriers.

McLauglin et al, Lancet Oncol 2007800 cases Vs 2400 controls. Reduction in OC risk

50-60% in BRCA1 & 2

Oral Contraceptives and breast ca

• Narod et al, JNCI, 2002.• Matched case-control, 1311 pairs• In BRCA1: OR 1.2.

More than 5y use - OR 1.33 use before age 30 - OR 1.29 diagnosis before age 40 – OR 1.38 use before 1975 – OR 1.42

• No association in BRCA2 (small numbers?)

Risk modifiers *Pregnancies in non-carriers reduction in risk by 5%

with reduction of first birth year by 5y. In carriers-risk opposite.

*Smoking - 1000 case-control carriers, no association with smoking, age start ect.

*physical activity

*low weight at puberty

*Modifiers genes

Prevention

• Surveillance• Prophylactic mastectomy• Prophylactic oophorectomy• Chemoprevention


Early Detection - mammography

Brekelmans et al: 1,200, of them 118 carriers diagnosed by screening: carriers 5/9 (56%)

non-carr 26/35 (74%)Schuer et al: 165 carriers

diagnosed by screening: 6/12 (50%)

More aggressive-Interval cancersBreast density, young age, less spiculated

tumor .

Early detection - mammography

• Kauff et al, 1648 ASCO 2001

215 women in MSKCC

102/215 – BRCA1/2 mutation carriers.

Carriers were less likely to be diagnosed by screening – 20% vs. 39%.

Mutation carriers were more likely to present with palpable mass 67% vs. 47%.

Early detection-mammographyMammograpgy – possible increased sensitivity to XRT due to BRCA mutation

detectibility: lower than in non-carriers

Early detection - MRI

Warner et al: 196 (96 carriers) screened by mammo, US, MRI, BCE

6 tumors detected, all less than 1cm

6 by MRI, 2/6 by mammo, 3/6 by US, 2/6 by BCE

Kohl et al: 192 high risk (35 carriers)

9 tumors detected, all less than 1cm (6-brca1, 1-brca2)

MRI mammo us mammo+us

Sensitivity: 100% 30% 30% 44%

Specificity: 95% 93% 80%

Early detection

Frequency? Interval cancer?

Sensitivity of MRI to high, specificity ?? - many biopsies (cost-13,930 euro per BC by MRI vs 4,930)

No data regarding impact on mortality

In studies some of pt diagnostics, different risk populations

• 639 women Moderate-high risk (according to family history)

• In 214 high risk : expected - 53 • incidence - 3 • Reduction in risk : >90% (p<0.001)• (of them 26 carriers, no BC case)• Reduction in death : 100%


Prophylactic Mastectomy

Hartman L.C.1999 639. HR 214-425

Satisfaction with prophylactic mastectomy (N=562)

Frost M (JAMA) 2000

Choice to have prophylactic mastectomy again (N=567)

Frost M (JAMA) 2000

Prophylactic Mx in carriers

Meijers-Heijboer (NEJM) 139 carriers, 2.9y follow up, oophorectomy

79 :mx - 0 BC63 follow-up - 8 BC (6.7 expected)

HR – 0, p=0.003Rebbeck et alCase-control (adj-mut,age) multicenter, 6y follow up

2/105 mastectomized Vs 184/384 followedHR-0.05, when corrected to oophorectomy 0.09

Prophylactic Mx in carriers

No randomization, no data of impact on survival

More family history-more operated

Those with occult ca. out of analysis

Oophorectomy done in many – also protective


• Bilateral Mastectomy – lowers the incidence of breast cancer by 90%-100%

• Prophylactic Mastectomy an option – 57% of women at high risk.

• Subcutaneous and nipple sparing; risk?, better body image

• Actually performed the surgery – 25%


Frost M (JAMA) 2000

• The role of the health care professional is to provide data about all optopns in a balanced mannaer

• The primary motivation for the procedure must derive from the patient herself



Prophylactic Oophorectomy

Kauff et al (NEJM): no. 170, 140 prior BC, age>35, 20 months follow upProspective non-randomized

98 operated - 3 BC72 controls - 8 BC HR-0.32

*self selection bias*reduction of BC in BRCA1 carriers although usually ER-

Prophylactic Oophorectomy

• Rebbeck T., NEJM, 2002, retrospective• OC risk: Cases: 259 carriers, oophorectomy.

