Receptor discordance and phenotype change in metastatic breast cancer

Retrospective analysis of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki67 changes and their clinical significance between primary breast cancer and metastatic tumors

Objective

To explore the relationship between receptor heterogeneity and clinicopathological characteristics in 166 patients with invasive breast cancer during metastasis.

Methods

We conducted a retrospective analysis of 166 patients diagnosed with metastatic breast cancer through biopsy, who were admitted to our hospital from January 2018 to December 2022. Statistical analysis was employed to assess the heterogeneity of receptors in both primary and metastatic lesions, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki67, as well as their association with clinicopathological features such as tumor size, lymph node metastasis, treatment regimen, and disease-free survival.

Results

The discordant expression rates of ER, PR, HER2, Ki-67 and Luminal classification between primary and metastatic lesions were 21.7%, 41.6%, 8.9%, 34.4% and 36.8%, respectively. There is a significant difference in disease-free survival between patients with consistent and inconsistent receptor status of primary and metastatic lesions, which is statistically significant. The median DFS for primary HER2(-) to metastatic HER2(+) was 84 months, which was relatively high. The Cox multivariate regression analysis revealed that the expression differences of ER, PR, HER2, and Ki67 were not influenced by endocrine therapy and chemotherapy. However, a statistically significant difference in HER2 expression was observed with targeted therapy. Tumor size was correlated with ER and Ki67 receptor status (P = 0.019, 0.016). Tumor size was not correlated with PR, and HER2 (P = 0.679, 0.440). Lymph node metastasis was not associated with changes in ER, PR, HER2, and Ki67. The discordant rates of ER, PR, HER2, and Ki-67 in patients with local recurrence were 22%, 23.7%, 5.1%, and 28.8% respectively, whereas those in patients with distant metastasis were 21.5%, 36.4%, 10.3%, and 31.8% respectively.

Conclusions

The expression levels of ER, PR, HER2, and Ki-67 in primary and metastatic breast cancer exhibit heterogeneity, which is closely associated with the prognosis and treatment outcomes of patients.

SM, Jacob L, Babu G. Study of Biomarker Discordance between Primary and Recurrent Sites and its Clinical Implications in Metastatic Breast Cancer : A Single Institutional Study from India

S. Shanthala Immunophenotypic discordance of receptors between primary and metastatic sites significantly impacts treatment outcomes. Current international guidelines recommend rebiopsy of accessible metastatic lesions to reassess tissue biomarkers. While existing literature on biomarker changes is conflicting and heterogeneous, similar studies on the Indian cohort of breast cancer patients are lacking. In this context, we aimed to evaluate the frequencies of biomarker changes between biopsies from primary and recurrent sites, and their association with various clinicopathological characteristics, including the type of metastasis and treatment in metastatic breast cancer (MBC) patients. This is an ambispective study performed at a single center. Immunohistochemical (IHC) expression of paired primary and recurrence samples of MBC patients was reviewed for the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 (HER2), and Ki-67. Concordance, loss, and gain of receptors were assessed based on the Allred scores for ER, PR, and HER2. Ki-67 was assessed based on a 14% cutoff. Further, receptor changes were studied in relation to age, menopausal status, morphology, grade, stage, metastatic sites, interval between biopsies, and treatment. At progression, biopsies were obtained from 41.18% of locoregional recurrence and 58.82% of metastatic sites. Despite high discordance of 47% for ER and 68.6% for PR, true receptor conversion was observed in 9.8%, 21.56%, and 5.88% for ER, PR, and HER2, respectively. There was a significant correlation between age and ER discordance ( p  = 0.029). Loss in PR significantly correlated with a gain in Ki-67. Of all the metastatic sites, the lung was significantly associated with PR and Ki-67 concordance ( p  = 0.008 and p  = 0.0425, respectively). Discordance of receptors was neither related to the sites of biopsy (local recurrence or metastatic site) nor to the time interval between biopsies, prior chemotherapy, or hormone therapy. In conclusion, metastatic progression of the disease is accompanied by age-dependent discordance of ER. Unparalleled changes in PR in relation to ER suggest that ER-independent pathways may influence PR expression in MBC. Furthermore, the concurrence of PR loss with Ki-67 gain indicates an aggressive phenotype with disease progression. Hence, follow-up testing of samples for receptor expression is beneficial in determining prognosis and guiding therapeutic decisions.

Dynamic whole-body [18F]FES PET/CT increases lesion visibility in patients with metastatic breast cancer

BACKGROUND

Correct classification of estrogen receptor (ER) status is essential for prognosis and treatment planning in patients with breast cancer (BC). Therefore, it is recommended to sample tumor tissue from an accessible metastasis. However, ER expression can show intra- and intertumoral heterogeneity. 16α-[18F]fluoroestradiol ([18F]FES) Positron Emission Tomography/Computed Tomography (PET/CT) allows noninvasive whole-body (WB) identification of ER distribution and is usually performed as a single static image 60 min after radiotracer injection. Using dynamic whole-body (D-WB) PET imaging, we examine [18F]FES kinetics and explore whether Patlak parametric images ( K i ) are quantitative and improve lesion visibility.

