Molecular Classification of Breast Cancer

Dr. S. RajendiranProf. of Pathology

Sri Ramachandra University, Chennai, India

Game Plan Pre-Test

Post-Test

Molecular Molecular Classification Classification of Ca Breastof Ca Breast

WhyWhyHowHow

UtilityUtility

PrognosticatioPrognosticationn

Pit Pit fallsfalls

ReferencesReferences

TakeTakeHome Home

MessageMessage

Pre Test 1•What is the problem in the current

classification of breast cancer?

a. Subjectiveb. Not accuratec. Over treatment of low risk diseases & under treatment of high risk diseasesd. All of the above

Pre Test 2•Which tumor is associated with

good prognosis?

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

Pre Test 3•Herceptin is very useful in the

following type of breast cancer

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

Pre Test 4•Which molecular type of breast cancer

is associated with BRCA 1 mutation?

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

Pre Test 5

•How will you differentiate luminal A and B subtypes?

a. ER positivityb. PR positivityc. Her2 amplification in some tumorsd. ER, PR and Her 2 negative

WHO 2003 classification of Tumors of the Breast

1. Epithelial tumours      1.1 IDC      1.2 ILC      1.3 Tubular      1.4 Invasive cribriform      1.5 Medullary      1.6 Mucinous ca and other tumours           with abundant mucin            1.6.1 Mucinous ca            1.6.2 Cystadenocarcinoma and                    col cell mucinous ca            1.6.3 Signet ring cell ca      1.7 Neuroendocrine tuomurs            1.7.1 Solid neuroendocrine ca            1.7.2 Atypical carcionid tumour            1.7.3 Small cell / oat cell ca            1.7.4 Large cell neuroendocrine                    ca      1.8 Invasive papillary ca      1.9 Invasive micropapillary ca      1.10 Apocrine ca      1.11 Metaplastic carcinomas            1.11.1 Pure epithelial                      metaplastic ca                  1.11.1.1 Squamous cell ca                  1.11.1.2 Adenoca with spin-                               dle cell metaplasia                  1.11.1.3 Adenosquamous ca                  1.11.1.4 Mucoepidermoid ca            1.11.2 Mixed epithlial/ mesen-                      chymal metaplastic ca      1.12 Lipid-rich ca      1.13 Secretory ca      1.14 Oncocytic ca      1.15 Adenoid cystic ca      1.16 Acinic cell ca      1.17 Glycogen-rich clear cell ca      1.18 Sebaceous ca      1.19 Inflammatory ca1.20 Lobular neoplasia            1.20.1 Lobular ca in situ      1.21 Intraductal proliferative lesions            1.21.1 Usual ductal hyperplasia           

      1.21.2 Flat epithelial atypia            1.21.3 Atypical ductal hyper-                      plasia            1.21.4 Ductal carcinoma in situ1.22 Microinvasive ca      1.23 Intraductal papillary neoplasms            1.23.1 Central papilloma            1.23.2 Peripheral papilloma            1.23.3 Atypical papilloma            1.23.4 Intraductal papillary car-                      cinoma            1.23.5 Intracystic papillary ca      1.24 Benign epithelial proliferations            1.24.1 Adenosis including vari-                      ants                  1.24.1.1 Sclerosing                               adenosis                  1.24.1.2 Apocrine adenosis                  1.24.1.3 Blunt duct adenosis                  1.24.1.4 Microglandular                                adenosis                  1.24.1.5 Adenomyoepithelial                               adenosis            1.24.2 Radial scar / complex                      sclerosing lesion      1.25 Adenomas            1.25.1 Tubular adenoma            1.25.2 Lactating adenoma            1.25.3 Apocrine adenoma            1.25.4 Pleomorphic adenoma            1.25.5 Ductal adenoma2. Myoepithelial lesions      2.1 Myoepitheliosis      2.2 Adenomyoeithelial adenosis      2.3 Adenomyoepithelioma      2.4 Malignant myoepithelioma3. Mesenchymal lesions      3.1 Haemangioma      3.2 Angiomatosis      3.3 Haemangiopericytoma      3.4 Pseudoangiomatous stromal            hyperplasia      3.5 Myofibroblastoma

