The most commonly diagnosed cancer worldwide–where HER2 dimerization and Akt activation offer functional biomarker opportunities.
HER2 testing by IHC and FISH determines eligibility for trastuzumab and pertuzumab. But HER2 expression alone doesn't capture the full biology. HER2 signals primarily through heterodimerization with HER3, which provides the PI3K-binding sites that drive downstream Akt activation.
Pertuzumab was specifically designed to block the HER2-HER3 interaction domainLoading.... Functional measurement of dimerization state could identify patients most likely to benefit from pertuzumab-containing regimens.
The Current Approach: Breast cancer treatment is guided by HER2, ER, and PR status. But these tests measure expression, not function.
The Opportunity: HER2 signals primarily through HER2/HER3 dimerization. Patients with "low" HER2 expression but active HER2/HER3 signaling might benefit from HER2-targeted therapy but are currently missed.
High-throughput timeLoading...-resolved FRETLoading... measurement of Akt activationLoading... state in breast cancer tissue microarrays demonstrated that activated Akt correlates with poor prognosis, while total Akt expression does not.
This finding, published in Cancer Research (2014), established the principle that conformational/interaction state provides superior prognostic information compared to expression levels–the foundation of the functional biomarkerLoading... paradigm.
The Key Study: In 164 breast cancer patients, measuring Akt activation (not just Akt presence) predicted who would have worse outcomes.
The Finding: Traditional IHC measuring Akt protein levels showed NO prognostic correlation. FRET measuring Akt activation predicted both disease-free and overall survival.
The Message: Same protein, two measurement approaches, completely different clinical utilityLoading....
Foundational Validation: Breast cancer was the first malignancy where FRET-based functional biomarkers demonstrated clinical utilityLoading.... The 2014 study[1] of 164 patients established a new paradigm.
Akt activation measured by amplified FRET significantly predicted both disease-free survival (P=0.036[1], HR=0.634) and overall survival (P=0.013[1], HR=0.570). Traditional IHC intensity ratios showed no prognostic correlation.
Click citation numbers to view full references in QF-Pro Applications & Clinical EvidenceLoading...
Where it started: The 164-patient breast cancer study established the paradigm. Akt activation predicted both disease-free and overall survival. Expression testing? No correlation whatsoever. Same protein, two measurement methods, completely different clinical utilityLoading....
