Genetic Factors in the Locoregional Management of Breast Cancer

circ_0058063 promotes breast cancer progression by upregulating DLGAP5 via sponging miR-557

OBJECTIVE

Accumulating evidence indicates that circular RNAs (circRNAs) contribute to breast cancer (BC) development and progression. However, the role of circ_0058063 in BC and its underlying molecular processes remain unclear.

METHODS

The expression of circ_0058063, miR-557, and DLGAP5 in BC tissues and cells was determined using real time quantitative PCR or western blotting. The functions of circ_0058063 in BC cells were detected using CCK-8, Transwell, caspase-3 activity, and xenograft tumor assays. The specific binding of circ_0058063/miR-557 and DLGAP5/miR-557 was verified using RNA immunoprecipitation (RIP) and dual-luciferase reporter assays.

RESULTS

circ_0058063 expression was upregulated in BC tissues and cells. circ_0058063 knockdown inhibited proliferation and migration but promoted apoptosis in MCF-7 and MDA-MB-231 cells in vitro. In vivo studies further validated that the knockdown of circ_0058063 repressed tumor growth. Mechanistically, circ_0058063 directly sponged miR-557 and negatively regulated its expression. Additionally, miR-557 inhibition reversed the tumor-suppressive effects of the circ_0058063 knockdown on the survival of MDA-MB-231 and MCF-7 cells. Moreover, miR-557 directly targeted DLGAP5. DLGAP5 knockdown suppressed MCF-7 and MDA-MB-231 cell growth, and these effects were reversed by miR-557 downregulation.

CONCLUSION

Our findings verify that circ_0058063 acts as a sponge for miR-557 to upregulate DLGAP5 expression. These findings suggest that the circ_0058063/miR-557/DLGAP5 axis is an important regulator of oncogenic function and may be a promising therapeutic target for BC.

Exome Sequencing Reveals Novel Germline Variants in Breast Cancer Patients in the Southernmost Region of Thailand

Germline carriers of pathogenic variants in cancer susceptibility genes are at an increased risk of breast cancer (BC). We characterized germline variants in a cohort of 151 patients diagnosed with epithelial BC in the southernmost region of Thailand, where the predominant ethnicity differs from that of the rest of the country. Whole exome sequencing was used to identify and subsequently filter variants present in 26 genes known to be associated with cancer predisposition. Of the 151 individuals assessed, 23, corresponding to 15.2% of the sample, exhibited the presence of one or more pathogenic or likely pathogenic variants associated with BC susceptibility. We identified novel germline truncating variants in BRIP1, CHEK2, MSH6, PALB2, and PTEN and annotated variants of uncertain significance (VUSs), both novel and previously documented. Therefore, it is advisable to use genetic testing as an additional risk screening method for BC in this area.

Harnessing Epigenetics for Breast Cancer Therapy: The Role of DNA Methylation, Histone Modifications, and MicroRNA

Breast cancer exhibits various epigenetic abnormalities that regulate gene expression and contribute to tumor characteristics. Epigenetic alterations play a significant role in cancer development and progression, and epigenetic-targeting drugs such as DNA methyltransferase inhibitors, histone-modifying enzymes, and mRNA regulators (such as miRNA mimics and antagomiRs) can reverse these alterations. Therefore, these epigenetic-targeting drugs are promising candidates for cancer treatment. However, there is currently no effective epi-drug monotherapy for breast cancer. Combining epigenetic drugs with conventional therapies has yielded positive outcomes and may be a promising strategy for breast cancer therapy. DNA methyltransferase inhibitors, such as azacitidine, and histone deacetylase inhibitors, such as vorinostat, have been used in combination with chemotherapy to treat breast cancer. miRNA regulators, such as miRNA mimics and antagomiRs, can alter the expression of specific genes involved in cancer development. miRNA mimics, such as miR-34, have been used to inhibit tumor growth, while antagomiRs, such as anti-miR-10b, have been used to inhibit metastasis. The development of epi-drugs that target specific epigenetic changes may lead to more effective monotherapy options in the future.

Harnessing the DNA Repair Pathway in Breast Cancer: Germline Mutations/Polymorphisms in Breast Radiation

Molecular profiling facilitates opportunities for personalization of breast cancer management. Increasing availability of germline and somatic sequencing provides insight into predictors of treatment efficacy and treatment tolerance of patients with breast cancer. The presence of pathologic mutations can guide patient selection for breast conserving surgery vs mastectomy. However, our understanding of the interplay between genetic variants and radiotherapy responses and side effects remains incomplete. Here we review the available data on germline mutations and polymorphisms in breast cancer. We also outline their association with treatment tolerance, locoregional outcomes, and ongoing efforts to transform these insights into more effective treatment strategies in combination with radiotherapy.