       3.6 Fibromatosis (aggressive)      3.7 Inflammatory myofibroblastic            tumour      3.8 Lipoma            3.8.1 Angiolipoma      3.9 Granular cell tumour      3.10 Neurofibroma      3.11 Schwannoma      3.12 Angiosarcoma      3.13 Liposarcoma      3.14 Rhabdomyosarcoma      3.15 Osteosarcoma      3.16 Leiomyoma      3.17 Leiomyosarcoma 4. Fibroepithelial tumours      4.1 Fibroadenoma      4.2 Phyllodes tumour            4.2.1 Benign            4.2.2 Broderline            4.2.3 Malignant      4.3 Periductal stromal sarcoma, low           grade      4.4 Mammary hamartoma5. Tumours of the nipple      5.1 Nipple adenoma      5.2 Syringomatous adenoma      5.3 Paget disease of the nipple 6. Malignant lymphoma      6.1 Diffuse large B-cell lymphoma      6.2 Burkitt lymphoma      6.3 Extranodal marginal-zone B-cell            lymphoma of MALT type      6.4 Follicular lymphoma 7. Metastatic tumours 8. Tumours of the male breast      8.1 Gynecomastia      8.2 Carcinoma            8.2.1 Invasive            8.2.2 In situ

Why Classification?

•To memorize during the training ?

•To reproduce in the exam ?

•To confuse students, physicians and patients?

Why Classification ?

•To help the learner (improve the understanding)

•To help the physician (inform the prognosis, selection of treatment)

•To help the patient (disease free survival, quality of life)

Current Situation

•Morphological classification

•Histological grade (Nottingham score)

•IHC (ER, PR, her2-neu)

•TNM Stage (clinical & pathological)

Current Problem

•Highly subjective

•Not accurate

•Three tier system (low, intermediate and high grade/risk)

•Over treatment of low risk diseases & under treatment of high risk diseases

Histological grade and Histological grade and survivalsurvival

Pre-Pre-systemic systemic therapytherapy

Post-Post-systemic systemic therapytherapy

Current ProblemSimilar features ........ different outcome

Looking for Looking for

Similar features .......... similar outcome

Molecular Classification

How ?

Perou et al 2000

•40 cases

•8102 microarray

•1753 genes

•496 intrinsic genes

•Subtyping by hierarchial clustering

CK 5,6,14,15,17

High ERNo Her2Low p53,

Ki67

CK 7,8,18,19

ER -ER -PR -PR -

Her2 -Her2 -EGFR, p53, Ki67EGFR, p53, Ki67

ckitckit

Her 2 +++ ER -PR -AR+

High p53, Ki67

Gene profile similar to

normal breast control

Luminal ALuminal A

Luminal BLuminal B

BasalBasal

NormalNormal

Her 2Her 2

Low ERHigher Her2

High p53, Ki67

Molecular Classification

•5 types

•Normal breast like cancers

•Luminal A breast cancers

•Luminal B breast cancers

•Her 2 positive cancers

•Basal like carcinomas

Normal breast like cancers

•Gene expression similar to normal control

•Consistently clustered together with fibroadenoma and normal breast tissue

Result of analyzing admixed “normal” or benign breast tissue

Disappeared

Disappeared

Luminal A breast cancer

•Luminal cytokeratin

•High ER, PR

•Her 2 negative, low proliferation index

•Low histological grade

•Excellent prognosis

•Hormone therapy (Tamoxifen, SERMs & aromatase inhibitors)

•No benefit from chemotherapy

Luminal B breast cancer

•Luminal cytokeratin

•Low ER, PR

•Her 2 +, High proliferation index

•High histological grade

•Poor prognosis

•Hormone therapy (Tamoxifen, SERMs & aromatase inhibitors)

•Some response to chemotherapy

Her2 positive cancer

•No ER, PR

•Her 2 +++, High proliferation index

•High histological grade, node positive

•Poor prognosis

•Response to Herceptin

•Anthracyclin based chemotherapy

Basal Phenotype

•ER, PR & her2neu: Negative

•CK 5/6: Positive

•EGFR: Positive

•p63, p53 and c-kit: Positive

Histology of basal type carcinoma

•Nottingham grade 3

•Syncytial growth with pushing borders

•Geographic necrosis

•Stromal lymphocytes

•Mostly triple negative (ER, PR & her2neu)

•CK 5/6 positive High ki67 index

Similar to Atypical medullary carcinoma

Sensitivity to chemotherapy

•Luminal A/B: 2/30

•Normal breast like: 0/10

•her2neu: 9/20

•Basal like: 10/22 (P value: <0.001)

Heterogenity in basal like sub type

•Histological: Ductal, medullary, adenoid cystic, metaplastic

•CK expression: Variable

•All are not triple negativeTTNN

Basal likeBasal like

Basal like carcinoma

•BRCA 1 mutation (Brain & Lung mets)

•Defect in DNA repair pathway

•Target for new therapies

•PRAP inhibitors

•Platinum based chemo

Basal Type CarcinomaSummary•5-10% of cases

•Poor prognosis

•Good sensitivity to chemotherapy

•BRCA 1 dysregulation

•Most - triple negative by IHC

•Search for better therapies...????