control: 292 – follow up Hazard ratio of OC – 0.04 (2.3%-st I, 0.8%

peritoneal) BC risk: Cases – 99 oohporectomy. 21 BC Control: 142 - no surgery 60 BC Hazard ratio of BC reduced to 0.47

Use of HRT did not negate the reduction in BC risk. (50% of cases vs 19% in controls)

Prophylactic oophorectomy

•Domchek et al, Lancet Oncol, 2006•Retrospective

•188 cases Vs 478 controled•Med follow-up 2-3 years

•Reduction in mortality 70-80%

Option of Chemoprevention

• Oophorectomy / LhRh agonist

» Aromatase inhibitors ?

• Tamoxifen.


Tamoxifen – Prevention TrailsThe NSABP-P1

Risk reduction by 49% Reduction of ER+, but not ER- (Study population: old woman, lobular carcinoma in

situ, atypical ductal hyperplasia)

Of BC patients, 19 carriers. 8-BRCA1 of them 5 treated---RR-1.67 (NS)11-BRCA2 of them 3 treated---RR-0.38 (NS)


Tamoxifen in BRCA1/2 carriers • Narod et al, Lancet 2000. Retrospective

comparisson of tamoxifen use in 209-BB and 384-unilateral BC.

• Tamoxifen reduced the risk of contralateral breast cancer by 50% in carrier of BRCA1/2 Mutations

• BRCA1 – OR- 0.38 (sig, n=476) • BRCA2 – OR- 0.63 (sig, n=117)• In users of >2-4years• When combined with oophorectomy: OR-0.16

Survival bias!!!

Chemoprevention in BRCA1&2 Carriers

• The penetrance curves for breast cancer starts to increase at 35 years.

• The steepest part – 40-50 years.• Chemoprevention 10 years before the

increase in incidence – 35 year at least.


Adverse Effects of Tamoxifen Chemoprevention

Endometrial cancer

Thromboembolic complication

Quality of life – hot flushes, vaginal discharge


Future?

Raloxifen Vs. Tamoxifen

LhRh analogs


Predictive Models• Grann et al JCO, 2002• Simulated cohort of 30-y.o. women. BC & OC

expected incidence from literature. Mortality from SEER.

quality adjusted• Survival : Tamoxifen – 1.8y 2.8y oophorectomy – 2.6y 4.4y tam+oophorec. – 4.6y 6.3y mastectomy - 3.5y 2.6y max &ooph - 4.9y 2.6y

Recommendations to Carriers• Careful follow up of the breast & ovaries

every 6 months• Oophorectomy at 40y or earlier.• Chemoprevention- No!• Risk reduction mastectomy• Colonoscopy age 40?• HRT• Oral contraceptives???


BRCA Mutation Analysis:Benefits

• In healthy carriers: recommendations and guidance of possible prevention and follow up

• In healthy individuals, non-carriers (relatives of carriers) reduces anxiety markedly

• Recommendation to high risk families with no mutation detected; rare variants ???

Should be performed only in the frame of onco-genetic clinic and with psychological and medical support

Should be performed only in the frame of onco-genetic clinic with psychological and medical support

Familial Colorectal Cancer

incidance* CRC risk FAP 1% 100%

HNPCC 1-5% 70-90%

CRC family history 10-15% 15%

Hamartomatous polyposis rare- Peutz Jeghers

- Juvenile polyposis

*among CRC patients

Familial CRC: genes Gene

Non polyposis Syndromes

HNPCC (Lynch, Muir, Turcot) msh2, mlh1, msh6, pms1, pms2 Familial clustering of late onset I1307KAPC, TGFbetaRII

CRC

Polyposis Syndromes FAP APC

Peutz-Jeghers STK11 Juvenile Polyposis SMAD4, PTEN

Characteristics of Hereditary CRC

Early age at onset

Multiple CRC in an individual

Other tumors in family: endometrial, breast, sabecous cyst.

