Which status would most directly support eligibility for HER2-targeted therapy?

• A. HER2 overexpression
• B. ER positivity
• C. Triple-negative status
• D. PR positivity

Answer: (A)

The key idea is that HER2-targeted therapies are effective only when the tumor really has HER2 activity driving its growth. This means the tumor shows HER2 overexpression or HER2 gene amplification. When testing confirms HER2-positive status (often by IHC for protein levels and/or FISH for gene amplification), patients are eligible for these targeted drugs such as trastuzumab or pertuzumab.

Other statuses don't directly indicate eligibility for HER2 therapy. ER positivity or PR positivity point to hormone-driven cancer that’s typically treated with endocrine therapy, not HER2-directed drugs. Triple-negative status means the tumor lacks ER, PR, and HER2, so it generally does not indicate eligibility for HER2-targeted therapy. In practice, only tumors with confirmed HER2 overexpression/amplification are considered for HER2-targeted treatment.