Basal like and TN...?

•Currently no difference in therapy

•Treated as TN

•BRCA 1 screening

Strong association but not interchangeable

IHC vs mRNA profile

Pathology

Luminal A

Luminal B

Her 2 Basal

ER + 96% 20% 46% 12%

Her2 + 12% 20% 100% 10%

Grade 3 19% 53% 74% 84%

ER+, ER+, her2-, LGher2-, LG

ER+, ER+, her2+/-, her2+/-,

LGLG

ER-, ER-, her2+, her2+,

HGHG

ER-, ER-, her2-, HGher2-, HG

Summary

•All breast carcinoma are not alike

•Subtypes associated with outcome

•Subtypes have overlap

ER +ER + BasaBasal CK l CK ++

her2 her2 ++

70-75%70-75% 10-15%10-15% 15-20%15-20% 5-10%5-10%

FortuneTellers

•What is the prognosis?

•Who will respond to particular therapy?

•What will be the treatment for a particular tumor in a person? (Individual cancer treatment)

Traditional factors

•Tumor type

•Nottingham grade

•Margin status

•Lymphnode involvement

•Metastasis

Treatment options

•Surgery

•Radiation

•Hormone therapy

•Chemotherapy

• Tumor type

• Nottingham grade

• Margin status

• Lymphnode involvement

• Metastasis

To give To give oror

Not to giveNot to give

Who should get Chemotherapy?

•Calculators

•Risk stratifiers

1. Adjuvant online1. Adjuvant online2. St. Gallen Criteria2. St. Gallen Criteria3. Gene expression 3. Gene expression signaturesignature

Gene Expression Signature

mRNA

Microarray

RTPCR

1. Top down approach

Subclassify by clinical outcome

what is the pattern in good prognosis group?

2. Bottom up approachSubclssify by biological

hypothesisWhat is the pattern in metastatic tumors?

3. Candidate geneWhat is the effect of a particular

gene?What is the outcome of all the tumors with

p53 mutation?

Commercially available genomic

assays•MammaPrint

•Oncotype Dx

•Theros

•MapQuant Dx

Variable MammaPrint Oncotype Dx Theros MapQuant DX

Type of assay 70 gene assay21 gene

recurrence score

2 gene ratio of H/I and

molecular grade index

Genomic grade

Sample Fresh/frozen FFPE FFPE Fresh/frozen

TechniqueDNA

microarraysQ-RT-PCR Q-RT-PCR

DNA microarrays

Level of evidence

1- strongestV - Weakest

111 11 111 111

FDA FDA approvedapproved

United States United States EuropeEurope

USUS EuropEuropee

MINDACTMINDACT TAILORxTAILORx

Pit falls of Gene Expression

Profiling•Fresh/Frozen tissue - Sampling error

•Not reproducible 100%

•Still overlap exists (but definitely less)

•Host response not considered (Comorbid, drug metabolism, immune status)

•Cost

Post Test 1•What is the problem in the current

classification of breast cancer?

a. Subjectiveb. Not accuratec. Overtreatment of low risk diseases & undertreatment of high risk diseasesd. All of the above

dddd

Post Test 2•Which tumor is associated with

good prognosis?

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

aaaa

Post Test 3•Herceptin is very useful in the

following type of breast cancer

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

bbbb

Post Test 4•Which molecular type of breast cancer

is associated with BRCA 1 mutation?

a. Luminal typeb. Her 2 typec. Normal typed. Basal type

dddd

Post Test 5

•How will you differentiate luminal A and B subtypes?

a. ER positivityb. PR positivityc. Her2 amplification in some tumorsd. ER, PR and Her 2 negative

cccc

Take home message

•Biological rather than morphological

•Selection of patients for chemotherapy (ER+, LN -)

•Individualized treatment - Tailor made (not ready made...!!!!)

70-75%70-75% 10-15%10-15% 15-20%15-20% 5-10%5-10%

Reference

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