Role of mitochondrial translation in remodeling of energy metabolism in ER/PR(+) breast cancer

Remodeling of mitochondrial energy metabolism is essential for the survival of tumor cells in limited nutrient availability and hypoxic conditions. Defects in oxidative phosphorylation (OXPHOS) and mitochondrial biogenesis also cause a switch in energy metabolism from oxidative to aerobic glycolysis contributing to the tumor heterogeneity in cancer. Specifically, the aberrant expressions of mitochondrial translation components such as ribosomal proteins (MRPs) and translation factors have been increasingly associated with many different cancers including breast cancer. The mitochondrial translation is responsible for the synthesis 13 of mitochondrial-encoded OXPHOS subunits of complexes. In this study, we investigated the contribution of mitochondrial translation in the remodeling of oxidative energy metabolism through altered expression of OXPHOS subunits in 26 ER/PR(+) breast tumors. We observed a significant correlation between the changes in the expression of mitochondrial translation-related proteins and OXPHOS subunits in the majority of the ER/PR(+) breast tumors and breast cancer cell lines. The reduced expression of OXPHOS and mitochondrial translation components also correlated well with the changes in epithelial-mesenchymal transition (EMT) markers, E-cadherin (CHD1), and vimentin (VIM) in the ER/PR(+) tumor biopsies. Data mining analysis of the Clinical Proteomic Tumor Analysis Consortium (CPTAC) breast cancer proteome further supported the correlation between the reduced OXPHOS subunit expression and increased EMT and metastatic marker expression in the majority of the ER/PR(+) tumors. Therefore, understanding the role of MRPs in the remodeling of energy metabolism will be essential in the characterization of heterogeneity at the molecular level and serve as diagnostic and prognostic markers in breast cancer.

Abstract P3-01-15: Significant discordance between clinical and pathological staging in early stage HER2+ and triple negative breast cancers treated with upfront surgery

Introduction: Treatment of early-stage human epidermal receptor -2 (HER2) positive and triple negative breast cancer (TNBC) remains a challenge as disease recurrences and subsequent morbidity and mortality continues to be high for these tumors. Current guidelines suggest a neoadjuvant approach with chemotherapy alone (in TNBC’s), or in combination with single or dual HER2 directed therapy (in HER2 + tumors), for all ≥cT2 disease. Standard diagnostic modalities have oftentimes failed to confirm the correct size of these aggressive tumors. With recent data showing further survival improvement utilizing regimens for residual disease after neoadjuvant therapy, misrepresentation of the true size of these tumors may lead to patients being treated with upfront surgery and potentially missing the added benefits of residual treatment if they were later found to have ≥T2 disease. We aimed to determine whether there is significant discordance between the clinical and pathological staging of these tumors. Methods: We conducted a retrospective analysis via electronic medical record review of a large institutional database from 2008 to 2020. We reviewed all patients with a diagnosis of early-stage breast cancer (Stage I - III) with triple negative or HER2 positive tumors. Patients who received neoadjuvant chemotherapy were excluded. Data on demographics, comorbidities, receptor status, clinical staging, pathological staging, and mortality were collected. Results: Electronic charts from 448 patients were reviewed. 153 patients had ≤cT1 disease. 33 (21.6%) of the 153 patients were upstaged from cT1 to ≥pT2 tumors. Combined imaging modality with mammogram + ultrasound (US) yielded a statistically significant accuracy in clinical staging compared to US alone (82.6 vs. 44.4%; p=0.02). Comparisons between other imaging methods were not statistically significant (mammogram + US vs. mammogram only, 74.1 vs. 82.6%, p=0.41 and mammogram only vs. US only, 74.1 vs. 44.4%, p= 0.13). Conclusion: Significant discordance (>20%) exists between clinical and pathological staging of T1 TNBC and HER2 positive breast cancers. The possibility that these tumors could indeed be ≥T2 lesions is thus a significant concern. This discordance has considerable therapeutic implications. Landmark studies such as the CREATE-X and KATHERINE trials have provided better survival data with the use of drugs such as capecitabine and trastuzumab emtansine (T-DM1), respectively, in patients with residual disease who have undergone neoadjuvant chemotherapy followed by surgery. Combined imaging with mammography and US may yield the most accurate staging. Based on the data from our retrospective study, a strong consideration may be given to offer neoadjuvant therapy to all clinical T1b and T1c TNBC’s and HER2 positive breast cancers. Meaningful survival analysis was not done due to small sample size. Further studies are needed to validate our findings.

Citation Format: Adarsh Sidda, Layana Biglow, Mahmoud Abdallah, Gurusidda Manu, Todd Gress, Maria Tirona. Significant discordance between clinical and pathological staging in early stage HER2+ and triple negative breast cancers treated with upfront surgery [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-01-15.

