Molecular subtypes

Question 1

Basis for the subtypes

Answer 1

• ER/PR receptor
• HER-2/Neu status

Question 2

Done to confirm positivity to HER-2 in cases of equivocal, or even strongly positive results

Answer 2

FISH

Question 3

Types

Answer 3

• Luminal A and B
• HER-2 enriched
• Basal

Question 4

Phenotype

• Luminal A and B
• HER-2 enriched
• Basal

Answer 4

• Luminal AB
  
  • E/R ⊕ and HER2/neu ⊝ and low Ki-67
• Luminal B
  
  • E/R ⊕ and either HER2/neu ⊕ or high Ki-67
• HER-2 enriched
  
  • HER-2 ⊕ and ER/PR ⊕/⊝
• Basal
  
  • Triple negative

Question 5

Frequency

• Luminal A and B
• HER-2 enriched
• Basal

Answer 5

• Luminal A and B
  
  • A – 40 - 55%
  • B – 10%
• HER-2 enriched
  
  • 20%
• Basal
  
  • 15%

Question 6

How to differentiate between Luminal A and B

Answer 6

• A has low proliferation index (low Ki-67)
• B has high proliferation index (low Ki-67)

Question 7

Age as a risk factor for each subtype

Answer 7

• Luminal types
  
  • Increasing age
• Triple negative
  
  • < 40

Question 8

Prognosis of luminal A vs B

Answer 8

Luminal B has worse prognosis

Question 9

Aggresiveness of each subtype

Answer 9

• Lumnial A
  
  • Good prognosis
• Luminal B
  
  • Worse than A
• Basal
  
  • Aggressive
• HER2 ⊕
  
  • Highly aggressive
• Note:*
• Patients with high ER and PR levels have better prognosis compared to those with low or zero levels

Question 10

Treatment

• Luminal A and B
• HER-2 enriched
• Basal

Answer 10

• Luminal A and B
  
  • Tamoxifen (since HER2 negative)
• HER-2 enriched
  
  • Trastuzumab (since HER positive)
• Basal
  
  • In study (since triple negative)