Transcript Dia 1

Hereditary tumours to be
aware of
Gerd JACOMEN
Dept. of Pathology
What is the link?
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Malignant tumours are caused by
genetic changes
Hereditary diseases are genetically
transmitted
Familial clusters of malignancies
Sporadic/Familial genetic changes
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Mutation can be sporadic in 1
somatic cell: epigenetic
Mutation can be present in a germ
cell:
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Germline mutation
All cells derived from that cell will
harbour the mutation
Can be inherited or new
Familial tumours of the uterine
corpus
95% are sporadic
5% are familial
Lynch syndrome
Variant: Muir-Torre syndrome
Cowden syndrome
BRCA1
HNPCC
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Hereditary nonpolyposis colorectal
cancer syndrome
Lynch
Autosomal dominant
Germline mutations in mismatch
repair genes
Genes that are responsible for correcting
errors (mismatches) during DNA
replication
Caretaker genes
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Normal function: helps genome to
be stable during replication
DNA Mismatch repair genes
Microsatellites: repetitive DNA
sequences
Prone to replication errors
Normally corrected by Mismatch
repair system
Microsatellite instability
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Whenever Mismatch repair genes do
not function
Result: microsatellites are no longer
“stable” during replication
Hence: Microsatellite Instable
MSS, MSI-Low, MSI-High
Involved genes
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MLH1, MSH2, MSH6, PMS2
Are all MSI-High tumours Lynch?
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20-25% of all endometrial Ca are
MSI-H
75% are sporadic: epigenetic
silencing of MLH1 (promotor
methylation)
Remaining cases: mostly Lynch
associated
Ca 2% of all endometrial cancers!
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Age dependent: 9% in younger
patients
Recognising is important
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Patient and family have increased
risk for malignancies
Genetic counseling/testing
Gynecologic malignancy is sentinel
cancer in 50%
Features that raise suspicion
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Familial anamnesis
Clinical
Gross
Histology
Familial anamnesis
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Not only gynecologic malignancies
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Not only females
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Take your time!
Malignancy in Lynch
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Increased risk of multiple
malignancies
Colon
Endometrium
Ovary
Stomach
Urinary tract
Hepatobiliary tract
Small intestine
Brain
Clinical
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Other malignancies?
Age
BMI
How to diagnose Lynch?
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Def: germline mutation in DNA
mismatch repair genes
Mutation analysis is definitive test
Expensive and time consuming
Patient consent needed
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Screening!
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Simple screening:
immunohistochemistry
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Using Ab against MLH1, PMS2,
MSH2, MSH6: detection of MSI-H
tumours
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Sensitivity 91%
Specificity 83%
IHC result
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Expression can direct mutational
analysis
+ staining with all 4 Abs: no further
testing
(except if clinical suspicious)
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Importance of IHC result
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Loss of MSH2 and/or MSH6 is
virtually diagnostic for Lynch!
Loss of MLH1 or PMS2 can still be
epigenetic (= not because of
germline mutation)
Advantage of IHC as screening
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Simple
Inexpensive
Readily available
Can direct gene sequencing
Disadvantages of IHC
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Interpretation can be problematic
10% of germline mutations remain
undetected by IHC
Loss of expression can be
epigenetic
= not Lynch, but sporadic
Breast Cancer and Lynch
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Breast Cancer Research
2012,14:R90
Breast Cancer Research
2012,14:110
MSI in breast Ca
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0-3% in sporadic breast Ca
> 50% of breast Ca in Lynch
syndrome mutation carriers
Features of Lynch associated
breast Ca
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Same
Same
Same
Same
Same
Same
age
type
grade
stage
receptor and HER2 status
chemotherapy?
Which endometrial Ca should be
stained?
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< 50 ys
Non-endometrioid Ca < 60 ys
Lower uterine segment
Multicentric or heterogeneity
Peritumoral lymphocytes
TIL > 42/10 HPF
“hard to type” Ca
Familial/personal history
Hereditary tumours of ovary and
fallopian tube
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10% of all ovarian Ca are
associated with inherited germline
mutations
BRCA1/2
Lynch
Lifetime risk for mutation carriers
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BRCA1: 66%
BRCA2: 10-20%
MLH1/MSH2: 3-12%
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Global Western population <2%
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BRCA1/BRCA2
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Inherited mutations in BRCA1 or
BRCA2 genes
BRCA1/BRCA2 act as tumour
suppressor genes
Autosomal dominant
Tumour suppressor genes
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Normal function: gene encodes for
protein involved in control of normal
cell cycle
Of each gene are 2 copies in a cell:
2 mutations are needed before the
protein will not be encoded properly
2 mutations: 1 in each allele
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First: makes cell “vulnerable”
Mutation on second allele: no longer
synthesis of normal protein
No longer normal function
Frequency of BRCA-mutation
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0.3% of women is carrier of the
mutation
2% of Ashkenazi jews
Histology of BRCA associated ovarian
Ca
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Type: Serous
Grade: High
Stage: Advanced
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BRCA1 = BRCA2
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What is not associated with BRCA?
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Mucinous Ca
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If high grade/high stage: think of
metastasis first!
Low grade serous
Borderline serous
BRCA1/2 associated ovarian/tubal Ca
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Since high risk of Ca if carrier:
prophylactic BSO
At age 35 ys, or after child-bearing
is completed
Prophylactic BSO
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Occult cancers
Tubal intraepithelial Ca
Occult cancers
= Ca in absence of preoperative
evidence of malignancy
4-10% of prophylactic BSO
Can measure up to 5 cm
Where?
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Most are located at tubal fimbriae
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Due to oxidative stress at ovulation
Prognosis
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Even little tumours may metastasise
Complete staging necessary as for
serous Ca ovary
Precursor lesions
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Tubal Intraepithelial Carcinoma
(TIC)
In 8% of prophyactic BSO
+ for p53
High Ki67 (>50%)
Prognosis
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Uncertain
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Some cases may metastasise
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Chemotherapy not considered
necessary
Precursor lesions of TIC
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SCOUT
p53 signature
Proliferative p53 signature
Importance in routine setting
unknown
p53 signature
p53
Ki67
BRCA1/2 and breast cancer
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Lifetime risk of breast Ca if carrier:
BRCA1: 70%
 BRCA2: 45%
Other risk factors remain important
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Histopathologic features of BRCA
associated breast Ca
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Invasive Ca of no special type
(BRCA1)
Grade 3
Triple negative
p53 positive
Basal CKs positive
Hereditary diffuse gastric cancer
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Families with diffuse gastric cancer
and lobular Ca breast
Germline mutations of CDH1 gene
(E-cadherin)
Diagnostic criteria
≥ 2 cases of diffuse gastric cancer in
1st or 2nd degree relatives, at least
1 diagnosed < age 50
or
≥ 3 cases of diffuse gastric cancer in
1st or 2nd degree relatives,
regardless of age at diagnosis
Breast cancer in HDGC
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Females in HDGC families are at
increased risk of breast Ca
Lifetime cumulative risk of 60% by age
80
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Most are lobular Ca
Gastric biopsy of patient with lobular Ca
Atypical cells and signet cells in stroma
Diagnosis?
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Lobular Ca breast and gastric
diffuse Ca are similar
Metastasis?
2 separate primaries?
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Treatment is completely different!
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ER
Take home messages
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Familial tumours can be
encountered every day
High level of suspicion
Detection is important for genetic
counseling
Take home messages 2
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Familial anamnesis
Not limited to the same cancer
Not limited to gyneco/breast
Not limited to female members