RESULTS

This prospective study included eight patients with metastatic ER-positive BC scanned using a D-WB PET acquisition protocol. The kinetics of [18F]FES were best characterized by the irreversible two-tissue compartment model in tumor lesions and in the majority of organ tissues. K i values from Patlak parametric images correlated with K i values from the full kinetic analysis, r2 = 0.77, and with the semiquantitative mean standardized uptake value (SUVmean), r2 = 0.91. Furthermore, parametric K i images had the highest target-to-background ratio (TBR) in 162/164 metastatic lesions and the highest contrast-to-noise ratio (CNR) in 99/164 lesions compared to conventional SUV images. TBR was 2.45 (95% confidence interval (CI): 2.25-2.68) and CNR 1.17 (95% CI: 1.08-1.26) times higher in K i images compared to SUV images. These quantitative differences were seen as reduced background activity in the K i images.

CONCLUSION

[18F]FES uptake is best described by an irreversible two-tissue compartment model. D-WB [18F]FES PET/CT scans can be used for direct reconstruction of parametric K i images, with superior lesion visibility and K i values comparable to K i values found from full kinetic analyses. This may aid correct ER classification and treatment decisions. Trial registration ClinicalTrials.gov: NCT04150731, https://clinicaltrials.gov/study/NCT04150731.

More Than Meets the Eye: A Case of Breast Cancer Switching from Being Luminal-Androgen-Receptor-Positive to Being Hormone-Receptor-Positive

Triple-negative breast cancer (TNBC) represents about 15% of all breast cancers and is usually characterized by aggressive clinical behavior and a poor prognosis. Four TNBC subgroups have been previously defined with different molecular profiles: (i) luminal androgen receptor (LAR), (ii) mesenchymal (MES), (iii) basal-like immunosuppressed (BLIS) and (iv) basal-like immune-activated (BLIA). Among these, LAR is characterized by the expression of the androgen receptor (AR), and exhibits genomic characteristics that resemble luminal breast cancers, with a still undefined prognosis and clinical behavior. Here, we report a case of a woman affected by recurring LAR TNBC, which underwent phenotypic changes throughout its natural history. After the initial diagnosis of LAR breast cancer, the patient experienced local recurrence with strong expression of the estrogen receptor. Due to this finding, she started treatment with a CDK4/6-inhibitor and an aromatase inhibitor, followed by oral vinorelbine, both with dismal outcomes. Then, she received everolimus and exemestane, which determined temporary disease stabilization. An extensive NGS analysis of tumor tissue showed PIK3CA and HER2 mutations. Our case is consistent with previous reports of LAR breast cancer and underlines the potential utility of re-biopsy and molecular testing in breast cancer (BC), especially in rare subtypes.

Discrepancies in Hormone Receptor and HER2 Expression between Malignant Serous Effusions and Paired Tissues from Primary or Recurrent Breast Cancers

INTRODUCTION

Immunohistochemistry (IHC) for the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) biomarkers has prognostic and therapeutic value in breast cancer. This study aimed to compare the expression of ER, PR, and HER2 between paired malignant effusions and tissue samples of breast cancer.

METHODS

Our electronic archive was searched for all effusions diagnosed as breast carcinomas within a pre-defined period (January 2018-October 2021). Next, their cell blocks (CBs) were subjected to ER, PR, HER2 IHC, or in situ hybridization, in addition to EGFR IHC. The expression of hormone receptors (HRs) and HER2 was subsequently compared between tissue and effusion cytology samples derived from the same patients.

RESULTS

Only 2/76 (2.6%) of the breast cancer patients analyzed showed a malignant effusion at their initial presentation. ER, PR, and HER2 discordance rates between paired malignant effusions and tissue samples obtained at initial diagnosis were 24.3% (17/73), 40.8% (29/71), and 9.1% (6/66), respectively. The HR-/HER2- status was found more often at effusions compared to paired tissue biopsies obtained at initial diagnosis (30/70 vs. 17/70; p < 0.001). In addition, the HR-/HER2- status was significantly associated with an earlier development of a malignant effusion, when found at initial diagnosis (p < 0.001; log-rank test), first recurrence/metastasis (either solid or effusion) (p = 0.012; log-rank test), effusion samples (p = 0.007; log-rank test), and any tumor sample obtained (p = 0.009; log-rank test). Lastly, EGFR overexpression in the HR-/HER2- effusion samples was significantly associated with a shorter post-effusion survival (p = 0.019; log-rank test).

CONCLUSION

Serous effusion cytology provides high-quality material for ancillary techniques, especially when CBs are prepared, reflecting cancer heterogeneity.