An updated review of epidemiology, risk factors, and management of male breast cancer

Unlike female breast cancer, male breast cancer (MBC) is rare and not very well understood. Prospective data in the management of MBC are lacking and majority of treatment strategies are adopted from the established guidelines for breast cancer in women. The understanding of biology, clinical presentation, genetics, and management of MBC is evolving but there still remains a large knowledge gap due to the rarity of this disease. Older age, high estradiol levels, klinefelter syndrome, radiation exposure, gynecomastia, family history of breast cancer, BRCA2 and BRCA1 mutation are some of the known risk factors for MBC. Routine screening mammography is not recommended for asymptomatic men. Diagnostic mammogram with or without ultrasound should be considered if there is a suspicion for breast mass. Majority of men with early-stage breast cancer undergo mastectomy whereas breast conserving surgery (BCS) with sentinel lymph node biopsy (SLNB) remains an alternative option in selected cases. Since the majority of MBC are hormone receptor positive (HR+), adjuvant hormonal therapy is required. Tamoxifen for a total of 5 to 10 years is the mainstay adjuvant hormonal therapy. The role of neoadjuvant and adjuvant chemotherapy for early-stage breast cancer is uncertain and not commonly used. The role of gene recurrence scores like oncotype Dx and mammaprint is evolving and can be used as an aid for adjuvant chemotherapy. Majority of metastatic MBC are treated with hormonal therapy with either tamoxifen, gonadotropin-releasing hormone agonist (GnRH) with aromatase inhibitors (AI), or fulvestrant. Chemotherapy is reserved for patients with visceral crisis or rapidly growing tumors.

Breast cancer in a patient with Birt-Hogg-Dubé syndrome (BHDS) with dramatic response to neoadjuvant chemotherapy

This is a case of 49-year-old white woman who presented with a rapidly growing right sided breast mass. A subsequent punch biopsy confirmed grade 3 invasive mammary carcinoma of no special type which was negative for oestrogen receptor, progesterone receptor and Her-2 neu overexpression. She was a carrier of folliculin gene mutation that is characteristic of Birt-Hogg-Dubé syndrome (BHDS), a condition known to cause skin lesions, renal cancers and pneumothoraces. Family history revealed patient's mother, grandmother and maternal aunt developed renal cell carcinomas during their lifetime and were positive for the same germ line mutation. Tumour tissue was positive for TP53 mutation and negative for BRCA1, BRCA2 and other genes commonly associated with breast cancer. We report a patient with BHDS presenting with breast cancer that showed dramatic response to neoadjuvant chemotherapy prior to bilateral mastectomy, local chest wall radiation and 6 months of adjuvant capecitabine.

Bilateral Triple-Negative Invasive Breast Cancer with a BRCA2 Mutation, and Glioblastoma: A Case Report and Literature Review

Breast cancer is the second leading cause of death among women in North America. Glioblastoma is the most common primary malignant central nervous system tumor in adults. The majority of hereditary breast cancers are associated with deleterious mutations in the BRCA1 and BRCA2 genes. Although few case reports have described the incidence of glioblastoma in patients previously diagnosed with breast cancer, any association between BRCA2 mutations and glioblastoma has not been demonstrated to date. Herein, we report a woman who is a carrier of a familial BRCA2 mutation, and was previously diagnosed with triple-negative breast cancer (TNBC) and subsequently with a second primary TNBC and glioblastoma. Further investigation is required to define the possible relationship between these two aggressive malignances and the BRCA2 mutation, which might be critical for the proper management and treatment of this disease.

Creating a Biomarker Panel for Early Detection of Chemotherapy Related Cardiac Dysfunction in Breast Cancer Patients

Cardiotoxicity is an important issue for breast cancer patients receiving anthracycline-trastuzumab therapy in the adjuvant setting. Studies show that 3-36% of patients receiving anthracyclines and/or trastuzumab experience chemotherapy related cardiac dysfunction (CRCD) and approximately 17% of patients must stop chemotherapy due to the consequences of CRCD. There is currently no standardized, clinically verified way to detect CRCD early, but common practices include serial echocardiography and troponin measurements, which can be timely, costly, and not always available in areas where health care resources are scarce. Furthermore, detection of CRCD, before there is any echocardiographic evidence of dysfunction or clinical symptoms present, would allow maximal benefit of chemotherapy and minimize cardiac complications. Creating a panel of serum biomarkers would allow for more specificity and sensitivity in the early detection of CRCD, which would be easy to implement and cost effective in places with limited health care. Based on a review of the literature, we propose creating a biomarker panel consisting of topoisomerase 2β, serum troponin T/I, myeloperoxidase, NT-proBNP, miR-208b, miR-34a, and miR-150 in breast cancer patients receiving anthracyclines and/or trastuzumab to detect CRCD before any signs of overt cardiotoxicity are apparent.