Case Report: Effective Treatment With Pyrotinib and Capecitabine in a Heavily Pretreated Locally Advanced Breast Cancer Harboring Both HER2 Overexpression and Mutant

The prognosis for female patients with locally advanced breast cancer (LABC) has improved with the emergence of novel drugs, especially for those who have HER2 overexpression or ERBB-2 amplification. Trastuzumab-based regimen has been the paradigm in guidelines as first-line therapy, whereas many patients got progressive disease after several cycles of treatment or rapidly progress because of primary resistance. Point mutations of ERBB2 gene occur in both HER2-amplication and non-amplification patients, with a 2% ratio in HER2 non-amplification cohort and 1.48% in HER2 amplication population. The acquired mutation ratio of ERBB2 substantially raised to 16.7%–17.7% in patients prior to trastuzumab treatment. ERBB2 mutation may be a critical reason of resistance and disease progression among the patients treated with anti-HER2 monoclonal trastuzumab or dual anti-HER2 antibodies with trastuzumab and pertuzumab, or tyrosine-kinase inhibitor. ERBB-2 mutation with L755S and V842I indicates resistance to trastuzumab, while that with L755S and K753I indicates resistance to lapatinib; these mutations maybe sensitive to pan-HER tyrosine-kinase inhibitors. A 48-year woman diagnosed with HER2-positive LABC developed trastuzumab resistance after three lines of trastuzumab cross-line treatment with partial response (PR) as the best response. The tissue was performed by next-generation sequencing (NGS), and the results discovered L755S in ERBB2 gene. Then, she received effective treatment with pyrotinib plus capecitabine and underwent mastectomy after six cycles of combined treatment with PR. Subsequently, breast mastectomy was performed, and she took pyrotinib plus capecitabine for 1 year and pyrotinib monotherapy for another 1 year as adjuvant therapy and achieved a long-term clinical benefit. In conclusion, pyrotinib is a potential neoadjuvant agent for patients who are heavily pretreated and harbor both ERBB2 amplification and ERBB2 mutant in locally advanced breast cancer.

Epigenetic Silencing of HER2 Expression during Epithelial-Mesenchymal Transition Leads to Trastuzumab Resistance in Breast Cancer

HER2 receptor tyrosine kinase (encoded by the ERBB2 gene) is overexpressed in approximately 25% of all breast cancer tumors (HER2-positive breast cancers). Resistance to HER2-targeting therapies is partially due to the loss of HER2 expression in tumor cells during treatment. However, little is known about the exact mechanism of HER2 downregulation in HER2-positive tumor cells. Here, by analyzing publicly available genomic data we investigate the hypothesis that epithelial-mesenchymal transition (EMT) abrogates HER2 expression by epigenetic silencing of the ERBB2 gene as a mechanism of acquired resistance to HER2-targeted therapies. As result, HER2 expression was found to be positively and negatively correlated with the expression of epithelial and mesenchymal phenotype marker genes, respectively. The ERBB2 chromatin of HER2-high epithelial-like breast cancer cells and HER2-low mesenchymal-like cells were found to be open/active and closed/inactive, respectively. Decreased HER2 expression was correlated with increased EMT phenotype, inactivated chromatin and lower response to lapatinib. We also found that induction of EMT in the HER2-positive breast cancer cell line BT474 resulted in downregulated HER2 expression and reduced trastuzumab binding. Our results suggest that ERBB2 gene silencing by epigenetic regulation during EMT may be a mechanism of de novo resistance of HER2-positive breast cancer cells to trastuzumab and lapatinib.

Cardiac Melanoma Metastasis with ERBB2 Gene Amplification: A Potential for Future Targeted Therapy

Cardiac tumors are rare, and their treatment differs interindividually regarding the histopathological proprieties and the stage of disease. Authors present a case of symptomatic cardiac melanoma metastasis that expressed an <i>ERBB2</i> (<i>HER2</i>) gene amplification in a course of the disease that has not yet been reported. The frail patient with a history of pulmonary and renal carcinoma, was admitted to the hospital due to a symptomatic left atrial tumor mass. The patient underwent a tumor-resecting cardiac surgery. At first mistaken for myxoma on echocardiography, the histopathological examination of the tumor revealed a melanoma of acral or mucosal origin. The melanoma metastasis was negative for common genetic mutations in <i>BRAF</i>, <i>NRAS</i> or <i>KIT</i> genes, and for the presence of <i>NTRK</i> genes fusions, but carried <i>ERBB2</i> (<i>HER2</i>) gene amplification. The absence of standard gene mutations rendered it unresponsive to treatment with BRAF and MEK inhibitors. This molecular finding is rare in melanomas and represented a therapeutic target for off-label systemic treatment with drugs, primarily aimed at ERBB2 positive breast, gastric, and gastroesophageal junction cancers. A rare finding like this justifies molecular genetic analysis of unusual tumor specimen and guarantees optimal treatment for uncommon types of cardiac metastatic tumors.

A second erb-B receptor tyrosine kinase, ERBB4, is differentially expressed in the tumors of breast cancer patients treated with trastuzumab.

HER2, the human epidermal growth factor receptor 2, is encoded by the ERBB2 gene (1). Trastuzumab, a monoclonal antibody that targets HER2, is utilized for the treatment of breast cancer (2). We recently reported that trastuzumab treatment paradoxically increases HER2 expression in the primary tumors of patients with breast cancer (3). We report here, using analysis of published microarray data (4, 5), that a second erb-B receptor tyrosine kinase, ERRB4, is also differentially expressed in the tumors of patients with breast cancer treated with trastuzumab. Trastuzumab treatment appears to be associated with the up-regulation of two members of the erb-B receptor tyrosine kinase family in human breast cancer.