The Role of Nodes and Nodal Assessment in Diagnosis, Treatment and Prediction in ER+, Node-Positive Breast Cancer

The majority of breast cancers are oestrogen receptor-positive (ER+). In ER+ cancers, oestrogen acts as a disease driver, so these tumours are likely to be susceptible to endocrine therapy (ET). ET works by blocking the hormone's synthesis or effect. A significant number of patients diagnosed with breast cancer will have the spread of tumour cells into regional lymph nodes either at the time of diagnosis, or as a recurrence some years later. Patients with node-positive disease have a poorer prognosis and can respond less well to ET. The nodal metastases may be genomically similar or, as is becoming more evident, may differ from the primary tumour. However, nodal metastatic disease is often not assessed, and treatment decisions are almost always based on biomarkers evaluated in the primary tumour. This review will summarise the evidence in the field on ER+, node-positive breast cancer, including diagnosis, treatment, prognosis and predictive tools.

Higher rate of progesterone receptor positivity in skeletal metastases of breast cancer with a pathological fracture vs those without fracture

Identifying risk factors for fracture occurrence in breast cancer (BC) skeletal metastases (SM) may guide the management of such bone deposits. There is sparse evidence regarding receptor status in SM and their relationship to fracture occurrence. Our study aimed to determine the relationship between estrogen (ER), progesterone (PR) and HER2 receptor status and Ki-67 index and fracture occurrence in SM of BC. Exactly 152 samples of SM of BC obtained from individual patients were evaluated. The status of the aforementioned receptors and Ki67 index were determined in SMs samples. Their expression was compared between SM that did and did not develop a fracture. Ninety-one cases sustained a pathological fracture at the SM site, and 61 did not. Patients who sustained a pathological fracture had a higher rate of PR positivity at their SMs as compared to those with no fracture. There was no significant difference between the two groups concerning ER, HER2+ or Ki67 status. SMs secondary to BC with a fracture are more likely to be PR positive than those with no fracture. Determining the receptor status in SMs may identify high-risk groups for fracture occurrence, and determining the PR status may also guide surgical and hormonal therapy.

Expression changes of ER, PR, HER2, and Ki-67 in primary and metastatic breast cancer and its clinical significance

Objective

To explore the altered expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and cell proliferation index (Ki-67) in primary and metastatic breast cancer lesions and the correlation between the primary tumor size, lymph node metastasis, Tumor Node Metastasis (TNM) stage, molecular typing, and disease-free survival (DFS) and their clinical significance.

Methods

A retrospective analysis was conducted on the clinical data of 130 patients with metastatic breast cancer biopsy admitted to the Cancer Center of the Second Affiliated Hospital of Anhui Medical University in Hefei, China, from 2014-2019. The altered expression of ER, PR, HER2, and Ki-67 in primary and metastatic lesions of breast cancer was analyzed with respect to the site of metastasis, size of the primary tumor, lymph node metastasis, disease progression, and prognosis.

Results

The inconsistent expression rates of ER, PR, HER2, and Ki-67 in primary and metastatic lesions were 47.69%, 51.54%, 28.10%, and 29.23%, respectively. The size of the primary lesion was not, but that accompanied by lymph node metastasis was related to the altered receptor expression. Patients with positive ER and PR expression in both primary and metastatic lesions had the longest DFS, while those with negative expression had the shortest DFS. Also, changes in HER2 expression in primary and metastatic lesions were not associated with DFS. Patients with low expression of Ki-67 in both primary and metastatic lesions had the longest DFS, while patients with high expression had the shortest DFS.

Conclusion

Heterogeneity was detected in the expression levels of ER, PR, HER2, and Ki-67 in the primary and metastatic breast cancer lesions, which has a guiding significance for the treatment and prognosis of patients.

Clinical relevance of receptor conversion in metastatic breast cancer: Case report

INTRODUCTION

Breast cancer comprises several different pathological entities defined by the presence or absence of hormonal receptors and human epidermal growth factor receptor 2 (HER2). During the disease course, the increase in tumor heterogeneity contributes to the discordant expression of estrogen/progesterone receptors and HER2 status between primary and metastatic lesions. We describe a case that demonstrates the clinical relevance of molecular reassessment during metastatic breast cancer progression.

PATIENT CONCERNS

A 40-year-old Caucasian woman with germline breast cancer gene mutation was referred to a general surgery appointment after breast ultrasound revealed a suspicious nodular lesion in 2012.

DIAGNOSIS

Ultrasound-guided microbiopsy revealed an invasive ductal carcinoma of no special type, hormone receptor-positive, and HER2-negative.

INTERVENTIONS

The patient underwent modified radical left mastectomy, adjuvant radiotherapy, chemotherapy, and endocrine therapy. Four years after the diagnosis, HER2 positive lung progression was documented, and the patient received anti-HER2 targeted systemic therapy for 15 months. New disease progression with a triple-negative profile was found, and palliative systemic treatment was changed to carboplatin for 3 months until new progression. Based on the results of the OlympiAD trial, monotherapy with Olaparib 300 mg twice daily for 28 days was initiated.

OUTCOMES

After seven cycles of treatment, patient showed progressive improvement in quality of life and maintained stable disease without significant adverse events.

CONCLUSION

The clinical relevance of hormone receptor and HER2 status discordance between primary tumors and metastatic lesions has been studied in recent years. This case report illustrates the clinical impact of molecular changes during disease progression and the adaptation of treatment options. This allows for an increase in both survival and quality of life in patients with metastatic breast cancer.