Incidence of Occult Breast Cancer in Carriers of BRCA1/2 or Other High-Penetrance Pathogenic Variants Undergoing Prophylactic Mastectomy: When is Sentinel Lymph Node Biopsy Indicated?

BACKGROUND

This study sought to determine the likelihood of occult malignancy during risk-reducing mastectomy in high-penetrance pathogenic variant carriers to help refine axillary staging recommendations.

METHODS

The authors performed a retrospective cohort study analyzing all female carriers of pathogenic variants in BRCA1/2, PALB2 or other genes who underwent prophylactic surgery at their institution between 2006 and 2021. Occult breast cancer was defined as the unanticipated presence of in situ or invasive malignancy on pathologic evaluation of prophylactic mastectomy specimens.

RESULTS

Of 523 women, 243 carriers met the inclusion criteria for the study including 124 BRCA1 (51.0%), 108 BRCA2 (44.4%), and 11 PALB2, TP53, CDH1, or PTEN (4.6%) carriers. The median age was 44 years (interquartile range, 37-52 years). Overall, 128 women (52.7%) underwent bilateral prophylactic mastectomies, and 115 (47.3%) underwent contralateral prophylactic mastectomy. In the 371 mastectomies performed, 16 (4.3%) occult malignancies were diagnosed. Most of the occult malignancies were ductal carcinoma in situ (13 mastectomies, 3.5%), whereas 3 mastectomies (0.8%) contained invasive breast cancer. If Breast Imaging Reporting and Data System (BIRADS) 1-2 or BIRADS 3 findings were reported on preoperative magnetic resonance imaging (MRI), the rate of occult malignancy decreased to 3.0 and 2.8%, respectively, per mastectomy. The patient-level factors associated with a likelihood of occult breast cancer greater than 10% included a history of prior breast cancer, age exceeding 60 years, and BIRADS 4 findings on preoperative imaging.

CONCLUSIONS

Occult invasive malignancy was detected in less than 1% of the risk-reducing mastectomies performed for women with BRCA1/2 or PALB2 pathogenic variants. Sentinel lymph node biopsy can be safely avoided when BIRADS 1-3 findings are reported on preoperative MRI.

CDKN1C as a prognostic biomarker correlated with immune infiltrates and therapeutic responses in breast cancer patients

Breast cancer (BC) prognosis and therapeutic sensitivity could not be predicted efficiently. Previous evidence have shown the vital roles of CDKN1C in BC. Therefore, we aimed to construct a CDKN1C‐based model to accurately predicting overall survival (OS) and treatment responses in BC patients. In this study, 995 BC patients from The Cancer Genome Atlas database were selected. Kaplan‐Meier curve, Gene set enrichment and immune infiltrates analyses were executed. We developed a novel CDKN1C‐based nomogram to predict the OS, verified by the time‐dependent receiver operating characteristic curve, calibration curve and decision curve. Therapeutic response prediction was followed based on the low‐ and high‐nomogram score groups. Our results indicated that low‐CDKN1C expression was associated with shorter OS and lower proportion of naïve B cells, CD8 T cells, activated NK cells. The predictive accuracy of the nomogram for 5‐year OS was superior to the tumour‐node‐metastasis stage (area under the curve: 0.746 vs. 0.634, p < 0.001). The nomogram exhibited excellent predictive performance, calibration ability and clinical utility. Moreover, low‐risk patients were identified with stronger sensitivity to therapeutic agents. This tool can improve BC prognosis and therapeutic responses prediction, thus guiding individualized treatment decisions.

A systematic review of recommendations on screening strategies for breast cancer due to hereditary predisposition: Who, When, and How?

BACKGROUND

Breast cancer is a global health problem that cannot be underestimated. Many studies have shown that breast cancer is related to pathogenic mutations in hereditary predisposition genes. Clinical practice guidelines play a vital role in guiding the selection of breast cancer screening. Little is known about the quality and consistency of guidelines' recommendations and their changes over these years.

METHODS

We reviewed the existing screening guidelines for genetic susceptibility to breast cancer and assessed the methodological quality, and summarized the recommendations to aid clinicians to make decisions. We conducted a systematic search in PubMed, Embase, Web of Science, and guideline-specific databases, aiming to find the guidelines of breast cancer due to hereditary predisposition. The necessary information was exacted by Excel. We also summarized different evidence grading systems. The qualities of the guidelines were assessed by the Appraisal of Guidelines Research and Evaluation II (AGREE II) instrument.

RESULTS

A total of 54 recommendations from 13 guidelines were extracted. Generally speaking, the recommendations were consistent, mainly focusing on mammography and MRI.

CONCLUSIONS

The recommendations differ in details. Moreover, different guidelines are based on different grading systems, and some guidelines are not divided for age limits, which may limit the promotion and implementation of the guidelines. It is suggested that improvement can be made in this regard in the future.