A Novel Prognostic Scoring System Integrating Gene Expressions and Clinicopathological Characteristics to Predict Very Early Relapse in Node-Negative Estrogen Receptor-Positive/HER2-Negative Breast Cancer

Prognostic values of clinical and molecular features in HER2 low-breast cancer with hormonal receptor overexpression: features of HER2-low breast cancer

Background

Human epidermal growth factor receptor 2 (HER2) low breast cancer was considered as a distinct subtype different from HER2-zero breast cancer. Our study aimed to investigate the prognostic values of clinicopathological features and recurrence score (RS) in HER2-low and HER2-zero hormone receptor (HR)-positive breast cancer patients.

Methods

A total of 2099 HR + primary female breast cancer patients diagnosed between Jan 2009 and Jan 2019 were collected. Tumors with immunohistochemistry 1 + /2 + and negative in situ hybridization results were defined as HER2-low. We compared the clinical and genetical features of HER2-low (n = 1732) and HER2-zero (n = 367) breast cancer and their prognostic values.

Results

Estrogen receptor (ER) high expression (> 90%) was more common in HER2-low breast cancer than HER2-zero breast cancer (78.2% vs 58.6%, p < 0.01). Five-year disease-free survival (DFS) was similar between HER2-zero and HER2-low subgroups (92.3% vs 93.3%, p = 0.83). The predictive value of RS was only significant in HER2-zero patients (p = 0.03). The proliferation-related genes performed well in predicting DFS in HER2-zero patients, but not in HER2-low patients (p for interaction < 0.01). The higher HER2 module score was correlated with worse DFS only in HER2-low patients (p = 0.04).

Conclusion

We observed similar survival outcomes between HER2-low and HER2-zero HR + patients. HER2-low patients had a higher proportion of ER high expressed tumors than HER2-zero patients did. RS and its proliferation module might be less clinically meaningful to HER2-low patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-022-01364-y.

Impact of Different Modules of 21-Gene Assay in Early Breast Cancer Patients

BACKGROUND

The 21-gene assay recurrence score (RS) provides additional information on recurrence risk of breast cancer patients and prediction of chemotherapy benefit. Previous studies that examined the contribution of the individual genes and gene modules of RS were conducted mostly in postmenopausal patients. We aimed to evaluate the gene modules of RS in patients of different ages.

METHODS

A total of 1,078 estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients diagnosed between January 2009 and March 2017 from Shanghai Jiao Tong University Breast Cancer Data Base were included. All patients were divided into three subgroups: Group A, ≤40 years and premenopausal (n = 97); Group B, >40 years and premenopausal (n = 284); Group C, postmenopausal (n = 697). The estrogen, proliferation, invasion, and HER2 module scores from RS were used to characterize the respective molecular features. Spearman correlation and analysis of the variance tests were conducted for RS and its constituent modules.

RESULTS

In patients >40 years, RS had a strong negative correlation with its estrogen module (ρ = -0.76 and -0.79 in Groups B and C) and a weak positive correlation with its invasion module (ρ = 0.29 and 0.25 in Groups B and C). The proliferation module mostly contributed to the variance in young patients (37.3%) while the ER module contributed most in old patients (54.1% and 53.4% in Groups B and C). In the genetic high-risk (RS >25) group, the proliferation module was the leading driver in all patients (ρ = 0.38, 0.53, and 0.52 in Groups A, B, and C) while the estrogen module had a weaker correlation with RS. The impact of ER module on RS was stronger in clinical low-risk patients while the effect of the proliferation module was stronger in clinical high-risk patients. The association between the RS and estrogen module was weaker among younger patients, especially in genetic low-risk patients.

CONCLUSIONS

RS was primarily driven by the estrogen module regardless of age, but the proliferation module had a stronger impact on RS in younger patients. The impact of modules varied in patients with different genetic and clinical risks.