Hamartomatous polyps

HNPCC Incidance: 1/1000

CRC risk: 70-85%

Endometrium: 50%

Synchronous & metachronous CRC: 35%

Other tumours 15%)renal pelvis, ureter, stomach, small bowel, OC, BC, brain(

HNPCC-clinical features

Proximal colon

Better prognosis

Benign adenomas at early age - villous

- more dysplastic

Pathology: TIL (tumor infiltrating lymphocytes Crohn’s like lymphocytic reaction (

HNPCC – Amsterdam criteria

At least 3 cases of HNPCC related tumors

One is first degree relative of the others

2 successive genrations

At least one diagnosed under 50y

FAP excluded

HNPCC – gene function

Correction of mismatch during DNA replication

MSHs complex recognise mismatch

MLH, PMS complex recruited later to accomplish mismatch repair

Also recognises lesions caused by exogenous mutagenes


Mismtch repair deficiency microsatellite instability

Microsatellite – repetative noncoding DNA sequences - susceptible to mismatch replication errores

Mismatch in MS (MSI) frameshift mutations in genes involved in tumor intiation

and progression: APC, kras , p53, TGFbetaRII


TGF beta receptor II – tumor supressor gene

- mutated in 90% of MSI colon cancer

TGF beta family: growth regulation of epithel especialy colon. induces apoptosis

bindes to receptor with 2 subunits RI, RII

RII – includes 10bp polyadenin repeat vulnerable to mutation in MSI tumors

In MSI - low tumors also mutations (other) in TGFbetaRII or downstream genes (SMAD2, SMAD4)

HNPCC – mulecular genetic tests

MSI – 70% of HNPCC tumors 15% of sporadics

50-60% in pt diagnosed under 30y

Half of MSI germline mutation is found

Immunohistochemistry: MLH1, MSH2, MSH6 loss of expression

Mutation detection done after combining MSI +IHC + clinics

In 60% mutation in MLH1, MSH2

HNPCC - treatment interval

20 - 25y colonoscopy 2y

30 – 35y gynecologic examination, vaginal US 1-2y

30 – 35y gastrodoudenoscopy 1-2y

30 – 35y Abdominal US, cytology urine 5y

Total colectomy + ileorectal anastomosis in CRC pt)risk for syn or metachronous – 25 – 40%(

FAP Autosomal dominant

1/8000

Clinical features: hundreds to thousends of polyps ( decades 2 – 3)

100% cancer by age 45

UGI polyps–doudenal: 50-90%, potentially malig) in less then 5%(

gastric : 10%, non malignant

FAP – extracolonic manifestation

Desmoid tumors OsteomasCongenital retinal pigmented epithelium (CRPE, in 75%)

Other tumors: thyroid, hepatoblastoma, brain

Genotype/phenotype correlation

FAP – gene function

Cell adhesion

Differentiation

Apoptosis

Cell cycle regulation

Transmition of signals to the nucleus

FAP - recommendationSurvaillance

intervalGenetic testing 12ySigmoidoscopy 12y 2yColonoscopy, endoscopy 18-20y 1yDuodenoscopy 30y 2y

Prophylactic surgery :proctocolectomy & ileal poutch anastomosis (age; polyps no.

&desmoid tu(.Colectomy & ileorectal anastomosis (rectal ca. mortality-12%)

Breast Cancer Susceptibility :Genes

BRCA1BRCA2

A Frameshift Mutation

A1 A2 A3 A4 A5 A6 A7

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

del

A1 A2 A3 A A stop codon

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

Protein truncation

A Frameshift Mutation


Ashkenazi Mutations in Breast and Ovarian CA Patients

Distribution by age

0

10

20

30

40

50

60

70

80

90

<30 30-39 40-49 50-65 >65

OvaryBreast


Cases with bilateral Controls P

disease (n=209) (n=384)

Radiotherapy 101(48%) 212(55%) 0.110

Chemotherapy 88(42%) 234(61%) 0.0001


III2

Narod, 2000

Frequency of Psychological and Social outcomes of prophylactic mastectomy

Frost M (JAMA) 2000


• Reasons for having had prophylactic mastectomy

• Long-term psychological and social function

• What factors are associated with prophylactic mastectomy satisfaction or dissatisfaction for women at high risk?


Frost M (JAMA) 2000

The contribution of the BRCA mutation to breast and ovarian cancer morbidity in

Ashkenazi patients

0

10

20

30

40

50

60

70

80

90

BC&OC OC BBC BC<40y BC healthy


genetic cancer syndromes-scientific background & clinical implications asher salmon m.d, ph.d...

Documents

genetic predisposition

brca1 gene

lifetime breast cancer

lifetime ovarian cancer

lifetime breast risk

function of brca1

life time risk

dna damage brca1