Association Between the HER2 Protein Expression Level and the Efficacy of Neoadjuvant Chemotherapy in HER2-Positive Breast Cancer

Effect of Estrogen Receptor on the Relationship Between HER2 Immunohistochemistry Score and Pathological Complete Response to Neoadjuvant Treatment in HER2-Positive Breast Cancer

Purpose: We aimed to investigate whether estrogen receptor (ER) status affects the predictive role of the human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) score on the efficacy of neoadjuvant treatment for HER2-positive breast cancer. Methods: This retrospective study comprised 167 individuals diagnosed with HER2-positive invasive breast cancer who had undergone neoadjuvant treatment and surgery. Uni- and multivariable logistic regression analyses were performed on the relationship between the HER2 IHC score and total pathological complete response (tpCR), breast pathological complete response (bpCR), or axillary partial response (apCR). Subgroup analyses were used to investigate whether the relationship between the HER2 IHC score and tpCR, bpCR, or apCR differed by ER or PR status. Results: The overall tpCR rate for HER2-positive breast cancers treated with neoadjuvant treatment was 41.32% (69 of 167). The tpCR, bpCR, and apCR rates were greater in the HER2 IHC 3+ group (tpCR: IHC 3 + 47.69% vs. IHC 2 + 18.92%, p=0.009). Significant interactions between HER2 IHC score and tpCR or bpCR were found in subgroup analyses based on ER status (tpCR: p for interaction = 0.001; bpCR: p for interaction = 0.001). Among ER-positive patients, the HER2 IHC 2+ group had substantially decreased tpCR, bpCR, and apCR rates than the HER2 IHC 3+ group (tpCR rate: p=0.003; bpCR rate: p=0.002; apCR rate: p=0.002). For ER-negative individuals, the tpCR, bpCR, and apCR rates did not differ significantly among the HER2 IHC 3+ versus HER2 IHC 2+ groups. Similarly, interactions between HER2 IHC score and tpCR, bpCR, or apCR were found in subgroup analyses based on PR status. Conclusion: HER2 IHC 2+ may indicate a decreased tpCR rate, bpCR rate, and apCR rate to neoadjuvant treatment in HR-positive patients having HER2-positive breast cancer, but not in HR-negative patients.

Exploring the effectiveness of molecular subtypes, biomarkers, and genetic variations as first-line treatment predictors in Asian breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Breast cancer incidence has been on the rise significantly in the Asian population, occurring at an earlier age and a later stage. The potential predictive value of molecular subtypes, biomarkers, and genetic variations has not been deeply explored in the Asian population. This study evaluated the effect of molecular subtype classification and the presence or absence of biomarkers and genetic variations on pathological complete response (pCR) after neoadjuvant treatment in Asian breast cancer patients.

METHODS

A systematic search was conducted in MEDLINE (PubMed), Science Direct, Scopus, and Cochrane Library databases. Studies were selected if they included Asian breast cancer patients treated with neoadjuvant chemotherapy and contained data for qualitative or quantitative analyses. The quality of the included studies was assessed using the Newcastle Ottawa Scale. Following the random effects model, pooled odds ratios or hazard ratios with 95% confidence intervals for pCR were analysed using Review Manager Software. Heterogeneity between studies was assessed using Cochran's Q-test and I2 test statistics.

RESULTS

In total, 19,708 Asian breast cancer patients were pooled from 101 studies. In the neoadjuvant setting, taxane-anthracycline (TA) chemotherapy showed better pCR outcomes in triple-negative breast cancer (TNBC) (p<0.0001) and human epidermal growth factor receptor 2 enriched (HER2E) (p<0.0001) than luminal breast cancer patients. Similarly, taxane-platinum (TP) chemotherapy also showed better pCR outcomes in TNBC (p<0.0001) and HER2E (p<0.0001). Oestrogen receptor (ER)-negative, progesterone receptor (PR)-negative, HER2-positive and high Ki-67 were significantly associated with better pCR outcomes when treated with either TA or TP. Asian breast cancer patients harbouring wildtype PIK3CA were significantly associated with better pCR outcomes when treated with TA in the neoadjuvant setting (p=0.001).

CONCLUSIONS

In the neoadjuvant setting, molecular subtypes (HER2E and TNBC), biomarkers (ER, PR, HER2, HR, Ki-67, nm23-H1, CK5/6, and Tau), and gene (PIK3CA) are associated with increased pCR rates in Asian breast cancer patients. Hence, they could be further explored for their possible role in first-line treatment response, which can be utilised to treat breast cancer more efficiently in the Asian population. However, it needs to be further validated with additional powered studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021246295.

Differential response of HER2-positive breast cancer to anti-HER2 therapy based on HER2 protein expression level

BACKGROUND

Increasing data indicate that HER2-positive (HER2 + ) breast cancer (BC) subtypes exhibit differential responses to targeted anti-HER2 therapy. This study aims to investigate these differences and the potential underlying molecular mechanisms.