GENETIC POLYMORPHISM OF RETROPERITONEAL MYXOID LIPOSARCOMA

Objective: to detect new molecular genetic markers and therapeutic targets in retroperitoneal myxoid liposarcoma.Material and Methods. DNA samples isolated from tumor tissue and obtained from formalinfixed paraffin-embedded (FFPE) slides were used. DNA was extracted using the GeneRead DNA FFPE Kit (50) (Qiagen). High-throughput next generation sequencing (NGS) using the GeneReader Actionable Insights Tumor Panel (GRTP – 101X) on the QCI Analyzer version 1.1 platform (Qiagen) was used for molecular genetic analysis of 12 genes involved in carcinogenesis: KRAS, NRAS, KIT, BRAF, PDGFRA, ALK, EGFR, ERBB2, PIK3CA, ERBB3, ESR1, RAF1.Results. Targeted sequencing of retroperitoneal extra-organ myxoid liposarcoma demonstrated genetic heterogeneity. Our study was the first to describe mutations and polymorphic variants in genes, such as EGFR, PIK3CA, ALK, BRAF, ERBB2 / 3, ESR1, KIT, PDGFRA in myxoid liposarcoma.Conclusion. This study demonstrated a wide range of molecular genetic rearrangements in retroperitoneal extra-organ myxoid liposarcoma. Synonymous mutations in the EGFR (Q787Q) and PDGFRA (P567P) genes were detected in all cases (100 %). Missense mutations in the ERBB2 gene (P1170A) and synonymous mutations in the ALK (G845G) and BRAF genes were identified in 75 % of cases. Missense mutation in the PIK3CA gene (I391M) was detected in 25 % of cases. The gene polymorphisms presented in this paper are most likely involved in the carcinogenesis of retroperitoneal myxoid liposarcoma. Further studies with larger patient groups and multivariate analysis of long-term treatment results are required.

The effect of timing of breast cancer surgery during the menstrual cycle phase on the axillary lymph node, estrogen receptor, progesterone receptor and c-erb B2

Background: Estrogen receptor (ER) and progesterone receptor (PR) positivity and c-erbB2 gene expression levels are important in determining breast cancer (BC) development and aggression. Although the importance of hormonal factors in tumor cell proliferation, migration and differentiation is increasing, it needs more evidence. The effect of BC surgery timing during the menstrual cycle on prognosis remains controversial. In order to clarify this hypothesis, we aimed to determine the importance of adjusting the timing of surgery according to the menstrual cycle by examining the relationship between ER, PR, c-erbB2 gene and the menstrual cycle phase in patients with premenopausal BC.Method: Our study was designed retrospectively. 50 patients with premenopausal BC who were operated were included in the study.Results: Our results showed that the patients in the luteal phase had higher ER positivity, PR positivity and c-erbB2 negativity, and the number of metastatic axillary lymph nodes was lower than the patients in follicular phase. Conclusion: BC surgery during the luteal phase in pre-menopausal women is associated with a better clinical outcome. Although larger-scale studies are needed, our results suggest that better results can be achieved by performing surgery in luteal phase in BC patients during premenopausal period.

Biological and clinical features of early triple-negative invasive lobular carcinomas of the breast.

e12570 Background: Hormone receptors and HER2 negative (triple negative, TN) invasive lobular carcinomas (ILCs) are very rare, accounting for 1-2% of all TN breast cancers (BCs). Methods: We extracted data from our prospectively collected institutional database on all consecutive patients (pts) with early stage TN ILC operated at the European Institute of Oncology (IEO) between June 1994 and December 2012. Invasive disease-free survival (iDFS) and cumulative incidence of distant metastases (CI-DM) were calculated. Biological features of these tumors, including molecular intrinsic subtypes based on PAM50 assay, expression of androgen receptor (AR) and mutational status of c-erbB2 gene were also evaluated. Additionally, NGS data of 45 TN ILCs were obtained from 3 large public databases, to confirm mutations in c-erbB2 gene and to identify other recurrently mutated genes. Results: Among 2952 ILCs treated at IEO, 44 (1.5%) were TN and were included in the analysis. All pts received adjuvant chemotherapy. The iDFS rates at 5 and 10 years of follow-up were 47.4% (95% CI, 31.1-62.0) and 29.5% (95% CI, 14.8-45.8), respectively. The corresponding CI-DM percentages were 17.6% (95% CI, 7.6-31.2) and 20.8% (95% CI, 9.5-35.1). The molecular intrinsic subtype was defined through PAM50 for 31 out of 44 TN ILCs: 48% were classified as luminal A, 3% luminal B, 32% HER2-enriched, and only 16% basal-like. The group of pts with luminal A or B tumors had a significantly better CI-DM as compared with pts with non-luminal tumors (i.e. HER2-enriched and basal-like; p=0.003). Luminal tumors expressed AR more frequently than non-luminal tumors (AR≥1% in 96% of luminal tumors versus 53% in non-luminal tumors; p=0.001), and at significantly higher levels (median percentage of AR-positive cells was 80% in luminal tumors versus 15% in non-luminal tumors; p=0.01). Higher AR expression was associated with significantly better iDFS in the whole cohort of TN ILCs (p=0.01), as well as in the group of luminal tumors (p=0.05). 27 TN ILCs of the IEO cohort were analyzed for mutations in c-erbB2 gene, and 9 (33%) harbored mutations. Analysis of the 3 public databases, confirmed c-erbB2 mutations in 9 out of 45 (20%) TN ILCs. All the c-erbB2 mutations found were previously reported to be pathogenetic in BCs and to predict response to neratinib. ErbB signaling and DNA damage response were among the top 10 pathways significantly enriched for mutated genes in TN ILCs. Conclusions: TN ILCs are rare tumors with dire prognosis. Their specific biological features require newly defined targeted therapeutic strategies.