Retrospective study to estimate the prevalence and describe the clinicopathological characteristics, treatments received, and outcomes of HER2-low breast cancer

BACKGROUND

Approximately 80% of all breast cancers (BCs) are currently categorized as human epidermal growth factor receptor 2 (HER2)-negative [immunohistochemistry (IHC) 0, 1+, or 2+/in situ hybridization (ISH) negative]; approximately 60% of BCs traditionally categorized as HER2-negative express low levels of HER2. HER2-low (IHC 1+ or IHC 2+/ISH-) status became clinically actionable with approval of trastuzumab deruxtecan to treat unresectable/metastatic HER2-low BC. Greater understanding of patients with HER2-low disease is urgently needed.

PATIENTS AND METHODS

This global, multicenter, retrospective study (NCT04807595) included tissue samples from patients with confirmed HER2-negative unresectable/metastatic BC [any hormone receptor (HR) status] diagnosed from 2014 to 2017. Pathologists rescored HER2 IHC-stained slides as HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2 IHC 0 after training on low-end expression scoring using Ventana 4B5 and other assays at local laboratories (13 sites; 10 countries) blinded to historical scores. HER2-low prevalence and concordance between historical scores and rescores were assessed. Demographics, clinicopathological characteristics, treatments, and outcomes were examined.

RESULTS

In rescored samples from 789 patients with HER2-negative unresectable/metastatic BC, the overall HER2-low prevalence was 67.2% (HR positive, 71.1%; HR negative, 52.8%). Concordance was moderate between historical and rescored HER2 statuses (81.3%; κ = 0.583); positive agreement was numerically higher for HER2-low (87.5%) than HER2 IHC 0 (69.9%). More than 30% of historical IHC 0 cases were rescored as HER2-low overall (all assays) and using Ventana 4B5. There were no notable differences between HER2-low and HER2 IHC 0 in patient characteristics, treatments received, or clinical outcomes.

CONCLUSIONS

Approximately two-thirds of patients with historically HER2-negative unresectable/metastatic BC may benefit from HER2-low-directed treatments. Our data suggest that HER2 reassessment in patients with historical IHC 0 scores may be considered to help optimize selection of patients for treatment. Further, accurate identification of patients with HER2-low BC may be achieved with standardized pathologist training.

Zinc-α2-glycoprotein is associated with non-albuminuric chronic kidney disease progression in type 2 diabetes: a retrospective study with 4-year follow-up

AIM

To investigate the association between baseline plasma zinc-α2-glycoprotein and non-albuminuric chronic kidney disease progression in type 2 diabetes.

METHODS

Adults with normoalbuminuria at entry (n=341; age 57±10 years, 52% men) were analysed. Chronic kidney disease progression was defined as a decrease in chronic kidney disease stage and a decline of ≥25% in estimated GFR from baseline. Baseline plasma zinc-α2-glycoprotein levels were quantified by immunoassay, and analysed either as a continuous variable or by tertiles in Cox proportional hazards models. Model discrimination was assessed using Harrell's C-index. A sensitivity analysis was performed on a subset of individuals who maintained normoalbuminuria during follow-up.

RESULTS

Chronic kidney disease progression occurred in 54 participants (16%). Zinc-α2-glycoprotein levels were elevated in chronic kidney disease progressors (P = 0.011), and more progressors were assigned to the higher zinc-α2-glycoprotein tertile than non-progressors. In the unadjusted Cox model, zinc-α2-glycoprotein, both as a continuous variable (hazard ratio 1.72, 95% CI 1.08-2.75) and tertile 3 (vs tertile 1; hazard ratio 2.14, 95% CI 1.10-4.17), predicted chronic kidney disease progression. The association persisted after multivariable adjustment. The C-index of the Cox model increased significantly after incorporation of zinc-α2-glycoprotein into a base model comprising renin-angiotensin system antagonist usage. Sensitivity analysis showed that zinc-α2-glycoprotein independently predicted chronic kidney disease progression among individuals who maintained normoalbuminuria during follow-up.

CONCLUSIONS

Plasma zinc-α2-glycoprotein is associated with chronic kidney disease progression, and may serve as a useful early biomarker for predicting non-albuminuric chronic kidney disease progression in type 2 diabetes.