METHODS

A large cohort of BC patients (n = 7390) was utilised. The clinicopathological characteristics and differential gene expression (DGE) of HER2+ immunohistochemical (IHC) subtypes, specifically HER2 IHC 3+ and IHC 2 + /Amplified, were assessed and correlated with pathological complete response (pCR) and survival in the neoadjuvant and adjuvant settings, respectively. The role of oestrogen receptor (ER) status was also investigated.

RESULTS

Compared to HER2 IHC 3+ tumours, BC patients with IHC 2 + /Amplified showed a significantly lower pCR rate (22% versus 57%, P < 0.001), shorter survival regardless of HER2 gene copy number, were less classified as HER2 enriched, and enriched for trastuzumab resistance and ER signalling pathway genes. ER positivity significantly decreased response to anti-HER2 therapy in IHC 2 + /Amplified, but not in IHC 3 + BC patients.

CONCLUSION

In HER2 + BC, overexpression of HER2 protein is the driver of the oncogenic pathway, and it is the main predictor of response to anti-HER2 therapy. ER signalling pathways are more dominant in BC with equivocal HER2 expression. personalised anti-HER2 therapy based on IHC classes should be considered.

Effect of the HER-2/CEP17 ratio in IHC 2+/FISH-amplified breast cancer on pathological complete response to neoadjuvant pertuzumab and trastuzumab treatment-a retrospective cohort study

Background

Human epidermal growth factor receptor-2 (HER-2) protein expression level could serve as a predictor of pathological complete response (pCR) to neoadjuvant trastuzumab-containing regimens. The aim of the present study was to evaluate whether pCR to neoadjuvant trastuzumab and pertuzumab treatment is dependent on the level of the HER-2/CEP17 (chromosome enumeration probe 17) ratio in immunohistochemistry (IHC) 2+/fluorescence in situ hybridization (FISH)-amplified breast cancer.

Methods

Patients with primary IHC 2+/FISH-amplified breast cancer who underwent neoadjuvant anti-HER-2 dual-targeted therapies were retrospectively included between January 1, 2020 and May 30, 2021. The primary predictive variable was HER-2/CEP17 ratio, and the primary outcome variable was pCR. Other variables consisted of age, menopausal status, tumor-node-metastasis (TNM) stage, estrogen receptor (ER), progesterone receptor (PgR), and Ki-67. Association between clinicopathologic variables and pCR was evaluated using the chi-square test and logistic regression analysis.

Results

The median age of the patients was 51.78 years (25-67 years), and 50.7% of the patients were in the premenopausal stage. The clinical stage at diagnosis was Stage III in 38 patients (55.1%). Of all patients, 40.6% patients were estrogen receptor positive, and 75.4% patients had a Ki-67 index of ≥30%. The overall pCR (ypN0/isypN0) rate was 31.9%. Patients with HER-2/CEP17 ratio ≥6.0 had a pCR rate of 55.0%, it was statistically higher than 22.4% in patients with HER-2/CEP17 ratio <6.0. Logistic regression analysis confirmed the independent association between HER-2/CEP17 ratio and pCR (P=0.020, OR: 5.203, 95% CI: 1.302-20.783).

Conclusions

A HER-2/CEP17 ratio ≥6.0 might be related to more achievement of pCR in the neoadjuvant anti-HER-2 dual-targeted therapies. Further studies are needed to validate the finding.

Clinical and Therapeutic Factors Vary by Prognosis in Patients with Pathological Complete Response After Neoadjuvant Therapy for Breast Cancer

Purpose

To determine clinical predictors of recurrence and metastasis in patients with pathological complete response (pCR) after neoadjuvant chemotherapy (NCT).

Methods

Patients treated with NCT who achieved pCR (n=285) were classified into three groups according to pre-NCT clinical stage (cStage): group I (IIa–IIb), group II (IIIa), and group III (IIIb–IIIc). Survival was analysed using the Kaplan–Meier method. The relationships between clinicopathological factors and recurrence were determined using Cox regression analysis.

Results

The median follow-up was 31 months. The 3-year disease-free survival and overall survival rates in groups I, II, and III were 92.7%, 87.8%, and 66.7% (P < 0.01) and 98.6%, 98.3%, and 90.6% (P=0.370), respectively. Lymph node status and tumour size were independent risk factors for recurrence and metastasis after NCT. In the human epidermal growth factor receptor 2-positive subgroup, advanced cStage and lymph node metastasis were associated with recurrence (P < 0.01). In the hormone receptor-positive subgroup, disease-free survival rates differed for cStages I–II compared to cStage III (P=0.049) and clinical node status 0–2 compared to clinical node status 3 (P=0.037).

Conclusion

Pre-NCT cStage predicted the prognosis of pCR for different breast cancer subtypes. Patients with advanced cStage, lymph node metastasis, and large tumour sizes had a higher risk of recurrence or metastasis.